Illuminating: Natural Light in Residential Architecture 9783038216414, 9783764386368

Citation preview

Illuminating

Living Concepts 3 Edited by ETH Wohnforum, Faculty of Architecture Swiss Federal Institute of Technology Zurich (ETH Zurich)

Michelle Corrodi Klaus Spechtenhauser

Illuminating Natural Light in Residential Architecture With an Essay by Gerhard Auer

BIRKHÄUSER Basel · Boston · Berlin

Translation from German into English: Steven Lindberg Design: Michael Klíma This book is also available in a German-language edition: LichtEinfall. Tageslicht im Wohnbau, ISBN 978-3-7643-8634-4 Library of Congress Control Number: 2007943795 Bibliographic information published by the German National Library The German National Library lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.d-nb.de. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, ­ reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data bases. For any kind of use, permission of the copyright owner must be obtained. © 2008 Birkhäuser Verlag AG Basel ∙ Boston ∙ Berlin P.O. Box 133, CH-4010 Basel, Switzerland Part of Springer Science+Business Media Printed on acid-free paper produced from chlorine-free pulp. TCF ∞ Printed in Germany ISBN 978-3-7643-8636-8 987654321 www.birkhauser.ch

Contents

9 13

Introduction Gerhard Auer

Darker Living How Artificial Light Teaches Us to Love Daylight

31

Well Lighted? On the Status Quo of the Hunger for Light

31 31 35 37 38 43 44

Irreplaceable Daylight The Call for Brightness Habits and Positive Attributions Artificial Light The Myth of Light The Myth of Glass Overexposures

49

Modern Living Light-flooded Houses

49 51 53 55 57 60 66 74

Modern = Bright Hygiene through Light and Housing Reform Modern Architecture, Modern Living Equal Heights for Equal People Floor Plan and Typology: Into the Light Increasing Density and Lighting: Rows, Blocks, and Towers In Healthy Light: Balconies, Loggias, Terraces Continuing to Build with Distinction

79

Light, Sight, Space Experiencing Light, Perceiving Space, and Looking Out

79 81 82

Light and Sight Between Inside and Outside Looking Out: Information and Contemplation

84 89 90 92 95 96 99 101 106 108 109 110 112 113 121 124

The Window’s Loss of Importance The Spatial Box: Discretion in Muted Light The Framed View Bursting the Box: New Spaces of Experience Flowing Spaces: Visual Boundlessness and Clarifying Brightness The Form of Windows and the Interior The Mise-en-Scène of Prospects Last Stop: Glass House Rehabilitating Darkness From the Form to the Shell New Pleasure in Transparency: “The Un-Private House” Semitransparent Shells: Veiled Views and the Diffusion of Light Metamorphoses of the Facade Reveiling the Unveiled: Protection from Sun and Prying Eyes Multiple Layers Shown in a Good Light

129

Illuminating: Seeing Well and Seeing ­Comfortably Qualities of Natural Light and Rules of Thumb for Design

129 130

134

158

170 176

Good Light Planning? The Given Situation and Local Conditions: Designing the Exterior The Climate Zone—The Building’s Surroundings—The Sun’s Orientation— The Building Volumes and Facades Quantitative Objectives 134 Interior Design and Functional Lighting The Composition of Natural Light—Terms in Lighting Technology— The Distri­bution of Luminance and Transitions 137 Rules of Thumb for Interior Design The Height and Depth of the Room—The Size and Position of Windows— ­Vertical or Horizontal Openings—Shadows of Other Buildings 144 Increasing and Optimizing Light Light from One Side—Light from More than One Side Qualitative Objectives 158 Interior Design and Seeing Comfortably Light for Information and Wayfinding 159 Directing Light and Shading Modeling Space—Reducing Contrast—Modulating Diffuse Brightness 165 Glare Control Disability Glare from Excessive Luminances—Discomfort Glare from Excessive Luminance Contrast—Silhouette Effect Solar Control and Directing Sunlight Single-Skin Facades—Double-Skin and Multiple-Skin Facades Daylight as Design Medium

181

Lighting Effects: Beyond Seeing Comfortably Well-Being, Mood, Experience

181 182 186 188 191 192 195 196 198 200 206

The Consequences of Flooding with Light A Loss of Homeyness? Physiological and Psychological Comfort One’s Own Four Walls Buffer Zones and Transitional Spaces The Veiled Gaze The Hiding Place The Island of Light The Home as a Place of Memory Lighting and the Experience of Space A Play with Lights and a Theater of Materials

211

Best of: Eleven Masters of Natural Light Landmark Concepts of Light

212 213 214 215 216 217 218 219 220 221 223

Le Corbusier: Purifying Light Richard Neutra: Invigorating Light Frank Lloyd Wright: Vitalizing Light Alvar Aalto: Ephemeral Light Louis I. Kahn: Purist Light Luis Barragán: Meditative Light Tadao Ando: Spiritual Light Jean Nouvel: Illusionistic Light Toyo Ito: Atmospheric Light SANAA, Kazuyo Sejima, Ryue Nishizawa: Suggestive Light Steven Holl: Animating Light

225

Selected Bibliography

228

Illustration Credits

230

On the Authors

230

Acknowledgments

Introduction

MVRDV, Silodam housing complex, ­Amsterdam, 1995–2002. View from an apartment toward the harbor.

During the first third of the twentieth century, residential archi­ tecture began an evolution that even today influences our idea of con­ temporary living far more than we realize. In the meanwhile we know that the ambition and the reality in architectural modernism were further apart than was acknowledged for a long time. If, ­however, we look at current residential architecture and pay atten­ tion to the images disseminated by the media, we are forced to ­acknowledge that many of the demands articulated at the time have lost nothing of their topicality. The idea of bright and open living spaces in particular, more than any other, has taken root in our minds as the epitome of modernity and zeitgeist. “Light-flooded” homes are being built everywhere to satisfy our seemingly insa­ tiable hunger for natural light. The present volume sets out from that trend and its immediately perceptible manifestations—from the fact that for some time now excessive total glazing has been the order of the day even in residen­ tial buildings. Something that until now has been limited to pres­ tigious company headquarters, banks, office buildings, and a few single-family homes is now found in residential buildings construc­ ted with communal or co-operative funding. Tracing this phenomenon, bringing some of its general char­ acteristics and subtle facets to light, and sorting the elements that remain practical for daily use from the surplus of technical ­ know-how are the goals of this book. There are several reasons why the focus is on housing. First and foremost, previous studies on the theme of natural light have always been limited to the worlds of education and work and primarily addressed questions of ergo­ nomics and hygienic conditions at work. But the question of light or rather natural light in the home has never been granted even ­remotely the importance it has in relation to the workplace outside the home. Moreover, the workplace is increasingly being shifted ­into the home—another reason more attention should be paid to na­ tural light in the home. Last but not least, it deserves attention ­be­cause living and working are moving closer and closer together, particularly in terms of lighting, but are subject to different ­demands. It seems obvious that the approach to natural light in architec­ ture cannot be described with absolute quantities and physical con­ cepts. Nor can beautiful pictures hope to present trailblazing 

distributions of light and spectacular lighting situations as a thrill­ ing experience. Rather, natural light—quite apart from its primary definition as electromagnetic radiation—must be understood as a quantity that is rooted in a particular culture and is imple­ mented in building as a productive factor with commensurate com­ petence. Design and planning factors are of equal importance; they are ­mutually dependent and, properly prioritized after careful consideration, are responsible for a convincing design. We are convinced that, precisely with a topic as complex and ambitious as this one, solutions that are focused primarily on ­thorough consideration of the users’ side will lead to not especially satisfying results. Questionnaires may well demonstrate that a “bright apartment” ranks at the top of the list of contemporary desid­ erata for a home. Yet a precise definition of that desire is doomed to fail ­simply because the notion of “bright” is extremely subjective and influenced by the circumstances in question. And considering ­specific standards is not much help either. Furthermore, we think that a work concerned with the theme of natural light in residential buildings has to take into account both contemporary and historical lines of development. Analogous

Patrick Gmür Architekten, in cooperation with GMS Partner, James residential complex, Zurich-Albisrieden, 2003–7. ­Living room and balcony of an apartment in the Langhaus.

10

explanations and expositions are thus an essential component of the present volume, for that is the only way to investigate the complex relationship between living space, human beings, and natural light in a sensible way and to open up our eyes to the connections that exist between the various areas. We are aware that the selection and weighting of individual ­thematic focuses are based on a certain subjective view of things. The selection made ultimately reflects our conviction that natural light in residential buildings is very important primarily where it con­ cerns space and its moods, transformations, and effects. For that is precisely what constitutes the genuine quality of an architecture design: when the sensory, atmospheric, and haptic qualities of natu­ ral light can be experienced in a spatial atmosphere for people. The first three chapters shed light on various essential aspects of the theme of natural light and modern living; the fourth chapter presents the fundamentals of lighting technology and shows how it can influence the planning to achieve good, diverse lighting con­ ditions in living spaces. The fifth chapter treats such categories as ­coziness, comfort, and the experience of space against the back­ drop of the question of lighting. Finally, the sixth chapter presents eleven architects who share a pronounced awareness of lighting in order to give a better sense of different approaches to natural light. We would like to thank here all those who contributed to the ­suc­cess of this project—above all the Velux Stiftung and the 4B Fenster AG, without whose generous financial support the pres­ ent publication would not have been possible. In addition, we are grateful to Gerhard Auer for his stimulating contribution, to the many individuals and institutions who provided illustrations, and to Birkhäuser Publishers whose well-coordinated team has helped to make this third volume in the Living Concepts series a reality.

Michelle Corrodi and Klaus Spechtenhauser June 2008

11

Gerhard Auer

Darker Living How Artificial Light Teaches Us to Love Daylight

Two Prologues You are not likely to find the term “living light” in the dictionary, much less in a textbook, and not even in the title of a seminar on architecture or design. Residential design and lighting design are fields of study, but the lighting designer is just as marginal in the residential world as the question of light is to the home builder. The two of them will meet in the following essay. On the Subject of Light It suffices to take note of the lighting events of an ordinary day to be surprised by their quantity and diversity: On the one hand, there are natural lights—more precisely, the changing natural or cos­ mic variants of light that we encounter in sunshine, under bright or gray clouds, in the twilight of sunrise and sunset, and in exceptio­n­­­­ al cases as lightning or polar lights. On the other hand, we are ­exposed to countless artificial lights, all the interior lighting, street lamps, floodlights, traffic signals, advertisements, and urban ­decorations; last but not least, we have displays and monitors that have spread in our daily lives as light sources happy to conquer, even pressing right up next to our eyes. The light of the worlds we live in is thus more than lamps, more than windows and lightbulbs. It accompanies us inside and out, is a medium of our work and our moods. Artificial lights have only been turning night into day for a hundred and fifty years, and when the day begins, more of them are turned on than turned off. Although until very recently people still spoke of a hunger for light, light pollution is today’s most common light metaphor. Has it already entered our homes? On the Subject of Dwelling The very verb poses difficulties: What exactly constitutes the ­activity of dwelling? Since everyone dwells, it ought to be easy to describe it or at least illustrate it. There is agreement about the ­necessities of bed and table, stove, toilet and faucet. One need only enter a mobile home—the ultimate primitive hut—to have the least common denominator of dwelling before one. That this dwell­ ing demands a protection consisting of roof and wall, door and window, also numbers among its minimum requirements. But opin­ ion is divided on everything beyond that, and the options,

13

f­ unctions, and constructions quickly ramify into the infinite. Every study of dwelling falls apart owing to this chaos of criteria. In the recent past—roughly speaking, the first half of the ­t wentieth century—residential construction was an important topic in Europe for masses of home seekers, and consequently for ­politicians, scholars of the human sciences, and architects. No mat­ ter whether they were discussing the problem of the minimal dwelling, the single-family home, or satellite cities, there was no lack of ideas, and they were realized more quickly than their ­effectiveness was reviewed. Today—after the second, saturated half of the same century—residential construction has declined ­noticeably, and with it the discourses about it. Little wonder, given that the average Central European has more than forty square ­meters of living space. Although new construction is stagnating, moving and renovating are all the more common. Although the debates over styles—villa versus urban apartment block—con­ tinue, the focus in the housing question is no longer primarily 14

­ atterns of developments, forms of stacking units, or typologies for p laying out the given real estate but rather reshaping and updating. Is that still the job of architects, or are we already in the hour of in­ terior design, the furniture industry, and the self-appointed TV ­advisers? Is the maxim “my home is my castle” still valid, or is an obligation that everyone exhibits his or her dwelling simply part of any lifestyle? Housing and Lighting: An Outline of an Evolution The constant switching between sunlight and electric light over the course of the day—which has become a matter of course these days—is a very recent way of experiencing light. The primal hut, no matter whether its origin was a cave or a wooden frame, a tent or an igloo, always had a door but no windows. The archaic shelter needs no daylight. It has to offer security—to bodies, to posses­ sions, to the fire—but not a workplace. The workplace as interior space only became common in urban cultures and the first peep­ holes—still with bars—were only ventured where the palisade or city wall offered cover to the residence. There is no written evidence, but not a little architectural ­evidence, for a history of light in architecture (something that has yet to be written). It would reveal two peculiarities: Until the ­t wentieth century, no residential building would be mentioned in it, and the light source for all the others would be the sun alone. All the early architectural ideas for lighting are in fact found solely in the monumental architecture of church and empire, and most of them reflect cosmic light phenomena: the solar geometry of the Egyptian and Central American pyramids, the transparency to ­color of Gothic cathedrals, shadow-modulated Baroque churches, and the somnambulistic palaces of India and Japan. Perhaps be­ cause it leaves no last remnants, the house—already disparaged with the term “secular building”—has never been a priority for art ­historians. We can learn more about it from paleoanthropologists or ethnologists and perhaps even from myths and legends of our ­origins. According to one Chinese myth, human beings derive from a combination of two races: cave dwellers and tree dwellers, fire worshippers and sun worshippers—and all desires for housing right up to the present have moved between cave and tower, between ­h iding and survey. Sun and fire cults can be traced back well before the beginning of architectural history, and it was the profane hearths and campfires that gave human beings their first experiences with light. If the sun, as creator of the day, was a gift from nature, the hearths and campfires gave off a natural light they could con­ trol—half a million years before the invention of houses and cities. From the very beginning, the city—which was founded on three pillars: the temple, the market, and the wall—has offered a pro­ tective light that can be seen as the first street lighting: the torches of its gatekeepers. When later other “official” illuminations joined it, residential neighborhoods were the last to follow: there it was enough to have a night watchman who loudly reminded people to extinguish the fires they used for lighting until electric light replaced it in the nineteenth century. Just like in the village farmhouse, the fire of the hearth was the primary source of light in urban homes since antiquity, which ensured for a short ­evening and early bedtimes.

15

For all the wealth of variety in housing typologies we can look back on since the invention of the city around five thousand years ago, the constancy of its natural and artificial light is aston­ ishing. Window reveals were reframed according to the style of the epoch, and the lamp wicks given new decorative shades, but the hole in the wall and open flames—ultimately in the form of wax candles and oil lamps—remained the same well into the nine­ teenth century. Adolf von Menzel’s painting The Flute Concert of Frederick the Great in Sanssouci (1852) shows us the maximum lighting of an exclusive night gathering under the supreme luxury of a chandelier. If Shakespeare performed outdoors, then Faust and Mephisto had to declaim from the forward edge of the stage in order to be seen; Goethe commented: “I can think of no greater invention than candles that would burn without being trimmed.” Until the middle of the nineteenth century, the evolution of nat­ ural and artificial light in secular buildings saw no highlights ­ or innovations, and for that reason were not mentioned in any archi­ tectural treatises. Everything would change for both forms of ­lighting in the second half of the century: the engineers of steel-and­glass halls with no walls and the technicians of incandescent ­lighting joined to invent new miracles of lighting. Like the transpar­ ency of London’s Crystal Palace (1851) by day, the unsuspected brightness of artificial white heat excited not only the public but also architects, though they treated both with skepticism. The steeland-glass skeleton was at first refused entry into the art of architec­ ture, and initially a practical significance but no aesthetic importance was attributed to electric light. Glazing and lighting revolutionized urban transportation and department stores, factories, and nightlife. In homes, by contrast, at first all that happened was the candles were replaced by gas flames or lightbulbs, but the cande­ labras and chandeliers in the middle of the room remained what they were: decorative spotlights. The situation was no different with daylight. Whereas train stations, markets, and photographers’ ­studios put up glass facades and roofs to welcome it in, home deco­ rators still draped the heavy curtains around the slit windows. Even the boulevards of Paris owe their balconies not to a desire to look out but to the fire-prevention authorities. The turbulent innovations of the first era of artificial light were never stimulated by housing construction but rather by the motors of the industrial revolution, none of which wanted ­n ighttime to pass unexploited: the military, the factories, the public space, and the variety theater. Their spotlights, floodlights, and garlands of lights were of little use, of course, in the home, and so only one light source had a career there: the lightbulb. It was not in­ vented by Edison, but he adapted it to mass production—in order to utilize his power plants to the full. Sewers and gas and water pipes had already put into practice the network principle that would make it possible to pack homes even more closely together and make their residents dependent on others—as they remain ­today. Electricity, initially a luxury product for which customers had to be courted, only became successful with the housing and ­hygiene crises of the turn of the century. Die Wohnungsfrage (The Housing Question), Friedrich Engels’s political polemic of 1872 (rev. 1887), made it the leitmotif of a humanitarian construction 16

­­ effort. Bourgeois reformers saw urban rear buildings—in compar­ ison with the large rooms in their own front buildings—as sources of illness owing to the cramped spaces and physical proximity. As it seemed impossible to change that, the promise of good health took the form of opening them to light, air, and sun (all inexpensive gifts from nature). The opening of apartments to light became popular in bourgeois apartments at the same time, from whose ­salons people had never before looked through the curtained win­ dows. A new “back to nature”—which gave wing first to the youth movement and then to Jugendstil—brought the lesson of the Crystal Palace, fifty years later, to housing construction: windows, balconies, roof and winter gardens soon formed part of the lifestyle of a higher-income elite. In model housing developments, such as the Mathildenhöhe in Darmstadt, the Art nouveau of housing was presenting the first aesthetic wedding of window decoration and lighting design, a short-lived marriage of natural and artificial lighting design that would only find parallels in recent times. For ornamental lighting design was soon confronted with a func­ tional design that brought a lighting rationale that had been tested in factories into the rooms and kitchens of ordinary people. The discovery of the socially motivated avant-garde that trans­ parency and electricity could compensate for a shortage of space provided inspiration and set standards for the housing modernism that followed. And the spring cleaning of styles did its part: smoothed and skeletonized furniture took up less space; prefabri­ cated, standardized, and unornamented windows were cheaper than craft products. 17

By the end of the 1920s, the defining experiences of housing and lighting had already been made that would continue, in more or less varied form, into the postwar period. The visions of the re­ formers had been fulfilled without question. When the issue of hous­ ing dominated the discourse on architecture for the first time, residential construction became a model collection of the best de­ signs of the most talented architects: Antoni Gaudí and Charles Rennie Mackintosh designed total works of art as translucent spatial sculptures; Frank Lloyd Wright exploded the walled-in box, ­designing houses as enormous hearths surrounded by light wall and ceiling screens. The European master schools exported the flowing daylight of their white cube model homes as far as the ultimate all-glass transparency of Californian villas. While at home in ­Europe, the utopia of a housing provided by the welfare state that was suited to families and could be mass produced multiplied to the point of monotony. The brilliance of individual masterpieces, the seductive construction boom of the postwar economic miracle, and a faith in the science of functionality worked together to blind people to a fundamental principle of housing: it escapes any attempt to idealize it and hence any standardization, every mass production, every social optimization. That is even more true of in­ terior than exterior design. A panorama of the highlights of late-modern housing reveals the metamorphoses of the window from hole to transparent ­skeleton; the metamorphoses of electric light from the lightbulb to the elimination of every trace of shadow. Yet its light hygiene was even less a success with the public than its weight-loss programs for form. The self-critical finale in the 1980s was not a sobering up but an intoxication: in a brief span, not only were the historical pleasures of architectural decoration rediscovered, but a utopia was buried: the possibility that the planning of life and the planning of architecture could be united. Postmodern and posthistorical, pluralistic and individualistic—not only were architectural styles ubiquitous, so was a lifestyle that pretended to reject every dictate of style. Never before was there so much simultaneity and indif­ ference in tastes and fashions, and residential lighting today shows, with the porthole next to the all-glass display case, with the fireplace next to the wall-length plasma screen, new ­ecstasies rather than anything that could still the appetite for light, but we are also discovering new spaces of refuge from light. Close and Open, Hide and Display Höhlenausgänge (Exits from the cave) was Hans Blumenberg’s title for a study of the cultural history of the modern age, which can be described as a continued striving for knowledge and enlighten­ ment. Designers of space should recognize philosophers as their most inventive source of keywords. For it is not just Plato’s parable of the cave that deals with light and space: from Empedocles to ­Plotinus, from Lao-tzu to Alhazen, from Grosseteste to Descartes, from Newton to Hegel, from Heidegger to Wittgenstein, from Bachelard to Baudrillard, from Lyotard to Deleuze, we are at least enlightened about the error that spaces are stable or that the truth is manifested in brightness and transparency. By contrast, in the work of E.T. A. Hoffmann we encounter a cave opener of ­practical intelligence: Councilor Krespel, who has a house built for

18

himself. Rather than engaging a planner, he thoroughly paces off his property, walking around the property line and back to the cen­ ter, where he finally marks out the position of his four walls in situ. Then he hires workers and has them build walls, without any openings, to a height that pleases him. Only at the end does he ­order his masons to punch out the holes for the windows, large and small, high and low, however the sunshine and prospect inspire him. What an architect! At a time when architects were concerned with symmetries and historical styles, he not only practiced a func­­­­ tionalism avant la lettre but also gave a new direction to the ex­pert’s gaze: outward. If architecture since antiquity had given ­priority to the view from outside, so that designing a space consisted in the composition of Euclidean solids and planes, then our diplomat (!) Krespel anticipated the lived, tempered, physically experienced space of phenomenology. Around the middle of the twentieth century, the first media theorist, Marshall McLuhan, will suggest grasping visual space as auditory space: as unlimited directionlessness; ­Gaston Bachelard had earlier called it an experience and all new de­f­ initions of it ever since agree that light and space are dynamic ­phenomena that require synesthetic perception and a performative approach. Panes of glass alone, which joined the window hole in the form of the bourgeois winter gardens of the turn to the twen­ tieth century, do not alter the perception of space; initially, they were just sun catchers for bay windows and winter gardens that oc­ cupied an entire floor. Not until the panorama window of early modernism—after ferroconcrete had made the horizontal slit win­ dow possible—would the pleasure of seeing step in and frame ­prospects. Japanese gardeners call the panorama beyond the garden wall a “borrowed landscape” and build it into their designs for the foreground. Krespel’s unconventional annexation of the outdoors extends the feeling of the dwelling—once synonymous with ex­ periences nearby and introspection—to the borrowed horizon. Even the full transparency of the glass living boxes can no longer open space wider. On the contrary, the completely transparent villa is either compelled to veil itself or damned to isolation behind its own park walls or hedges to prevent unwanted gazes—but also prospects. The protective function of housing fulfills a need for security, not only of body and soul but also of goods and assets. In uncertain times, the home has to be a bunker and a hiding place: then its open­ ings are closed and traitorous lights are extinguished. Only in the secured city and at times of peace can people live in illuminated skeletons. Philosophy’s liberation of the awareness of the self stirred up in everyone the same desires for the status symbols that had first been available only to kings and priests and later to the rich bour­ geoisie but that today any participant in a talk show can have. Andy Warhol predicted that in the future everyone would be famous for fifteen minutes. As courtly and bourgeois lifestyles had done earlier, democratized housing became an opportunity to gain pres­ tige or even celebrated as what Thorstein Veblen called “con­ spicuous consumption.” The Biedermeier salon may have ended up as a caricature of philistinism, but the catch phrase “Show me how you live, and I’ll tell you who you are” was an advertising slo­ 19

gan in a furniture industry that wanted to equal the turnover rate in clothing fashions. With similar ideas in the back of their minds— “Are you still just dwelling or are you already living?”—some are slander­ing the wall-to-wall shelving of yesterday in favor of a ­lifestyle of rapid exchange. Supposedly those TV shows are popular in which a new home decor is imposed on clueless bunglers that in the end ­always looks as refreshing as the salesrooms at IKEA. But all the ex­hibitionism of the have-nots is futile: where there is ­nothing de­sirable to conceal, there is nothing worth seeing to display. Jacques Tati’s films—from Mon Oncle to Traffic—describe more ­accurately than any sociological critique could the tragicomedy of demon­strative living. Showy ambience is ultimately only an obliga­ tion for celebrities, who are, of course, not to be seen, admired, or robbed in reality and in situ. Protected at home by bodyguards, they ­present their lifestyles in glossy magazines or on talk shows. The ­at­titudes of hiding and exhibiting that now in­fluence the media no longer establish the style or act as a role model for a sustained ­archi­tectural culture that today only reaches a large audience when it ­offers sensations to curious viewers. All in all, these findings

are not worth complaining about, as they merely locate the theme of­ hous­ing in a less public niche, where it can be reflected on ­without the frenzy. With television, the limits to visibility fall away: the final, most space-consuming opening brings a new source of light into the home, the televisions and computer screens and their anticipated suc­ cessors, which are turning into a new genre of lighting, with a sur­ prising consequence: whereas the first artificial light made night day, the final one compels darkening, making day, if not night, then at least perpetual twilight. The facade has already reacted. It veils its transparency in various ways: the familiar curtains for ­privacy or venetian blinds against the sun have been followed by slat blinds, perforated sheet metal, glass bricks, frosted glass, and printed panes. They recall the grilles for Arab harems or Japanese paper ­sliding doors, rehabilitated decorative glass and muntins. For all their aes­ thet­­icizing, however, they have the same prosaic goal: dimming the day to a background for virtual reality that is easy on the eyes. Reception and Manipulation: The Four Lights of Living Space Light, whether from natural or artificial sources, seems to reach people only via one entrance: the eye. But our brain immediately dis­ tributes it to several sectors: these are the levels on which designers of space should work, and they need to distinguish between a functional, an aesthetic, an emotional, and a somatic level. If the present book is to be dedicated to manipulations of daylight—that is, to an architecture of windows—the following four sketches should include the manipulations of artificial light.

First and foremost, we owe our vision to brightness, to a useful light that makes our perceptions and activities possible and is there­ fore vital. In its natural form (or force), we can only encounter it receptively (or defensively): architects turn their floor plans toward the proper light: wall openings and windows have to respond to the whims of the sun. Lighting with artificial light, by contrast, can be more aggres­ sively controlled and precisely planned. The open fire was its first in­ strument: the oil flame, lightbulb, and all the other hot lighting technologies are derived from it. Artificial lighting, because it can be measured and tested, is treated more extensively in textbooks and standards than natural light is, which has to manipulate a dynamic and unreliable supply of brightness. Nevertheless, windows and daylight should also be designed with utility in mind. For the reliable paths of the sun make it possible to plan shade precisely and result in an arithmetic based on experiences of the direction of the sky, the dimensions and position of a window, and the depth of the space. Orientation and information signals with no lighting function should also be counted as useful light: signs, pictograms, last but not least the screen as the new star of light sources. An instruction manual for the useful lights in a home can be simply formulated and easily satisfied: Give each activity its own light and only the necessary amount! Do not light rooms but rather workplaces! Avoid flooding with uniform brightness: do not drown every pleasure of living! The nocturnal ambience should be like a landscape of scattered campfires, not an open-plan office. 21

The fact that functional use of light is inevitably perceived as aesthetic or emotional as well, lies in the ambiguity of our connota­ tion of light and in the ambiguity of all light’s manifestations. In its second role, light appears as an agent of an aesthetics of light, which also emerges from conscious design but transcends the pure visual aid: shadow sculptures emerge beneath spotlights or highlights; figure and ground can be separated by contrasts in luminance; the decoration of a facade is improved by means of ornamental, colored, or moving illuminations in artificial light. Aesthetic light design can make use of qualities of daylight, choreo­ graph the course of shadows and variations in brightness, vitalize a static space, combine with water, materials, and colors to form a synesthetic poetry like that of a rainbow over a fountain or in Gothic church windows. The aesthetic of artificial light has a tradi­ tion in nighttime rituals and fireworks; its most beautiful tasks are those on the stage in a theater; and since electrification its diver­ sity in facade decorations, entertainment, and housing is all but ­unbeatable. 22

In residential spaces, where an aesthetic use of daylight demands special refinement of architects, interior designers step in; they ­prefer to work with lamps and hence with artificial light, which is, without question, a decorative medium par excellence. Ev­ ery lamp that wants to be more than an aid to seeing belongs in this second genre, for religion or display of status, as symbolic or ­narrative, as decoration or advertising sign in light, and the less it has to illuminate, the more it can retreat into semidarkness, where magic has its place. As a rule of thumb for aesthetic, decorative lights in the home, there is only the warning against excess, which, if consumed daily, quickly leads to surfeit. As a precise counterpart to the aes­thet­ ic refinement of the twilight boundary, wasteful festive lighting ­belongs to the same family. There is no need to fear exaggeration, to shy from any kitsch. For sumptuousness cannot ruin anything here, since the spice is the brevity of the performance. The third power of light, this time a suggestive one, works on the edge of consciousness: there where our emotions are stimulated by phenomena of light such as sunsets, cities on fire, or disco lights.

There is a lot of talk about atmospheric or mood lighting these days—particularly effusively in advertising brochures from the lighting industry, which now promises to enrich our emotional lives—but there is virtually no scientific information about ­atmospherically tempered space. Ever since “atmosphere” (global breathing space), a technical term borrowed from meteorology, be­ came a metaphor—first in poetry from around the turn to the twentieth century, then in Heideggerian philosophy of “tempered space”—it has been haunting, not without reason, the jargon of ­designers of space: who would not like to acquire a hold on the un­ predictable phenomena of light in nature and art that trigger our moods? In a sense, any layperson can do that: a candle on the dining table is the tiniest example of a lighting mood that always succeeds. But what are its ingredients? First, there is often a real fire in play, and the domestic hearth also proves itself as an atmosphereinducing medium par excellence. Often what we describe as atmo­ spheric are natural experiences (a lightning storm or sheet of rain, a volcano eruption or moonlight, marine phosphorescence or the polar lights), and the idea suggests itself that all artificial mood lighting should be interpreted as attempts to imitate natural events. According to another interpretation, however, the multi­ purpose metaphor should not be attributed solely to large-scale natu­ ral phenomena, but rather emanates from every event, every space, and even every object as a kind of suggestion of an aura. Then every situation and every moment would be characterized by a ­specific atmosphere, including the mood of the recipient—which would ultimately make it impossible to reconstruct. The most ­­ far-reaching analysis of the atmospheric is that of Gernot Böhme, who has equated it with the “character” of a space that we are in the habit of describing with attributes such as narrow or wide, burdening or uplifting, serious or festive, sublime or petty, ­stimulating or boring, cozy or elegant, masterful or petit bourgeois, and so on. He notes—and this seems to me useful as advice to ­designers of space—that these moods cannot be objectified architec­ turally and can only be experienced in physical presences, because they “communicate between the objective qualities of an en­ vironment and our sense of being.” In his view, light, color, and sound, but also materials, geometries, and proportions, can be em­ ployed in a conscious production of atmospheres, which would bring the designer close to the stage designer or interior designer. It is understandable that, because they want to stimulate their ­atmosphere, the theater, a party, or large circus events strive for imi­ tation atmospheres. That can indeed be achieved by employing fire, smoke, lighting, veils of water, and Wagnerian sound can cer­ 24

tainly be successful, but surely not in a home. The more discretely the artificial lights in the latter relate to the first and second categories, the more inventively the windows respond to daylight, the more certainly will moods be evoked on their own—as gifts from nature or chance. Finally, a fourth, somatic light reaches only our body. Only ­recently did dermatologists learn that our skin is a light-processing organ and neurologists discovered that there is an appreciable quantity of information that our eye takes in that does not simply serve vision but rather regulates our hormone balance as well as our vegetative and chronobiological circulation. Achieving its ­effect on us outside of conscious sensory perception, somatic light would seem to be a fact that escapes design interventions. Light designers should, however, be concerned that we know too little about the potential harmful effects of radiation from artificial light: 25

a few positive results—for example, success with showers of light against depression in Scandinavia—are opposed by catastrophe warnings of psychological and physical damage from constant ­artificial light. Although the expectations of health that housing re­ formers around 1900 had from “light, air, sun” were not based on medical science, their hunch appears not to have deceived them: a century later, studies of the brain have discovered how their ­imitations and surrogates take it out of the human body. These days the sun, having outlived its usefulness as a hygienic message, may have become the new hope of the energy sector, and enormous pieces of evidence of solar autarky decorate the roof of every ­progressive house. But solar scientists would be putting on blinders if they were only interested in it as a source of electricity and not as a source of healing. The designers of future light spaces—now still helpless in the face of the physiotherapeutic challenge—will have to turn to ­natural light (or natural darkness) with new motivation: as health care that works subcutaneously. And what laboratory will be better suit­ ed for that than the home? Progressive Twilights Not a few Europeans were surprised when UNESCO declared the night sky to be a precious treasure that is the most endangered and most worthy of preservation of all: endangered because only three percent of the stars were visible above conurbations, with a downward trend. The Milky Way has become invisible for two-thirds of all Americans. And that is not just an aesthetic problem for ­amateur astronomers: the domes of artificial light above all densely

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populated regions are a long-term threat to populations of insects, birds, and mammals in entire regions. The German word for the light pollution that has been documented worldwide makes it seem harmless: Lichtverschmutzung (literally, “dirtying with light”). The Victory over the Sun—the title of a Russian opera that in­ spired Malevich to create his black square in 1913—that is, the tech­ nical brightness that has been available in excess for 150 years, has without question, like all technologies before it, made life more comfortable and the world more controllable. The genetic im­ printing of Homo sapiens by light, however, during the half million years at least that the species has known fire (but also respected darkness), was not essentially changed by a century of colonization of night: our body needs sleep and even without advances in chro­ nobiological research senses its dependence on the sun. With regard to innovations, artificial light can point to rapid progress in the technologies for its use, which today concentrate mainly on energy savings but nonetheless continue to be used pri­ marily in advertising, decoration, and entertainment in public space. Recently there have also been forward-looking tasks for light emerging from ecology, medicine, digital visual communication, and last but not least from the correspondence with the exploitation of solar energy. Not coincidentally, they all call rather for dimming and more subtle shading: new areas of research into twilight are being announced. The euphoria of imitating the sun and the prescientific myths of light’s healing powers have in the meanwhile proven to be dan­ gerous errors: in particular because the eye was known only as an instrument of vision. That not all lighting promotes human welfare was already clear from torture by sleep deprivation or by over­ powering spotlights. Nevertheless, doubts about the blessings of civilian illumination did not arise until late-shift workers and de­ partment store personnel began to complain about insomnia and nervous disorders. Even more alarming, but still inexplicable, were the long-term effects of a windowless model school in New York in the 1970s, where the students were found to suffer above-average numbers of psychological, physical, and intellectual deficiencies. In 1987 the so-called melatonin hypothesis was proposed to explain this; since 2001, however, with the discovery of new processes ­between the eye and brain, we have the proof: human beings can be the victims of light poisoning. A brief digression on that subject is unavoidable here. Two facts and one consequence: In addition to the receptors (rods for brightness and cones for color) known previously, a third, cryptochrome detector of light was discovered in 2001; it passes its information only to the pineal gland and the suprachiasmatic nucleus (SCN), a multi­ functional hormone regulator and moderator of the body’s daily and annual rhythms. It reacts only to the shorter wavelengths in the sun’s spectrum (crudely: to blue light). Short wavelengths of artifi­ cial light can, however, deceive the SCN—and hence misdirect our bodily functions. A number of hormonal and vegetative—meaning unconscious— controls of mammals follow circadian rhythms, that is to say, they are synchronized with the phases of light and dark of the course of the sun. The active phase corresponds to the brightness of day and the sleep phase to the darkness of night. Following this genetic 27

program will ensure our well-being. Problems and health risks ­ egin for the disobedient: shorter wavelengths of artificial light dur­ b ing the night phases activate stress hormones at the biologically ­incorrect time. The effects have been underestimated until now: it has been proven that not only “nervous disorders” result but also physical damage, depression, and cancer. The consequences would be simple: move work back into the daylight, emit less artificial light—and then only longer wavelengths. But the photonic catastrophe will be treated like every other catas­ trophe of which a majority of people become aware only through massive advertising. Who wants to hear that tomorrow it will be necessary to make radical corrections to the light in cities and streets, in offices, in department stores and factories?

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Before the global totalitarianism of artificial light can be recog­ nized as a crisis, however, the home should be defended privately as a lighting biotope deserving protection. Not only against the threat of interior designers but even more so against the residents’ own forgetfulness concerning light. Where, if not in our own homes, can we determine ourselves the dose of radiation and reject damaging artificial light? Where else can we ask ourselves when we reach for the light switch whether we really need it now? Our homes benefit once again from their technological back­ wardness: we still allow ourselves warm incandescent light, there are still windows that give residents the freedom to give in to their own circadian feeling for daylight. The less we trust ersatz light, the more sparingly we will use it, the more carefully we will approach wall openings, perhaps even install a hearth and under­ stand our balconies as a place from which we can maintain no-­ cost contact with natural light and the cosmos of light. The common description of human beings as visual animals, be­ cause we supposedly take in eighty percent of our information through vision, causes misunderstandings: not only because infor­ mation is not precisely defined here but also because the need for space and the representation of our senses in our brains vary widely. There the information obtained by hand and skin are in the first position, followed by hearing and taste, and only then vision, which requires far less brain activity. Why do we close our eyes on so many occasions in order to maximize concentration and sensitivity—or to prepare the ultimate pleasures? The home will—if its function as representation and status, its communitarian and familial functions turn out to be more interchangeable—be able to fulfill another promise: being a niche to withdraw to enjoy undisturbed, which requires the conspiratorially restrained light of which we can remind ourselves from all situations and ex­ periences of deriving pleasure.

Well Lighted? On the Status Quo of the Hunger for Light

Irreplaceable Daylight Hardly anyone today would deny the significance of daylight or of its beneficial effect on the human psyche and organism. Especially recently, visual sensitivity seems to have moved even further in the direction of natural light, even though there is considerable uncertainty about how lighting effects are achieved. In addition to the many half-truths in circulation, the following things are known for certain: Daylight, with its regular fluctuations, determines how human beings perceive time (seasons and day-night or circadian rhythm) and is a crucial influence on hormone balance. Similarly, daylight has influenced the history of the evolution of the visual organ: the eye is most effective in daylight, and the assessment of a specific lighting situation is always based, consciously or unconsciously, on a comparison with experiences in daylight. It is, moreover, known that the vividness and variability of natural light, its constantly changing intensity as the direction of radiation shifts, and its broad spectral composition are qualities that cru­ cially determine our sense of well-being and have been proven to lead to improved mental productivity while reducing symptoms of tiredness. Constantly changing illumination is not just stim­ ulating but also contributes to the visual assessment of one’s ­surroundings. Consequently, the appearance of the objective environment changes from morning to evening, from a cheerful sunny day to the colorless gray of a murky November fog. Last but not least, the natural light that enters a room establishes a rela­ tionship to the outside world, a significant psychological factor that is of tremendous consequence when assessing a spatial situation.

Gigon / Guyer Architekten, Residential building, Diggelmann­strasse, Zurich­Albisrieden, 2005–7. Living area and ­balcony.

The Call for Brightness If you look at the want ads for apartments in central European newspapers, one thing stands out above all: most of the buildings extolled there are described as bright or even light-flooded. ­Something similar is found in the studies on so-called housing requirements that sociologists conduct with a certain regularity, which are then supposed to be used as clues for building housing. The criterion “bright” or “sunny” always occupies one of the first places on the list of the most important qualities for housing. Although it may no longer seem that way, this desire for rooms as bright as day is relatively new. Roused in us just a few

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Daylight conveys fundamental information about weather, season, and time of day; its vividness determines the life rhythm and well-being of humans.

­ ecades ago, it subsequently became a seemingly essential demand, d whose rigorous fulfillment continues to represent one of the most superficial goals of contemporary residential architecture. Yet it is by no means a so-called basic need, as anthropologists, for ­example, have attested by reference to the need for protection and security. Whereas a feeling of security is essential to human ­­ self-identification, light-flooded rooms are not the must they are generally claimed to be. After all, we lived for centuries in relatively dark homes and evidently suffered no substantial damage, neither physically nor psychologically. Although varied and ­sufficiently bright lighting can stimulate the human organism, the same effect is achieved by even a brief period outdoors. Medical opinions still differ regarding how much natural light an organism requires daily to avoid biophysical disorders. The needs for and demands placed on living situations turn out, in fact, to be much more a product of society and the experiences individuals have in it. On closer inspection, the call for more light turns out to be an unconsciously internalized pattern of ­perception and action that cannot be fully understood independently of the economic and social circumstances from which it emerged. The call for brightness is closely connected with a change in percep­ tion and a new understanding of space. It is the cultural product of a society in the early twentieth century that had broken with the past and originated in the preformulation of a supposed social need that had to be satisfied. The triumph of modern living and its influence on lifestyles today cannot be adequately explained ­without reference to the pedagogical efforts of the protagonists of the Modern Movement. The call for “light, air, sun,” which became a slogan in the 1920s, employs terms that were borrowed from hygienics. Whereas modernist architects focused their efforts on light and sun, in the nineteenth century the emphasis had been much more on air. The scourge of that era was bad air, to which pathological effects were attributed. The individual terms were weighted differently in the propaganda for a modern aesthetic—a circumstance that has been totally forgotten today. The flinging open of the facade—the most important feature of modern living—should also be understood in no small measure as an act of compensation to achieve sufficient lighting despite the massive shrinking of space in the wake of the minimal standard advocated. The switch from vertical to horizontal windows during the 1920s should also be seen in this context: when the height of ceilings, which at the time was commonly over three meters, was reduced in order to save money, vertical-format windows had to be reconsidered. Although it was more a problem of proportions and hence an aesthetic issue, considerable effort was made to argue solely scientifically and objectively: with the argument that horizontal windows supposedly offered better—because more uniform—distribution of light was used to make the horizontal ­format more palatable to clients. At the same time, the window increasingly evolved from ­something that provided light to something that offered a prospect: as standards of living rose, increasing the view from the ribbon or panorama windows became very important, which also contributed to the continual increase in window formats.

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But why has the proportion of glass in facades grown so con­ siderably right up to the present day? In the meanwhile, we not only tolerate the sometimes undifferentiated frenzy for windows without any great resistance but also encourage it with our desire for rooms that are as bright as possible. And the architectural main­ stream does its best to serve us with ever new appeals. In fact, the need for brightness in rooms by increasing the available natural light seems only to increase. Why?

Contemporary living in bright and open spaces: in the 1930s and at the beginning of the twenty-first century: Max Ernst Haefeli, Koellreuter House, ­Küsnacht, Canton of Zurich, 1931–32. ­Living room. Kuhn Fischer Partner Architekten, Limmatwest housing complex with commercial spaces, Zurich West, 1997–2002. Living room.

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Georges-Henri Pingusson, Latitude 43, Saint-Tropez, 1930–32. View from an apartment over the Bay of Saint-Tropez.

Habits and Positive Attributions In physics, there is the so-called law of constancy, which can be ­interpreted to provide one possible answer to this question. Awareness of brightness is relative: “Memory is not in a position to store absolute values of brightness, contrast, color, dimensions, and time. For that reason, there is no absolute scale for space and time.”1 Perception is a continuous and usually unconscious process, although in assessing space it is essential to realize that the im­ pression of brightness can only be judged in comparison to a familiar situation: “The laws of constancy have been known for some time; all that is new is the knowledge that they have to be learned and that the learned state has to be constantly renewed and re­ inforced by additional sensory experience. The standards can only be preserved if they are constantly experienced anew.”2 One explanation for the still undiminished consensus that a ­residence should be as bright as possible is thus the fact that our perception of light has changed. Apparently, we demand light-flooded rooms because we do not know things any other way, because we grew up that way, because we are subjected to it everyday by the media, and finally because the equation bright = better that has been drummed into us by numerous parties for decades has finally become effective with the appropriate reaction time—housing is by nature conservative—and fallen on fertile ground. Other factors have an influence as well: for example, the view that daylight is “healthy.” In a society in which the theme of health will soon supersede the age of information and knowledge, natural light—to say nothing of the potential energy savings—is considered increasingly important because of its positive attributes. Finally, more and more people spend a large portion of their lives in buildings, cars, trains, and airplanes, and hence in an artificial climate, which may increase the desire for nature, weather, sun, and daylight. At the same time, we attribute to certain sources of artificial light ­negative effects on our health: there is, for example, a consensus that fluorescent lamps give off an unnatural and hence “unhealthy” light. Such connections of mental concepts do not necessarily correspond to scientifically proven facts. Faith or subjective experiences alone can determine our assessment of what we perceive.

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Final inspection of fluorescent lamps in the Philips factory in Roosendaal, The Netherlands, 1950s. Arkadij Šajchet, Lenin’s Lightbulb, 1925.— Peasants in the Soviet provinces delighted in electrical technology. Electric light as standard for all. The ­extension of the day into the night calls for ­socializing and family cohesion.

A.H. Steiner, Heiligfeld III housing development and residential high-rises at the ­Letzigraben, Zurich, 1950–56. Living room of a four-room apartment with sample ­furniture in a residential high-rise.— ­Modern, light-flooded living in the 1950s.

Artificial Light One of the most important factors that massively influences our perception of light is artificial light, whose permanent availability has accustomed us to a high level of brightness. Since 1900 sources of artificial light have grown more and more efficient and electricity cheaper. Very soon it was not just luxurious villas or public buildings but also a majority of all residences that had them. The ­ new possibilities for artificial light extended the day into the night, transformed the centers of cities into illuminated backdrops, and improved the function of living rooms as centers of familial domesticity. Metropolises such as Berlin, Paris, and New York ­acquired an entirely new look with illuminated advertisements and neon signs. It was the birth of a process that declared the effects of artificial lighting to be an essential factor in modern architecture and hence not only assumed the power of light to create space but also profited from the new possibilities of lighting technology to put architecture in the proper light.

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Technological progress and economic prosperity helped arti­ ficial light become even more important during the second half of the twentieth century. Buildings were erected everywhere that ­ignored natural light entirely and illuminated every corner of every room with artificial light. Dark rooms and areas began to seem rather antiquated. The consequence of this thirst for light is obvious: namely, that the almost unlimited possibilities of artificial light were bartered for a bit of dreary shadelessness. The mystic, mysterious atmosphere of darkness or semidarkness was at most still ­acceptable in sacred buildings as a counterpoint to bright, “divine” light. The Myth of Light Since time immemorial, light has had universal significance for all religions of all eras and nations. Light is equated with birth, ­creation, and salvation. Although paradise—be it heaven, Olympus, or Valhalla—always resisted precise localization, one thing was clear: it is defined by infinite, eternal brightness; its radiance reveals itself anew every day, and even when the sky is overcast it can ­penetrate the cloud cover all the more dramatically and grant new life energy “as an emissary of the divine light-ether that is not ­directly accessible to human kind,” as Wolfgang Schivelbusch has described it. We need only recall numerous depictions of the ­A nnunciation or, somewhat more profanely, Siegfried transfigured by the mythical light in Fritz Lang’s eponymous film of 1924, ­pausing in the forest and awaiting a new surge of divine power.

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Ladislav Žák, Villa Hain, Prague-Vysocˇ any, 1932–33.—The fascination of day/night ­effects.

The extreme religious and symbolic significance of beams of light changed little even after light was studied scientifically by Sir Isaac Newton in the early eighteenth century. As Werner Oechslin emphasizes, artists who glorified Newton’s discovery made use of traditional pictorial means to “surround the profane with the aura of the divine.”3 The science of light just added a new level of meaning to the religious, mystical symbolism of the light ray: it became the emblem of the Enlightenment. More than two hundred years later, finally, advances in artificial lighting opened up a new, entirely profane field of operation for the light beam, which ranged from the flashlight to headlights and the advertising slogan projected onto the sky. Soon exhibitions, sporting events, jubilees, theater performances, and last but not least the propaganda and self-promotion of totalitarian regimes made use of the enormous effect of spotlights, and not without playing with the light’s historical levels of meaning. For example, ­the ­“cathedrals of light” and light beams staged by Albert Speer, the chief architect of the Third Reich, were a fixed feature of the National Socialist monumental aesthetic that was supposed to transport the all-powerful Führer into a transfigured, divine light. Also Stalin seemed to take on godlike features when, as part of the electrification campaign in the Soviet Union during the 1930s, he was depicted as a colossal ruler over light and dark. 39

Divine ray of light: Siegfried pauses to ­renew his strength before he is murdered from ­behind by Hagen at a spring. Film still Sieg­frieds Tod from Fritz Lang’s Die Nibelungen, part 1: Siegfried, 1924.

And architecture? At least since the Modern Movement adopted a deliberate, objective approach to design, it may seem obvious that the repertoire of light’s symbolic meanings should be jettisoned, and light instead treated rationally and functionally. That is not what happened, however: even the modernists did not shy away from equating lots of light—whether natural or artificial—with an enlightened, progressive stance. To the extent that light served to illuminate totally, it was supposed to be effective in a metaphorical sense against mental impurity. In addition to these fantasies of salvation through enlightenment, several proponents of modernism were certainly interested in cultivating light as a fascinating and diverse medium. In the midst of the cult of brightness there was a handful of architects who investigated the counteracting forces of darkness and sought to play with the various levels of meaning, symbolic values, and manifestations of light. Le Corbusier’s descrip­ tion of architecture as “the masterful, correct, and magnificent play of volumes brought together in light”4 has become famous. Com­ petence and regularity alone, however, do not make for architecture; it needs the poetic power of natural light to enliven the building volumes and show them off plastically to best effect. Le Corbusier did not really make good on this maxim until his late work, “in which light plays a decreasingly ‘objective,’ and increasingly ­symbolic, mysterious, poetic role, delineating and intensifying volume, space and architectural meaning.”5 Natural light can still be fascinating today, even in a society that is largely secularized and digitalized. It has preserved its ­historical connotations and lost nothing of its auratic power, even though it can be explained by physics and reproduced artificially. Never­ theless, most architectural designs still foreground the intensification of light, and in view of our limited resources, ­daylight is sup40

posed to serve primarily to flood and illuminate space. Against the backdrop of forced scenarios of artificial light or uniform illumi­ nations, it is above all architects such as Alvar Aalto, Louis I. Kahn, and Luis Barragán who remind us to incorporate into the archi­­tec­ tural project the value of light for design and experience. In the wake of an excessive focus on the spectacle, there is also a risk of oversaturation: where once postmodernism, with the best of intentions, advocated ennobling and overdoing surfaces to combat horror vacui, today it is postrational constructors who sometimes employ an excess of messages in light. Only a few have been able to develop an original style with light in which nat­ ural light functions as the true building material.

Light and electricity under the sign of ­totalitarian power: Tok vkljucˇ en [The current is switched on]. Stalin on a double-page spread in the journal SSSR na strojke [USSR in construction]. Benno von Arent and Arthur Reiche, Lighting of the columns on Unter den ­Linden in Berlin for Mussolini’s visit in September 1937.

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Gigon / Guyer Architekten, Residential building, Diggelmann­strasse, Zurich­Albisrieden, 2005–7.—Glass is increasingly more appre­ciated thanks to its qualities of visibility.

The Myth of Glass As with light, the success of glass—as the epitome of a modern ­architectural mentality—should not be attributed solely to its functional purpose as a provider of natural light. Its attractiveness points rather to “inner connections, to the radiant and yet icy dimen­ sions of the material, and to its myth.”6 Glass seems to have a ­greater potential than any other building material to harbor phil­ osophical and ideological meanings. With its specific qualities of transparency and hardness, lucidity and impenetrability, it has always been surrounded by the aura of the fascinating, the ­wonderful, even the sublime. It is revealing in this context that the word for glass in Romance languages resembles veritas (truth): “the crystal ball of the fortune teller and the transparency of the En­ lightenment, providence and resistance, free view and obstacle, a metaphor for melancholy and for purity.”7 It is thus not surprising that, over the course of its history, architecture made use of this spectrum of references and meanings and employed glass apart from its function as a simple light source. This was probably formulated most powerfully in the early twentieth century by Paul Scheerbart in his visions of architecture, in which he called for a comprehensive design of the surroundings using colored glass: “We hope that glass architecture will improve people ethically as well. That seems to me one of the major advantages of gleaming, colorful, mystical, great glass walls.”8 With its symptomatic use of glass, modernist architecture appealed to much more than just its physical properties. Its proponents’ demand for “naked” and “honest” architecture transferred the dictate of candor to the material as well. Transparency became the symbol for a new architectural conviction that typified the new ­virtues of openness, freedom, and equality and hence a decidedly democratic stance. We need only recall in this context Hannes Meyer’s explanations of his competition entry for the Palace for the League of Nations in Geneva (1927), in which glass played a crucial role: “no crooked corridors for diplomats’ crooked moves but rather open glass rooms for the public negotiation of public people.”9 The pedagogical components of modernism in the first third of the twentieth century, which are reflected in the conception of architecture as a socially relevant act that creates community, found its adequate means of expression in the glass, with its quality of ­laying things open and exposing them. In new, well-lit architectural spaces, everyone should feel like he or she is participating in the common project of modernism. From today’s perspective, such statements may seem excessively emotional and outdated, but they were characteristic of the optimism and sense of a new era at the beginning of last century. The con­ gruence of theory and practice was, however, already marked by contradictions. For what could the generous windows of the ­Tugendhat House in Brno have to do with a specifically democratic architectural conviction? And that transparency—which implies seeing into and seeing through—could certainly become a signifier of visual control is also demonstrated by designs for prisons ­en­tirely of glass that were already being produced in the nineteenth century.

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If, after many years, crystal palaces are enjoying a revival, and the glass facades of countless banks and company headquarters influence the image of today’s city centers, it has nothing to do with democracy either, of course. Nor does it when Sir Norman Foster places a glass dome on the Reichstag in Berlin. Rather, it is about buildings in which the use of glass has long since become solely an aesthetic concern. The transparency of our day is no ­longer that of our ancestors who believed in reality. Glass, freed of its didactic obligation, is now being used visually again—that is to say, as an experiential value or as a means of suggestion. Overexposures Architecture made of glass is not yet architecture made of light, even if it sometimes seems as if the lighting issue could be resolved by designing with sufficient window area. If in what follows we talk about deficiencies, it is not about deficiencies of lighting but rather about a general ignorance about the possibilities for designing with light. While there are protagonists of a richly nuanced architecture, their play with light and shadows has little influence on the mainstream, which still prefers to follow the famous equation from the industrial age more light = better light. On the one hand, the demand for living space should be understood as the concretization of a complex profile of demands, and the form it takes is dependent on society’s values and norms. On the other hand, the supply of living space is the result of an in­ vestment decision whose realization as architecture usually occurs within a restrictive financial framework. As a rule, the power to decide lies with the clients or investors. In general, they decide about the look, quality, and substance of housing and in the process are usually guided by, in addition to economic aspects, their own notions of housing: building is very closely tied to con­ ventions. People do not like to lean out the window, since trying out new things is associated with uncertainty and represents—as long as demand dictates supply—an unnecessary risk. The market tries to respond to so-called trends, which is why today’s approach to natural light often reflects an undifferentiated acceptance of conformist ideas. The presentation of certain images of archi­ tecture in the media plays a crucial role in this, affecting residents and developers in equal measure. In an age dominated by images, it is only logical that the original dialectic of the window as a light source, on the one hand, and as a prospect, on the other, would be eliminated in favor of the latter. Inadequate plasticity and spatial tension are often the negative results of such design maxims. The architect and architectural theorist Juhani Pallasmaa has addressed where such reduction to the two-dimensional can lead:

44

Claudia König and Werner Larch, D House, Vienna-Hietzing, 2003–4. Living room.— Diverse and variously employed design means lead to subtle handling of light.

“Most of the buildings praised in the international press in recent years are characterized by narcissism and nihilism. It is about time that the primacy of the visual finally be overturned in favor of a ­resensualization, reeroticization, and reenchantment of the world.” Consequently: “Architecture has the task of bringing back the inner world. For rather than experiencing our being here in the world through our architectural space, architecture has descended to ­becoming the art of the printed image, having lost its plasticity and materiality.”10 For Pallasmaa, the neglect of plasticity goes hand in hand with a disenchantment of the world. This criticism can be ex­ panded and continued to include a call for a kind of architectural design that once again focuses on space and hence on the effects of depth, whose importance for life experience in times of illumination without shade has to be made clear again. Moreover, that which seems to any lighting consultant to be a ne plus ultra for visual and ergonomic reasons does not necessarily coincide with the ideas of a human being seeking calm and a home. Dwelling implies a close interaction between human beings and their environment, for, on the one hand, the living environ­ment shapes the individual and, on the other, the resident designs the environment as well. Hence latitude for action—opportunities to design and personalize the space oneself—are of central importance. Often, however, they are limited by restrictive ­solutions for the floor plan. It is not sufficient to consider the planning of natural light from just one perspective if one wants to do even approximate justice to the complexity of this set of themes: building is the result of the interaction of various factors and should not be measured by ­statistics on lighting technology or energy. Rather, design should be an open process in which answers from all relevant fields are sought to the question of how human beings feel in the space provi­d­ ed to them. An undogmatic synthesis of various approaches makes sense, since the human being needs more than reason and 45

Richard Neutra, Nesbitt House, Los Angeles, CA, 1942. Living room.

logic to feel alive and well. The poetry of space does not just mean the presence of four walls; it includes a desire for a harmonious, ­diverse ambiance that makes it pleasant to stay there. A dwelling is above all a living space, one that permits great variation in terms of the use of daylight or the quantities of natural light. Hence there need to be a call for more willingness to experiment and more ­boldness in planning residences—a field that, as Richard Neutra once put it, demands more sensitivity than others and precisely for that reason deserves our full attention: Architecture for habitation, perhaps more than any other, is a highly realistic, immense, and inexhaustible art. But—the thought recurs—it is not an abstract art far from life, which idolizes mate­ rial, “interesting constructions,” or “pure forms,” glass cubes and other geometricities, or again manipulates with shadows, light, and color and assembles these into an external, anorganically conceived production per se. Here it is evident that our art has to deal most responsibly with the humanly “sensible,” the sensorial as well as the mental, a fabric into which these manifold yarns are ­woven—in short, with the happenings of our inner life or, what one used to call simply, the soul. Looking for a home remains basically searching for lasting happiness.11

1 Heinrich Kramer, “Die menschliche Wahrnehmung,” in Ingeborg Flagge, ed., Jahrbuch Licht und Architektur 1998 (Darmstadt: Das Beispiel, 1998), 8–11, here 9. 2 Ibid. 3 Werner Oechslin, “Light: A Means of Creation between Reason and Emotion,” Daidalos 27 (1988): 22–31, 34–38, here 26. 4 Le Corbusier, Toward an Architecture, ed. Jean-Louis Cohen, trans. John Goodman (Los Angeles: Getty Research Institute, 2007), 102; Le Corbusier-Saugnier, Vers une architecture (Paris: Crès, 1923), 16: “L’architecture est le jeu savant, correct et magnifique des volumes assemblés sous la lumière.” 5 Harris Sobin, “Masters of Light: Le Corbusier,” AIA Journal 68, no. 11 (1979): 56–59, here 58. 6 Michael Erlhoff, “Bauen mit Glas: Bloss Glas—der klärende Widerspruch,” ­Baumeister 89, no. 1 (1992): 11. 7 Ibid. 8 Paul Scheerbart, Glasarchitektur (Berlin: Gebrüder Mann, 2000; originally, Berlin: Der Sturm, 1914), 88. 9 Hannes Meyer and Hans Wittwer, “Ein Völkerbundgebäude für Genf, 1927,” Bauhaus 1, no. 4 (1927): 6. 10 Juhani Pallasmaa, architect and architecture critic, at the symposium Archi­tektur und Wahrnehmung (Architecture and perception) in Frankfurt, Novem­ ber 2002, quoted in Werk, Bauen + Wohnen 90/57, no. 3 (2003): 69. 11 Richard Neutra, Mensch und Wohnen / Life and Human Habitat (Stuttgart: ­A lexander Koch, 1956), 314.

47

Modern Living Light-flooded Houses

Sigfried Giedion’s programmatic publication Befreites Wohnen, 1929. Original photograph and cover (terrace of Rotach Houses by Max Ernst Haefeli, Zurich).

Modern = Bright The writing of cultural and architectural history has, together with its visual strategies, contributed fundamentally to generating a very specific idea of modern design. For example, the equation modern = bright originated in the perception, acceptance, and appre­ ciation of the products of High Modernism and the era of the 1920s and 1930s, which was marked by a sense of a new awakening and of a lust for life, by a will for social reform, and by cultural ­experiments. As a result, even today products are labeled “modern” if they win us over with their constructional clarity and formal ­reduction and are full of functionality and graceful legerity. They always seem to be surrounded by an aura of the bright, the ­illuminated, the transparent. That is true even of, or especially of, residential buildings: Le Corbusier’s villas, Mies van der Rohe’s ­Tugendhat House, and the elegant West Coast villas in the famous photographs of Julius Shulman. They are all marked by generous use of glass as a material, which helps show off the open, bright, light-filled interiors. These icons of housing—note that they are all villa buildings for the upper class and not the often praised large developments in Frankfurt am Main, Vienna, or Amsterdam, which employed far more traditional approaches to design—have shaped our image of cosmopolitan, urban, contemporary living for decades. That is all the more astonishing given that modern buildings ­accounted for only five to ten percent of the total volume of new construction in the 1920s and 1930s. By contrast, the dark sides of modernism have always received far less attention, even though the return to a complex play of light and shadow was an essential characteristic of the architecture of the second half of the twentieth century. Thus attention is paid to the mystic, idealized effect of light at most in sacred build­ ings such as Le Corbusier’s Notre-Dame-du-Haut chapel in ­Ronchamp (1950–55) or his Dominican monastery Sainte-Mariede-la-Tourette in Eveux-sur-l’Arbresle (1953–60). By contrast, his Villa Shodhan in Ahmedabad, India (1955–57)—a masterpiece of the expressively formed, sculptural buildings of his late work, which synthesizes light and color, the bright and dark areas into a magnificent spatial experience—is not nearly as deeply im­ printed on the collective memory of architecture.

49

Light-flooded icons of modern residential architecture: Ludwig Mies van der Rohe, Tugendhat House, Brno, 1928–30. View from garden. Pierre Koenig, Case Study House No. 22 (Stahl House), Los Angeles, CA, 1959–60.

Le Corbusier, Villa Shodhan, Ahmedabad, India, 1951–56. Living room.

It is not just a selective writing of architectural history that has fundamentally influenced our present image of modern housing. The idea of a light-flooded home was indeed an essential item on the program of the proponents of the Modern Movement on their path to a comprehensive reform of housing. After the First World War, contemporary housing defined by the slogan “light, air, sun” was supposed to pertain to buildings not just for the social elite but for the broad masses. In particular, the significance attributed to natural light as healthy became a progressive factor in designing floor plans, building volumes, and layouts of developments. Natural light became a crucial factor in choosing the correct orientation of rooms and buildings, in developing adequate patterns for building and typologies for developments, and in designing the peripheral exterior living spaces of houses and apartments. Hygiene through Light and Housing Reform When social reform groups began efforts to improve living condi­ tions for the working classes in the middle of the nineteenth ­century, it was above all the deplorable hygienic conditions of hous­ ing they denounced. The many texts by doctors, social critics, ­politicians, and later architects were largely similar in content. There was a broad consensus that poor, stuffy, and dark housing led to illness, aversion to work, or depression. Because of this perspective, their efforts focused on avoiding bad air. It was considered the main evil as a pathogenic risk. Air—and not, as we might initially assume, light—was also what played a role in determining the adequate size of apartments for the working class. Today we are astonished that relatively stately ceiling heights of three meters or more were retained even in ­tenement housing for the working class, the vast majority of which was built by speculators. Unlike the bourgeois apartments that filled an entire floor, where ceiling height was a measure of social distinction and evidence of the economic status of the residents, in the case of working-class apartments this was also due to a per­ ceived need to provide sufficient oxygen levels. Remember that at the time sometimes six or more people where crowded together in one room and had to live together with limited living space. With a population density that can scarcely be imagined today, get­ ting sufficient air to breathe was ultimately a question of econom­ ics, since, after all, labor power had to be preserved. In the middle of the nineteenth century, the German doctor Max von Pettenkofer calculated a rule of thumb for air exchange in rooms: 10 m 3 of air per adult and 5 m 3 per child. These requirements for suitable ­working-class apartments, which were later made law, were, as a rule, implemented under strict cost controls. Because surface area was restricted by the perimeter block development dictated by urban planning measures, it was sometimes cheaper to obtain the required air space with higher ceilings.

51

Arthur Wragg, Schau—die Sonne! (Look— the sun!).—Direct sunlight was rare in the densely built-up perimeter block con­ structions in the working-class neigh­ borhoods of large cities.

As is evident from contemporary descriptions, dampness in apartments was considered the main problem, and so ventilation was also associated with inadequate air supply. Not infrequently, greed for profits led to apartments being rented before they had dried out adequately, and sometimes the location and size of the apart­ ments made sufficient ventilation nearly impossible. If, especially in the last third of the nineteenth century, the calls for adequate light grew increasingly loud, this was, despite its later interpretation, primarily associated with the hope that the dampness thought to promote disease could be avoided. The light coming in was sup­ posed to prevent musty rooms by providing radiation to dry them out. This connection was made, for example, by an 1891 publi­ cation from Basel’s association for apartment owners, which ­urgently called for “the driest (sunniest), airiest (largest), and ­quietest room” being used as the children’s room, since dangerous childhood diseases bred “in cramped, stuffy, poorly ventilated, and overfilled living rooms and bedrooms.” At the same time, sunlight was credited with being able to kill germs owing to the ozone that supposedly formed from oxygen and sunlight. Apart from overcrowded housing, which was consid­ ered the main cause of contagion, poor lighting seemed to con­ tribute to the deadly circulation of disease and the rapid spread of germs. Consequently, numerous texts asserted that light had an ­a ntibacterial effect—an argument that would stick in the collective consciousness for generations. The insistence of housing reformers on favorable spatial condi­ tions that were supposed to have the positive effect of counteracting the needy lapsing into immoral behavior, underwent another change of emphasis at the end of the nineteenth century. In addition to combating the sources of harmful illness, the goal was increas­ ingly social prophylaxis. Cleanliness and purity in the home—always in association with the bourgeois principle of morality—became an important concern of the reformers. Natural light thus became a conditio sine qua non; after all, the filth first had to be made visible, as is clear, for example, from this passage in a medical hand­ book from the 1890s on healthy living: “Wherever dust, dirt, fluff, and spiderwebs are found on tables, the floor, walls, windows, or furniture, the industrious and prudent housewife immediately reaches for her cleaning implements, her brooms, mops, and damp rags to remove these enemies of clean air and decency.” From that time onward, the chain of associations of dirt with bad, immor­ al, sick, and asocial and of cleanliness as virtuous, innocent, and healthy were deeply etched in people’s minds. Around 1900 the science of hygienics, which united the fields of bacteriology and social medicine, was established as a recognized aspect of the medicine of health. In the years that followed, there was, on the one hand, a popularization in broad sections of the pub­ lic of knowledge about how diseases occur and can be avoided. On the other hand, concern with health—along with the postulate of housing suitable for families—underwent a boom in reformers’ ­circles, and discussions of it and laws drafted to address it were fed by the latest knowledge from the physiological science of ­ hygiene. Light and air soon became their most important demand, although this did not have much effect on the building codes prior to the First World War. 52

If the motivating forces and main initiators of the hygiene movement and the associated pedagogical efforts among the people had primarily been committed social hygienists, politicians, and civil servants until this time, modernist architects from the 1920s on­ ward also increasingly exploited their era’s faith in science for their own purposes. The scientifically defended claim for “light, air, sun” was perfectly suited as propaganda for the programmatic ideas and aesthetic principles of the Modern Movement.

Hugo Höppener, Bade in Licht, Luft & ­Sonne (Bath in light, air, and sun), 1901.

Modern Architecture, Modern Living By the end of the 1920s, modern architecture had established itself as a force to be taken seriously. Exhibitions throughout Europe presented modern architecture and contemporary living with great success; large cities were being filled with dynamic commercial and office buildings in the new style; the educated middle class paid attention to the zeitgeist and had modern domiciles built; the first fortunate people moved into new housing developments with stan­ dardized and rationalized floor plans. There was even room made for the Modern Movement in survey works. Moreover, the founding of the Congrès internationaux d’architecture moderne (CIAM) 1928 in La Sarraz in western Switzerland created a new, international podium for the discussion of current themes and future solutions in architecture. One of the central concerns of the Modern Movement was a comprehensive reform of modern housing. The latter was supposed to be a symbol of a new lifestyle, for the social and political trans­ formation that occurred after the First World War had also changed society’s expectations of architecture. The majority of architects, planners, and theorists of modernist inclination associated new paths for architecture with a socially and politically progressive stance and had ambitions to provide corresponding architectural answers to current demands and problems. It is not surprising that the ­emphasis for many was on socially oriented residential building, since many European countries suffered acute housing shortages after the First World War. Moreover, weak economic circumstances called for rational, cost-efficient construction. Standardization, normalization, and unification of form thus became the guidelines that pointed the way to the future. The new design maxims of ­simplicity, functionality, and plainness were also linked to ethical and moral ideas for a more human and democratic society in the ­future, which would prevent catastrophes such as the First World War. Modern living in new buildings was intended as a crucial ­contribution to developing a new, enlightened, socially competent, and even “spiritual” human being. For example, a contemporary publication on the new architectural attitude read: “These homes, which are designed so lightly and unpretentiously, do indeed seem to be educators for a new spirituality. While they are designed, on the one hand, to provide their inhabitants with the purest and healthiest sources of live, they demand, on the other hand, a cer­ tain asceticism, forgoing some non-spiritual comfort and inte­ gration ­into society.”1 Yet the protagonists of the Modern Movement were certainly aware that such a program could not be implemented from one day to the next—certainly not with the masses. Con­ sequently, they showed an élan not seen since for imposing a kind of education on the culture of living and through numerous

53

A Mercedes-Benz model (Type 8/38 hp, Stuttgart 200, Roadster) in front of ­ Le Corbusier and Pierre Jeanneret’s duplex in the Weissenhof housing development in Stuttgart. Advertising photo, 1928.—­ At the very latest when contemporary archi­ tecture is used as a backdrop for auto­ mobile advertising, its protagonists should have achieved their objective.

publications, events, and exhibitions presented the new architecture and its concepts for living. The model housing developments produced by various sections of the Werkbund between 1927 and 1933, the film Die neue Wohnung (Modern living) by Hans Richter (1930), and publications such as Die neue Wohnung: Die Frau als Schöpferin (Modern living: Woman as creator) by Bruno Taut (1926) and Befreites Wohnen (Liberated living) by Sigfried Giedion (1929) are among the most notable of these efforts. 54

Redesign of the apartment in accordance with the ideas of the Modern Movement: Simplicity and formal clarity instead of ­floridity and decorative ornament. Liberated living in the Neubühl Werkbund housing development, Zurich, 1928–32. Advertising photograph for Wohnbedarf aluminum furniture by Marcel Breuer. The photograph’s wife, Lita Finsler, is stand­ ing in the doorway.

Equal Heights for Equal People As a path to a better future, the plain, functional aesthetic of the new residential buildings was also intended to express social equal­ ity. For all this ideological background, however, people were faced with a very real problem: how to finance all of this. As part of the publicly supported housing construction that became dominant in the 1920s in the form of communal and nonprofit cooperative housing associations, the focus had to be on lowering construction costs. Leaving aside for the moment the possibility of increasing productivity through standardization and rationalization of the con­ struction process, which could only be achieved by reducing the costs of materials and the furnishing of the apartments. The logical consequence of such restrictions was inevitably a minimizing of living space and ultimately a reducing of the ceiling heights that had been common until that time. Correspondingly, in response to the acute housing shortage there were urgent discussions of the prob­ lem of the minimal dwelling, with a shift from the earlier concern for the height of rooms to an interest in floor area. After all, faced with tiny living spaces, who would even want to discuss ques­ tions of appropriate proportions of the space? On top of all that, and this was probably essential, in the meanwhile hygienics had dis­ covered that it was air circulation and not, as previously assumed, the quantity of air that was the crucial factor in a healthy

55

living ­environment, so that ceiling height was definitively consid­ ered a quantity that could be ignored. Walter Gropius defined the “question of the minimal dwelling” as matter of determining “the elemental minimum of space, air, light, and warmth human beings need to develop fully their life functions and not to experience restrictions as a result of housing” and pronounced, evoking ­hygienics, “that, provided that ventilation and the provision of sun­ light are ideal, human beings need, from a biological standpoint, only a very small amount of living space, especially if it is properly organized in terms of the technology for using it.”2 The command addressed to architects was clear: Enlarge the windows, reduce living space! With that, the continual opening up of the facade, which had only been made technically possible by modern skeleton-frame construction, took its course. Thereafter re­ duced ceiling heights of 2.4 meters, such as those in the Werkbund housing development Neubühl in Zurich-Wollishofen, were no ­longer the exception. In fact, the ceilings in Neubühl were original­ ly planned to be only 2.3 meters high. That contrast with the amount of total window area, which at an average of 38% of the floor area far exceeded the current legally defined guideline of 10%. ­Accordingly, when the development was finished, it was emphasized that “all the windows extend up to the ceiling, resulting in favor­ able lighting of the depth of the rooms, despite a reduction of clear ceiling height to 2.40 m.”3 As early as 1919, in four experimental buildings in Basel, “the minimal dimension of the new building code was hesitantly employed for the first time: 2.30 m c[lear] height!”4 The author’s exclamation point suggests the reduced ceiling height was still a small sensation at the time. As the living space was ­reduced, its connection to the exterior space increased: when there was no direct access to the garden, it was compensated for with large windows. Just as architects claimed to solve the housing problem scientifi­ cally, so the hygiene of light became the binding norm of the ­Modern Movement. The position of wall openings was now decided more from functional perspectives for the inhabitants, to achieve a supposedly optimal brightness. In reality, however, the lighting ideal of modernism led to the maxim the brighter, the better.

Transformation of the proportions of the room and the window surfaces, 1800 ­versus 1933: Ceiling heights lower, new window forms, increased percentage of window surfaces.

56

N Heating

Laundry

Front yard

Housek.

Entrance (Circulation Zone) Garage

Closet, WC

Entrance

Kitchen

Garden tools

W

Pantry

Working

Kitchen garden

Maid’s r.

Child

Living room

Dressing room

Free space

E Child

Child

Bathroom

Guest

Eating

Living

Housekeeping

Storer.

SleEping

Bathroom Parents Yard

S Orientation of the living areas according to compass points.

Floor Plan and Typology: Into the Light Although over time the residential floor plan has repeatedly been the point of departure for both major and minor reforms, the basic principles of its layout have changed comparatively little from the 1920s to the present. Many of the residential floor plans pro­ duced by the free market are still based on traditional patterns and arguments, even though they have lost much of their original ­significance in the meanwhile. While the majority of today’s success­ ful players demonstrate little willingness to leave the beaten track and take a path that deviates from the norm. Now as ever, the spatial subdivisions of the Modern Movement are adhered to, in which sleeping, living, cooking, and eating were broken down into separate activities and assigned a special room or oriented toward a par­ ticular point of the compass. Thus sleeping must at all costs be done facing east, while living and eating faced south or west. More ­flexibility was shown with regard to the entrance and access areas, and even a northern prospect was tolerated for the location of the housekeeping area, that is, the kitchen. This maxim for designing the floor plan, which is still considered valid today, was the result of a fierce critique of existing workingclass apartments. Whereas the layout of floors in the late nineteenth century had been based on rows of individual rooms of the same size, gradually a functional arrangement of the floor plan, as part of an optimization of the course of living from a Taylorist perspective, gained acceptance. This was based on the insight that such a lay­ out would be beneficial to the physical well-being of the working housewife and minimize any signs of fatigue. At the same time, the housing reformers turned their attention to providing the rooms with sufficient natural light. Already up to this point there had been an increasing sensitivity to the theme of light, but between 1920 and 1930 the accent shifted from one of providing light to one of pro­ viding sunlight. Daylight, specifically the direct insolation, ­became

57

the guiding measure of residential building. Correspondingly, the floor plan, orientation, ceiling heights, and distance from neigh­ boring buildings were supposed to ensure that every apartment ­received a minimum amount of direct sunlight even in winter. Whereas in a free-standing single-family home the individual design of the building volumes and floor plan could adequately meet the specific demands of orientation, this became considerably more difficult when several units were combined. The challenge for the architect was to choose a system of access that was appropriate in terms not only of ensuring sunlight in the apartment but also in terms of cost-effectiveness. In the context of the question of the overarching subject of the form of the housing development, people gradually realized that it was necessary to transform radi­ cally the existing urban planning guideline in favor of open ­developments. The initial impulse for new layouts for developments and ­general improvement of living conditions came from the English garden-city movement, which had been gaining foothold on the Continent as well since the turn of the century. The garden city idea was based on small-town and rural models and aimed, in the spirit of cooperative organization, to form socially and econom­ ically autonomous communities. Its model of zoned separation of various functional areas and roomy construction based on row houses or single- or multifamily homes was not without influence on later housing developments and the possibilities of opening up inner-city space. As part of the extensive publicly funded programs for res­ idential buildings in the early 1920s, a number of modernist archi­ tects considered open, uniform development to be the salvation from the block perimeter development of the late nineteenth century and its health and social shortcomings. Building in rows—the Zeilenbau—was considered, but that would have necessitated aban­ doning the existing street grid. Instead, the layout and access of residential buildings was increasingly considered from the perspec­ tive of optimizing sunlight. Building in rows was intended to create not just a healthy lifestyle but also a democratic one—in the sense that every resident could live under equally good conditions. The principle of serial rows of an optimized basic pattern was also in keeping with the demands of cost-effectiveness. In the years that followed, the row became increasingly popular in the hous­ ing developments of the Modern Movement—that process was not, however, nearly as linear and uniform as it might seem today, and it certainly resulted in solutions with local variation as well. In the mid-1920s, architects and theorists began to debate intently the proper orientation of the buildings and rooms in row houses and apartment buildings. The large developments in Germany that had been organized by the Social Democrats and many urban­planning reform projects occurred against the backdrop of such dis­ cussions. Soon it was considered good form to accompany plans for a residential building with diagrams of sunlight, lighting, and shading to demonstrate quasi-scientifically that the rooms and buildings were oriented properly. It should come as no surprise that soon opinions divided into two fundamental positions: On one side were the advocates of southern light, who argued primarily 58

ÿ

Ernst May, Building in rows scheme, 1930.—Strict orientation of the residential buildings along north–south axis.

ÿ

Perimeter block construction in Berlin, ca. 1900.

for maximizing sunlight in the apartments in winter. On the other side were the advocates of east–west sun, who tried to ensure that no part of the building went without direct sunlight. That means that all rooms—including, according to Otto Haesler, even stair­ wells and basements (!)—should receive at least some direct sunlight once a day. Both factions supported their beliefs with more or less convincing arguments and continually sought other, preferably scientific justifications for their principle. At the same time, a few voices were heard articulating a fun­ damental critique of the mechanical application of principles of orien­ tation and building. The advocates of such principles were accused of ignoring entirely parameters relevant to design, such as the ­location of the site, wind and weather conditions, specific require­ ments for the program, and aesthetic criteria. For example, the ­critic Adolf Behne not only questioned the urban-planning qualities of strict row construction but also found fault with a design process in which the apartment unit became the crucial point of depar­ ture: “Row construction tries to resolve and cure everything from the perspective of the dwelling. ... People have to dwell, and to become healthy from dwelling, and the precise diet for dwelling is prescribed for them right down to the details. At least according to the most rigorous architects, they have to go to bed facing east, eat and answer mother’s letters facing west, and the dwelling is ­organized such that de facto they cannot do it any other way.”5 Finally, in the 1950s, open row construction of multistory residen­ tial buildings gained acceptance as a common model used in ­particular for new developments and neighborhoods that had been destroyed in the war. The patterns and guidelines worked out by the Modern Movement continued to be the guiding principle, but the orientation question was no longer discussed with the same in­ tensity and dogged determination it had been before the war. Apart from a broad, growing skepticism about doctrinaire concepts, the reason for that was above all that taking the question of orienta­ tion into account in the planning process had long since become widely accepted. It was now just as taken for granted as a standard 59

nris

Sun

Su

set

North

e

se

i

un

nr

se

t

Su

S

Walter Schwagenscheidt, “Anordnung der Räume nach der Sonnenbahn” (Arrangement of rooms according to the course of the sun), diagram 1930.—Although this much admired diagram suggests an apartment should be oriented along an east– west axis, Schwagenscheidt always rejected an all too rigid application of a certain scheme to the question of orientation.

as, say, designing residences with built-in kitchens, garages, or ­elevators. At the same time, the aspect of sunlight and orientation had lost its “connection to modern architecture’s principle of ­equality and collectivity.”6 Consequently, buildings came to be in­ creasingly different and individual, not only in terms of the floor plan and building volumes but also with respect to the struc­ ture of the development. On the whole, the diversity of the ­solutions worked out from the 1950s and 1960s onward reflects a critical digestion of prewar trends—both in efforts to continue the development and attempts to create alternative models. Alongside a freer approach to row developments, the introduc­ tion of new types of residential building offered welcome accents and led to an articulation and loosening up of the city. From the end of the 1950s onward, the point-block or linear-block ­ high-rise quickly became very important in urban contexts, while more terrace buildings were found on the outskirts of towns and in agglomerations. Urban developing increasingly became a “collage of the current typologies for residential buildings, which are taken in the required portions and cleanly separated by type, then joined together to form ever new and yet usually very similar neighborhoods through which ‘the green flows.’”7 ­Often, however, the strict separation of residential, work, recreation, and transportation areas—in the spirit of the Athens Charter— in combination with the rigorously asserted functionalism of the building industry resulted in dreary bedroom communities and ­increased traffic, which encouraged sprawling overdevelopment. Increasing Density and Lighting: Rows, Blocks, and Towers From the 1950s onward, there was more and more talk about ­higher-density forms of housing. They were intended to make build­ ing as efficient and as economical with resources as possible and, from a social perspective, to encourage qualities that contribute to community. Experiments were carried out both with multi-

60

A. H. Steiner, Heiligfeld III housing ­devel­opment and residential high-rises at the Letzigraben, Zurich, 1950–56. Site, view.—The site, which Alfred Roth praised as the “most spacious new neighborhood in Switzerland,” is distinguished by a ­general loosening of settlement structures, a care­fully considered orientation of the build­ings, and differentiation of build­ ing heights.

story buildings and with forming larger complexes of single-family homes. High-density, low-rise construction should be divided into two different types of development. The new type consisted of residential developments of single-story homes with gardens. Often such developments were based on rectangular or L-shaped layouts with the houses staggered or lined up in rows in order to create backyards. This not only satisfied the desire to have the ex­ terior space related to the living space but also ensured the rooms facing the yard received adequate sunlight. The other type was a re­ discovered and refined low-rise row construction, in which the ­focus of efforts was on determining a layout for single-family row houses of two or more stories that would be optimal in terms of sunlight. Whereas the efforts in the first half of the twentieth cen­ tury to produce inexpensive and space-saving residences for ­working-class family had led primarily to rigid row constructions, now people tried to design more freely. In the 1950s there were a number of projects that worked with recessions and projections in the floor plan or twisted, staggered, and shifted the building vol­ umes—always focusing on optimizing the lighting situation for all the rooms. In addition, such ideas as forming banks or different levels were considered, after having played a rather minor role until now. Increasingly, architects came up with surprising solutions. Particularly in the case of dwellings with several levels, such as the row house, the use of the roof for lighting purposes resulted in ­nu­merous ways to increase considerably the incidence of light and the experience of space. For example, the shifting of roof pitches ­ or combination of skylights with two-story living rooms led to a distinctly improved distribution of light and also enlivened areas of the floor plan that would otherwise have been unattractive. Understood more broadly, the concept of higher-density forms of housing also included the multifamily homes in which a large ­number of standardized units are lined up next to or stacked on top 61

of one another, ranging from simple tiered buildings to elaborate complexes of rooms on several levels. For a long time, however, tall multistory buildings were still dominated by the linear, unarticu­ lated building form that results from stacks of identical floors, which was so familiar from prewar eras. Most of these followed a con­ ventional layout of corridor access, in which a limited number of apartments are accessed via a common stair landing. Whereas in a building with two units on each floor the units can face at least two directions, in a building with three or more units on each floor at least one of the units can face only one side. For that reason, larger numbers of units with deeper (and also narrower) floor

Atelier 5, Halen housing development, Herrenschwanden, near Bern, 1955–61. Jørn Utzon, Kingohusene housing ­development, Helsingør, Fredensborg, 1958–60. Site. Ulrich Löw and Theodor Manz, In den ­Gartenhöfen atrium housing development, ­Reinach, Canton of Basel-Country, ­ 1959–60. Floor plan of an atrium building, ­atrium with view toward living area.

plans tended to be accessed by an exterior side corridor or gallery, as that makes it possible for all the units to get light from both sides—albeit at the cost of privacy. One of the most famous examples of communal living in a multi­ story apartment building is Le Corbusier’s Unité d’habitation in Marseilles (1945–52). Integrated into a comprehensive concept of housing and social services, it includes maisonette apartments of various sizes. A system of access based on interior corridors on ­every third floor resulted in what is now called a “through-living floor plan”: units at right angles to the building axis that—on one floor, at least—face out from both sides of the building. The vertical soon emerged as an alternative to lining up units ­hor­izontally. As early as 1930, on the occasion of the third CIAM Congress in Brussels, Walter Gropius explored the question of the advantages and disadvantages of low-rise, middle-rise, and highrise construction. He discussed the suitability of each in terms of cost-effectiveness, urban planning considerations, the amount of open space, the amount of sun and shade. Gropius came to the ­conclusion that the residential high-rise came off best of these build­ ing typologies because it was “much airier, sunnier, and more ­private” and ensured a “maximum of green space” in which “above all children can live out their impulse to play and make noise 62

Arne Jacobsen, Søholm I “chain” housing development, Klampenborg, 1946–50. Floor plans of upper and lower story, section, view of dining area from living room balcony.—Ensemble with five slender, staggered two-story buildings. The space is differentiated vertically by means of a glazed dining area facing the garden seat­ ing area that extends upward to the shed roof; a stairway leads from the upper story to the large living room. The staggered arrangement of the shed roof provides additional light for the dining area and living room through a high ribbon window.

­ nhindered.” It was also “better in terms of cost distribution, more u hygienic, and more economical central facilities.” He even re­ commended that the individual national sections of CIAM “fight in their countries to ensure that the building of residential high-rises gets underway.”8 Although his own projects for building residential high-rises from this period were never realized, his appeal bore fruit: in 1932–34 the housing block De Bergpolder (Brinkman & van der Vlugt, Willem van Tijen) was built in Rotterdam, as a kind of prototype of the residential high-rise. In fact, however, the residential high-rise did not start to become more significant until the mid-1950s, in the form of the pointblock or slab-form high-rise. Its advantages—urban planning trans­ parency and at the same time high density—suited well the model of the articulated, more open city. In the case of point-block highrise, at least, the goal was usually to create as many small apartments as possible around an access and services shaft in the center or on the northern side. If the building exceeded a certain number of floors, however, the access area had to be nearly doubled to con­ form to safety regulations. That was an expense that only paid off if the number of apartments was large. When the depth of the build­ ing was too great, however, it worsened lighting conditions in apartments that open on only one side. Only the apartments in the privileged corner locations were assured of light from two sides. 63

Walter Gropius, Project for a slab-form high-rise, 1931.

The efforts to address the latent conflict between economy, l­ ifestyles, and high-rise design included creating high-rises in slab form with elongated floor plans and a system of access based on corridors. In this type of building—the most prominent example of which was already mentioned above: Le Corbusier’s Unité d’habi­ tation in Marseilles, with its wedged together maisonette apartments that always opened onto both sides—the principle of democratic distribution of light was given another chance. No matter whether the apartments were accessed via a corridor on the inside or the outside, the orientation of all the units was the same. Hence an east– west orientation was generally chosen for larger apartments and a southern orientation for smaller ones. Over time, large-format apartment blocks whose volumes dif­ fered little from one another began to characterize urban peripheries. Economic and constructional considerations justified such res­

Carl Auböck, Carl Rössler, and Adolf Hoch, Apartment blocks, Vienna-Leopoldstadt, 1959–62. Axonometric drawing.—The ­same conditions for all: The orientation of the housekeeping and storerooms to the north as much as possible, with the living and common areas facing south. The living rooms of all the apartments have generous windows to the south and open up to the outside with loggia-like balconies. The balconies are conceived as natural sun shading, since they block the path of the noonday sun when it is high in the summer sky. At the same time, they permit ­direct sunlight when the course of the sun is lower in the sky in winter.

Harry Seidler, Victoria Tower Apartments, Potts Point, Sydney, 1962. View, floor plan of living story.—Eight-story apartment building with four units per floor. Each apartment is lit from two sides and has a large window facing either the ­harbor to the west or the park to the east.

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idential buildings as a pragmatic means to meet the rising demand for housing during the boom years. At the same time, there were also more attempts to break up the compactness of the self-con­ tained, often monotonous-looking building volumes and give them more plasticity. Such efforts ran in two directions. Terraced buildings were a special example: thanks to the staggering of the floors, the amount of natural light in the individual apartments was greater than vertically stacked multistory buildings. Partic­ ularly in apartment blocks accessed from a single point, the linear layout of the floor plan was broken up. Thanks to forms that often reached out into the external space in expressive ways, it be­ came possible to create units with new spatial characteristics and qualities, especially with regard to the supply of natural light. Famous examples include the Romeo & Julia residential highrise in Stuttgart-Zuffenhausen (1959, Hans Scharoun) and Alvar Aalto’s fanlike Neue Vahr residential high-rise in Bremen (1958–62). Otto H. Senn demonstrated with particular rigor the move away from the rectangular and the qualities of a polygonal floor plan: in his residential building at Interbau 57 in Berlin (1957) and later the Hechtliacker high-rise in Basel (1962–65, together with Walter Senn). In both these residential buildings, the living and dining ­area joins with the balcony to form a corner of the building that is lit from two sides. Despite the at times less than optimal orientation of specific rooms, and the placement of the wet cells in the interior of the apartments, such solutions had one crucial advantage: all the apartments open in at least two directions.

Fritz Stucky and Rudolf Meuli, Terraced buildings, Zug, 1957–60.

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During the decades-long debate over the question of orientation and the principle of the opened city, the site itself and the urban plan­ ning context tended to be ignored. During the last third of the twentieth century, the urban planning shortcomings resulting from the neutrality of an open green space that connects everything— namely, the loss of differentiation between open areas of encounter and semiprivate rooms for retreat—became obvious. The end of the high-rise euphoria in the 1970s went hand in hand with a new turn to exterior space as social space and hence with an effort to de­ velop building forms that support such spatial connections. Rather than focusing on solitary building volumes such as pointblock or linear-block buildings and how much sunlight they ­provided in individual units, the latter were once again made func­ tionally dependent on the urban planning conditions. With this return to an urban planning that shaped space, innercity block construction enjoyed a renaissance. After years of parity among all sides of the building, there was a return to floor plans that distinguished between front and back. Unlike in the late nineteenth century, however, it was no longer the street that pro­ vided the crucial reference point for space but rather the quieter side facing the courtyard. The new search for urbanism influenced the question of spatial orientation to the extent that the individual functions of living were no longer organized exclusively around optimal sunlight but also around criteria such as their relationship to public and private exterior spaces. What began to emerge with that—namely, the insight that the question of orientation is an ­integrative component of an overarching, complex set of demands— resulted in a number of interesting projects over the years that ­responded inventively to the question of different orientation re­ quirements and relationships to exterior space.

Modulation of floor plan and building ­volume: Alvar Aalto, Neue Vahr residential high-rise, Bremen, 1958–62. Otto H. Senn, Interbau 57 apartment ­build­ing, Berlin-Hansaviertel, 1957. A.H. Steiner, Residential high-rises at the Letzigraben, Zurich, 1950–56.

BKK-2, Sargfabrik residential complex, ­Vienna-Penzing, 1993–96. Courtyard.

In Healthy Light: Balconies, Loggias, Terraces For potential home buyers, the garden continues to be one of the most important factors. Similarly, in surveys of what people desire in apartment buildings, private exterior space always ranks very highly. Evidently people are driven by eternal desires to garden and live outdoors. What solutions can apartment buildings offer to re­ place the open spaces that make a free-standing single-family home so desirable? Where can an urban plant lover find enough space to grow flowers, bushes, and even trees? The keyword here is roof garden. Ever since cities have existed, and with them town houses that grow ever taller, vegetation has been rising with them: from the sparse backyard garden in troughs and tubs to roof gardens and projections of all kinds. Something that still posed a technical and financial challenge in the era of the Modern Movement, the flat roof that can be used as a terrace, has long since become standard, thanks to appropriate building materials and technologies for ­reinforcing. This has resulted in a promising alternative to the flow­ er window as the lowest common denominator of home gardening. The crucial opening for the expansion of living space came once again from the protagonists of the Modern Movement: daylight and sunlight were not only supposed to stream into living rooms through generous panes of glass but also, thanks to the immediately adjacent exterior space, have a direct effect on the body. Such is­ lands of recreation—the private garden or terrace in the case of a

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single-family home or balconies, loggias, and later winter gardens in the case of multistory apartment houses—became increasingly sig­ nificant over time, offering modern contemporaries appropriate space for extended fresh-air or sun bathing or outdoor gymnastics. Such concepts as closeness to nature, health, beauty, and youth turned up in the relevant publications and manifestos, accompanied by photographs and sketches that invited residents onto balconies and terraces for a relaxed life in the open.

Open-air living in the Neubühl Werkbund housing development, Zurich, 1928–32.— “Today we need a house whose structure is in harmony with a physical feeling that has been liberated by sports, gymnastics, and a sensible lifestyle: lightweight, permeable to light, mobile.”—Sigfried ­Giedion, Befreites Wohnen (1929).

Since the end of the 1920s, building volumes have been composed from cubes shoved together, and their obligatory flat roofs clearly cried out for outdoor living. And progressive housing concepts for multistory apartment buildings also soon added balconies or ­loggias for a corresponding architectural gesture on a small-scale. Once reserved for appearances by the nobility and indebted to the bourgeois urge for self-presentation, the balcony experienced a radical reevaluation by the generation of the housing reformers: it mutated from being the standpoint of the elite voyeurs to being an instrument of light, air, and sun hygiene for everyone. The balcony thus became the first attribute of bourgeois living that was added to the working-class apartment: “the first crossing of a boundary out of the minimized interior, the first peripheral element of the ­apartment occupying an entire floor,” as Gerhard Auer has called it. However, its job profile was overburdened from the beginning: ­everything that until then could be experienced without restrictions all the way to the neighbor’s fence in a private residence was sup­ posed to be possible on just the few square meters of a balcony. It had to be vegetable and flower garden, sun terrace, garden arbor, and ­children’s playground at once and still provide sufficient view of the surroundings—without the possibility of looking in. Under the strict aesthetic control of the architect’s eye, a minimum scale of ­ersatz open space was defined. The minimum standards proposed in Ernst Neufert’s Bauentwurfslehre soon did one last thing to ensure that most solutions for the balconies of apartment houses would remain unconvincing. Most solutions did not even have sufficient room for a deck chair, and during the building boom that began in the 1960s, undersized balconies in a striped pattern became the

Le Corbusier and Pierre Jeanneret, Project for Immeubles-villas (apartment housing blocks), 1922–25.—They were the prototype for a number of attempts to stack ver­­­­ tically two-story row houses with a ­garden.

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Herman Hus, “Mali neboticˇnik” [Small skyscraper], Ljubljana, 1931.—The corner of the building effectively emphasized by means of rounded balconies.

Balcony, 1950s.—Such minimal solutions are suited at best as additional storage for cases of beer or trash cans. Balcony idyll in the 1950s.

trademark of thoughtless and faceless stacked apartment con­ struction. As a consequence, the balcony, having been robbed of its real meaning, was reduced in many places to a (admittedly much needed) storage area for bicycles, cases of beer, or garbage cans. Even today there are enough examples to demonstrate that the concept of the balcony has been flogged to death. From the outside, the balcony’s hollowed-out sister, the loggia, has enjoyed a better career. As an architectural framed open space, which merely lacks windows, its essence is closer to that of an interior than an exterior. Protecting the facade of windows inside, and at the same time offering a comprehensive prospect outward, it creates an intermediate space that communicates between both worlds. These days loggias are common, especially for apartments and maisonettes, and sometimes extend the full length of the ­facade. With its technological aids for light, sight, and weather— such as sliding shutters—it has made an essential contribution to the metamorphosis of the facade and now determines the exter­ nal appearance of apartment buildings. Because of the lighting problems caused on the floor underneath when balconies or loggias are too deep, in several projects exterior areas attached to the apartment were dispensed with in favor of communal roof terraces. Only comparatively late, and in no small measure as a result of criticism of “inhuman” high-rise buildings, the possibilities of terraced apartments were explored. This building type, which offers residents not only a private outdoor space but also direct contact with sun, rain, and wind, had already been re­ flected on during the first third of the twentieth century, and ­several examples were built. Around 1900 such pioneers of ferro­ concrete construction as François Hennebique, Auguste Perret, and Henri Sauvage worked out projects that foresaw terraces as fullfledged outdoor spaces. Soon thereafter the terraced building was considered a forward-looking model that could translate the idea of the garden city to the vertical. Consequently, there were nu­ merous such projects proposed in the circles of reform-minded ­architects: as early as 1900–1905, Tony Garnier created a vision of a city of terraced buildings in his Cité industrielle. In 1914 the 70

Vladimír Fischer, “Švédský du˚m” [Swedish house], Apartment house for Fritz Schmeer, Brno, 1909–10. Facade with loggias. Max Schönenberg & Partner, Am Eschenpark residential building, Zurich-Neu­Oerlikon, 2003–4.—Trendy urban living behind a loggia facade with sliding shutters.

Italian Futurist Antonio Sant’Elia followed with his project for a Città nuova. Henri Sauvage’s Immeubles à gradins were other close relatives; he began to develop them prior to the First World War, and two of them were even realized in Paris. Adolf Loos also turned his attention to the possibilities of the terraced building. In 1912–13 he was already putting terraces on both upper stories of the Scheu House in Vienna’s Hietzing district, thereby introducing the stepped form typical of the volumes of terraced buildings. With their weakness for the flat roof, the protagonists of the Modern Movement also had corresponding fantasies for the roof and terrace designs—for example, J. J. P. Oud, Hugo Häring, Richard Döcker, or Le Corbusier and his project for the Durand apartment house in Algiers (1933–34). 71

Le Corbusier and Pierre Jeanneret, ­Immeuble Clarté, Geneva, 1930–32. View from the roof terrace toward Geneva and Lake Geneva.—The modernist roof terrace as site of physical fitness and sun worship. Le Corbusier, Unité d’habitation, Marseilles, 1945–52. Roof terrace. Henri Sauvage, Terraced apartment build­ ing (Immeuble à gradins), rue des Amiraux, Paris, 1922–26.

Finally, the terraced building became the favorite building type of the housing utopians of the 1950s and 1960s, whose projects with funnel, container, and conic forms always presumed a terraced structure. Two pioneering projects can be considered milestones of terraced living: the Halen housing development near Bern (Atelier 5, 1959–61), and Moshe Safdie’s Habitat housing modules at Expo 67 in Montreal. Almost overgrowing with green today, both became the point of departure for numerous solutions for ter­ raced buildings, especially in Switzerland, where limited space and the topography provide ideal conditions for terraced residential buildings. Despite their known weaknesses—poor integration into the urban fabric, the monotony of the layer, lighting problems caused by deep floor plans, problematic rear or inner sides, prob­ 72

Walter Jonas, Project for a “spatial city” with Intra Houses, 1958–60. Atelier 5, Halen housing development, Herrenschwanden, near Bern, 1955–61. Housing units with roof terrace.

lematic energy use resulting from large surfaces—the architectural form of the terraced building has been increasingly appreciated, precisely because it can offer unrivaled exterior space, can be imple­ mented in various ways, and can offer a real alternative to the ­unplanned sprawl of single-family homes. Continuing to Build with Distinction Row or block? In the 1920s that was an ideological question. Today, by contrast, the effort to come to terms with urban space is marked much more by the design aspects of shaping space. This in­ fluences the question of the orientation of space in that now the

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Continuing to build in the city: BKK-2, Sargfabrik residential complex, ­Vienna-Penzing, 1993–96. Courtyard with smokestack of former coffin factory, floor plan.—Multiwing, high-density residential structure with free spaces for ­various uses and shared facilities that can also be used by the neighbors. The ­maisonette apartments are arranged in a north–south direction, accessed by ex­ terior corridors, and can be designed individually by occupants; they have access to private exterior space (balcony, terrace).

Row of buildings on Scheepstimmermanstraat, Amsterdam-Borneo Sporenburg, Borneo eiland, 1999–2001. View, axonometric drawing of the residential building at no. 18 by MVRDV.—New living in a ­former port facility: Although the occu­ pants can design their buildings individually, the unity of the row is preserved by means of complex connections to the ­exterior.

Burkhalter + Sumi Architekten, Multifamily villa, Zurich-Witikon, 1998–2002.

i­ ndividual functions of dwelling are no longer organized exclu­ sively by the principle of optimal insolation. In any case, today we start out with entirely different premises when designing floor plans for residences. The functional differentiation of individual rooms may have been justified in the modernist era based on prevail­ ing economic and social conditions. Today, with the standard of living having risen in general and lifestyles having become more plu­ ralistic, there is instead an increasing call for neutrality of use in ­order to do justice to changing housing needs. Together with one of the crucial criteria for housing quality—having the apartment face a private outdoor space—this has led to floor plan layouts and spatial solutions that interpret the question of orientation and ­lighting more flexibly. Another issue in this context is the goal of supposedly optimal, bright lighting values. Many planners still presume that the illu­ mination of a room should be as homogeneous as possible. In fact, however, change is the reality of light’s nature. We have long known that any stability of light is unnatural, and only change revi­ talizes us. For that reason, rather than standardized brightness, the diversity and changeability of light should be a quality sought in every design. That necessitates an early and thorough consideration of lighting conditions, such as changes in the sun’s position and the course of shadows. As far as sunlight is concerned, the primary focus today is on how it works psychologically. The physical origin of the need for sunlight in interiors has long become less significant as a result of improved hygienic standards. Nowadays, however, ecology seems to have taken over the role that hygiene played for the modernist era, putting the question of the proper orientation of buildings in a new light, not least because of the rise in floor space used and cor­ responding energy consumption. In contrast to those days, it is less about quantity than the right time for solar radiation. It is, how­ ever, just as much a mistake today as it was around 1930 to want to 76

insist on strictly maintaining a given orientation simply to optimize a single aspect. More recent studies have made it clear that orienting a building and opening it up completely to southern exposure is only effective in reducing energy if it is located at least 700 meters above sea level. Nor can one make any universally valid statements about the modulation of building volumes. Already in the design phase, the architect is confronted with fundamental conflicts among objec­ tives: Whereas a compact volume is necessary to keep heating ­requirements low, an articulated volume often has considerable ad­ vantages in terms of natural light. Hence whether it pays when the course of the facade is increased by employing notching, fanning, or rounding of the building volume depends on the specific situ­ ation and ultimately has to be estimated individually. Moreover, the provision of sufficiently attractive exteriors is an important influence on designing a facade. In an age when work is becoming increasingly flexible and leisure time is becoming an in­ creasingly important consideration for housing, immediate access to a private outdoor space is an essential criterion. Dispensing with regular cross sections of the building in favor of greater ­diversity of location is encouraging the development of types of housing that can transfer the qualities of living in one’s own home to apartment living. In fact, there seems to be a greater awareness again today—often with corresponding earlier types in mind—of the areas around the home, and with it a conviction that it is precisely the potential for designing these transition zones between inside and outside oneself that makes a home worth living in. Outdoor living should not last just long enough to smoke a cigarette or snip ­something from the herb garden; it should be a true extension of the living room.

1 Fritz Wichert, “Die neue Baukunst als Erzieher,” Das neue Frankfurt 2, nos. 11– 12 (1928): 233–35, here 235. 2 Walter Gropius, “Die soziologischen Grundlagen der Minimalwohnung (für die städtische Industriebevölkerung),” Internationale Kongresse für Neues Bauen, ed., Die Wohnung für das Existenzminimum: Einhundert Grundrisse, 3rd ed. ­( Stuttgart: Julius Hoffmann, 1933), 13–23, here 19. 3 “Die Werkbundsiedlung Neubühl in Zürich Wollishofen,” Das Werk 18, no. 9 (1931): 257–79, here 260–61. 4 Hans Bernoulli, “Neuere Basler Wohnhausbauten,” Das Werk 9, no. 9 (1922): 113– 22, here 113. 5 Adolf Behne, “Dammerstock,” Die Form 5, no. 6 (1930): 163–66, here 164. 6 Peter Faller, Der Wohngrundriss (Ludwigsburg: Wüstenrot-Stiftung; Stuttgart: Deutsche Verlags-Anstalt, 2002), 93. 7 Ibid., 93. 8 Walter Gropius, “Flach-, Mittel- oder Hochbau?” lecture at the third CIAM Congress in Brussels, November 1930, reprinted in several publications. Quoted here from Das neue Frankfurt 5, no. 2 (1931): 22–34, here 34 and 33.

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Light, Sight, Space Experiencing Light, Perceiving Space, and Looking Out

Meili Peter Architekten, Staufer & Hasler Architekten, Residential building, cinema, and bistro RiffRaff, Zurich, 1999–2002.

Light and Sight The increased importance attributed to daylight in the early ­t wentieth century had far-reaching consequences for living space and its interface with the outside world: the window. Natural light was no longer considered aggressive or harmful; on the contrary, it was almost granted the status of a panacea. Window ­coverings that had been common until that time would disappear as relicts of an age hostile to light. Instead, the expectations of a ­window were now determined by good ventilation and unrestric­t­ ed entry of natural light as well as an increasing need for an open view of the surroundings. This desire for light and sight led to spirited and sometimes controversial discussions about the ­funda­mental functions of a window as well as to new solutions, with corresponding effects on the interior and the exterior ­appearance of buildings. The cultivation of the function of views outward, which began with the bay window, continued with ever larger wall ­openings, to the point where it was no longer possible to say with certainty what was the window and what the wall. The prospect has from the time it was cultivated always had a hint of exclusivity and luxury about it. A suitable building site and the use of glass, an expensive material, were crucial and limited uses to, with few exceptions, villas, single-family homes, and apartment buildings for the luxury market. Le Corbusier, for example, became very interested in designing his buildings as true machines for seeing. By contrast, the prospect as a factor in the common apartment building is limited to the installation of so-called panora­ ma windows, although, unlike with a well-heeled clientele, here they are less about a splendid prospect or visual effect than about a virtual extension of the ungenerous living space into the exterior. This social distinction—which to a certain extent may also be rooted, to various degrees, in an openness to changes in the living space—reveals at the same time the limits of modernism’s ideas of social reform. In public housing, for example, which was subject to more stringent financial conditions, certain compromises had to be accepted. That meant first and foremost: light for all, views for the few. Today this distinction has long since been mitigated. Or perhaps only apparently? “Wall versus opening is the basic theme of every architectural space; it points beyond purely functional

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Whereas interiors were previously con­ ceived as self-contained volumes into which light fell through few windows as holes but muted by opulent curtains usually of dark fabric, the living area increasingly evolved over the course of the twentieth century into a bright, open area with fluid boundaries and generous natural light. Apartment, Berlin-Steglitz, 1890s. Otto Senn with Rudolf Mock, Zossen apartment building, Basel, 1935–38. Living room. Richard Neutra, Case Study House No. 20 (Bailey House), Pacific Palisades, CA, 1947–48. Living room. Lacaton & Vassal, Residential complex, ­Floriac, Gironde, 1999–2002. Visualization.

r­ equirements. The relationship of wall and opening is, so to speak, a parameter for the social, cultural, and technical standard that a building possesses or imploringly seeks to claim.”1 But now more than ever, contemporary residential architecture implies enormous windows. Yet more and more occupants turn out to be astonishingly flexible: people have come to terms with changing fashions and avant-garde design. The expectations of what people want to see have also changed. In an age when cities are once again expecting a large influx of residences, among true “urbanites,” a view of a more or less exciting urban and industrial landscape is just as popular as an unobstructed view of nature once was. Between Inside and Outside As the interface between inside and outside, the window has to ­fulfill a daunting set of expectations. In addition to providing the ­interior with sunlight, the window also has to ensure ventilation and regulate the exchange of coldness and warmth. Similarly, it plays a central role in controlling access to the outside world. We are ­inter­ested primarily in the factors that are tied to the window’s visual permeability: the window as, on the one hand, a source of natural light and, on the other hand, as an opening that permits a visual ex­ change between inside and outside. The dialectic of these two ­factors has influenced the window for centuries—far beyond such ­f undamental technical and design problems as protection from the sun or glare that have to be solved within the tension between light and sight.

“Classical”: Vertical window with main window and storm window and muntins.

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Paul Wolff, Winken (Waving), ca. 1936.— The window as a place of visual communi­ cation. Michael Sowa, Februar.—Windows pro­ vide information about what is happening outside one’s own four walls.

Meili Peter Architekten, Staufer & Hasler Architekten, Residential building, cinema, and bistro RiffRaff, Zurich, 1999–2002. Desk with view of courtyard.—The pros­ pect as temporary distraction.

Building means creating boundaries; the distinction between inside and outside is associated with that. Every element between an inside and an outside produces a dual relationship; it can emerge as a separation or as a connection, is both distinction and transition, boundary and conduit. The window is thus primarily a border area that communicates “between inside and outside, security and danger, familiar and strange, between finiteness and expanse, ­attachment and freedom, reality and illusion.”2 Depending on the design and formulation of this threshold situation, the window can refer to the character and value of the universe that lies beyond it. In other words, the size of the opening and the quantity and quality of the daylight it admits is also a highly differentiated measure for the various individual and social ideas of value (and living) that depend on the cultural context. Looking Out: Information and Contemplation Since the twentieth century, the prospect has turned out to be the true key function of the window in Western culture. It is of great importance to the subjective assessment of a spatial environment by its users. It need not even be an opportunity for a sweeping panorama of a picture-postcard idyll, even a fleeting glance through a small window to an enclosed residential district is ­sufficient to contribute to a feeling of well-being in a room. On the one hand, this is because of the factual information that a view of the exterior provides. Ultimately, that is based on a biologically verifiable human need for security, a desire to be informed

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about one’s surroundings. What is the weather like today? Who is ­approaching the building? Who are the children playing with? All these are questions that play an important role in everyday life. Even when, as in the case of a skylight, no direct visual contact with the landscape results, varying light and weather conditions over the course of the day or the perception of noises and the effects of warmth and coldness perceived through the window help us to anchor ourselves within our living environment. By contrast, if such information is lacking—in a windowless room, for example— the situation will quickly be perceived as unnatural and oppressive. In addition to this rather functional level, there is, however, also another, emotional level on which the outside world transforms into the counterpoint of one’s own reality, so to speak. Thus a view of surroundings that are essentially different from one’s own four walls can not only offer a temporary distraction but can also have a stimulating or relaxing effect—for example, a brief look at a busy street or an atmospheric sunset. The Window’s Loss of Importance In contemporary architecture, the window has become the fossil of building. Architecture is marked by a tendency to transform the window into a wall. That has not failed to influence living conditions, since whereas the window as hole “seen from inside, cuts manageable, bearable parts out of reality with which a dialogue becomes possible,”3 the glass wall, by contrast, brings the outside world into the immediate proximity. Unlike the traditional win­ dow, which is intended to be an eye onto the world but also to offer protection and security, the focus today is on visual sensation and hence optical transparency: dwelling as a technology of ­observation. Taking the environment, the entire outside world, into the interior of a room finds its profane limit where the world no longer rewards the effort. Whereas “large windows with opportunities for unobstructed panoramas” were once intended to give people a feeling of “relaxation, contentment, and relief,” as Richard Neutra put it, today a looming world of concrete impedes our view outward. In most cases, however, the latter also implies a view inward, which is why people have been preoccupied for more than a half century with eliminating this “deficiency.” In this context, it has rightly been remarked of designing a window: “On the one hand, it cannot be large or wide enough, like the ­panorama window of the 1960s; on the other, it is veiled and covered. On the outside with plants and on the inside with curtains.”4 We are still anxious about the exhibition of our homes, for the ­mental exercise apparently requires much more time than the ­practical one. Wherever the greatest physical opening reduces the wall’s share in favor of a completely different relationship between inside and outside, the original function of the window as a mediator between natural daylight and the built spaces is lost. Lighting ­becomes an indefinite and vague quantity that, paradoxically, can only be controlled by covering the intended prospect. The modern will to build thus cancels itself out, as it were, and the tactile and sensual wealth of the interior—which the architect and ­cultural theorist Adolf Loos could once produce like no other—­ is drowned in overexposed, dreary shadowlessness.

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Bonnard+Woeffrey, Residential and studio building, Monthey, Canton of Valais, 2002–3.—Window or wall? Flower window.—Almost as soon as large windows became established as a feature of residential buildings as well, they were decorated with plants and curtains.

For Loos, for whom comfortable living and coziness were a­ lways the dominant concerns, windows were tailored entirely to the conditions of the given interior or their significance as sources of light. Where no windows were needed, large sections of closed walls could result. With the almost exclusive concentration on the window’s function of providing light, and the associated reduction of the visual sensation of the interior, the materiality could emerge in tangible sensuousness. Loos may generally be viewed today as a pioneer of functional architecture, but in relation to the importance he attributed to the proper lighting of the interior and to the window, he was very much rooted in nineteenth-century ideas of bourgeois housing.5 In a little noticed passage in his book Urbanisme, no less an authority than Loos’s colleague Le Corbusier noted in retrospect: “Loos assured me one day: ‘A man of culture 85

does not look out of the window; his window is made of frosted glass; it is there only to provide light, not to let the gaze out.’”6 The design of the windows and their immediate surroundings in Loos’s interiors followed this principle. Nearly always the windows had curtains or were made of opaque glass, which, on the one hand, prevented any view out and, on the other, provided an extreme­ ly subdued natural light. Moreover, the spatial organization and the placement of the built-in furniture usually prevented direct access to the window. Often, for example, a sofa or seating niche was placed right under it, so that the person sitting on it turned his or her back to the outside world and had to face the room. As late as 1930–32—in his duplex apartment in the Vienna Werkbund housing development, whose two-story living space with generous windows truly seemed to follow the latest trends—Loos placed an exposed corner seating unit on the gallery, with the backs once again facing the large window. A closed-off space and an intro­ verted gaze constituted Loos’s ideas of a comfortable, cozy, homey living environment. Throughout his career, Loos distanced himself from the demands for unrestricted and immediate visibility emerging at that time. The interior was supposed to provide an intimate and familiar stage for private life shielded from the outside, while an overlapping with city life ran counter, in his view, to civilized urban behavior. Consequently, he saw the window as a deliberate barrier between inside and outside and in practice reduced it to its function as a source of natural light. His design for a bay-window-like oriel in the dining room of the Kraus Apartment in Vienna (1905) also followed this maxim.

In Adolf Loos’s residential buildings, the sofas and seating niches are often placed under a window facing the interior, so that ­occupants turn their backs on the out­ side world: Eisner Apartment, Plzenˇ, 1929–1930. ­Dining room. Brummel Apartment, Plzenˇ, 1929. ­Bedroom. Kraus Apartment, Vienna, 1905. Bay win­ dow in the dining room.

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Nevertheless, the view out of the private living environment into the surroundings also became a theme in Loos’s work, as is ­ev­ident from the Kuhner Country House in Payerbach (1929–30). There he opened up the living room onto the Alpine surroundings of the Semmering region with a three-casement window wall. In addition, Heinrich Kulka’s monograph on Loos, published in 1931, includes a view of the smoking room of this same country home with an open view into the surroundings.7 Thus Loos produced two veritable panorama windows that entirely broke open the intro­ verted atmosphere of the space. The interior was optically expanded—a typical concern of modernism that until then Loos had only taken into account in his interiors with deliberately placed mir­ rors and differences in level. Admittedly, the Kuhner House was built in an Alpine landscape and not in the urban environment char­ acteristic of Loos’s other buildings. What could be more natural than dramatizing the view of Alpine beauties for the harried city dweller?

Adolf Loos, Kuhner Country House, ­Payerbach, Lower Austria, 1929–30. Living room. Photomontage of the view outward: In Heinrich Kulka’s monograph on Loos— Adolf Loos: Das Werk des Architekten ­( Vienna: Schroll, 1931)—the study opens up on the valley (top), whereas in fact its prospect is of the far less spectacular slope (bottom).

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Apartment, Berlin-Steglitz, 1890s.—The bourgeois apartment as a space for ­withdrawal, protected against the outside world.

The Spatial Box: Discretion in Muted Light Changes in the conception of architecture and its design and function are, no more so than innovative conceptions for space, not something that is invented but instead result from the interaction between architecture and a specific cultural and social context. ­Otto Friedrich Bollnow wrote in Mensch und Raum (Man and space) in 1963: “There are different forms of sensing space, and they are closely connected with how people feel about life in general.” In fact, however, looking at the last 150 years of architectural history it is clear that the changes in society were not limited to per­ ceiving and designing the spatial environment but were always also manifested in a particular relationship to the window as interface and to the relationship of lighting and prospect. The idea that windows were supposed to provide an interesting or even spectacular prospect is a twentieth-century phenomenon. For nineteenth-century bourgeois homes, it was, as a rule, not a mat­ ter for discussion. At that time, architecture was seen primarily ­ as a technical problem of form that concerned finding the appropriate stylistic expression for a given architectural task. Discredited in retrospect by modernist architects as an empty architecture of facades, at that time the material appearance of the building was the center of interest for architecture, while the spaces behind it had to adjust to the needs of the exterior. The central idea behind the bourgeois home was a space for withdrawal protected from the outside under the primacy of the private. As the stronghold for ­fa­milial activity and for displays of status, bourgeois homes repre­ sen­ted the opposite pole of the anonymous, public world of work with its precisely defined rules for social behavior. In view of the effort to shield off the intimate living area as much as possible, windows seemed like weak spots, as it were, where someone ­standing outside can catch a glimpse of the interior or where excessive daylight could disturb the peaceful atmosphere. Vertical ­window formats, jammed between pillars and wall projections, were thus covered with several layers of curtains so that they would fit in harmoniously with the eclectic Gesamtkunstwerk of the latenineteenth-century bourgeois home.

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In this way the window evolved by the end of the nineteenth century into what Wolfgang Schivelbusch has called a “highly ­differentiated light trap,” with curtains and drapes inside and venetian blinds, roller blinds, awnings, and shutters on the facade. The focus was thus not on letting light in but on defending against something perceived as aggressive and blinding. Natural light should only enter the interior indirectly and thus discreet and muted so as not to disturb the homey atmosphere of the space. All effort was made to preserve the material value of the carefully composed interior furnishings. For that reason, as can be read in ­numerous contemporary descriptions, a north-facing apartment was considered a “blessing” as then things “would not fade.”

Bay window of a residential building, ­Amsterdam-Zuid.

The Framed View The landscape paintings in bourgeois living rooms that suggested a view out a window could be seen as the first sign of a nascent need for a prospect. This sublimation did not seem to work in the long run, however, since the desire for a real look out of one’s own four walls soon began to give way to well-protected, closed-off space. One development in this direction had already occurred in the eighteenth century with the introduction of the bay window in Anglo-Saxon architecture, which soon became a widespread ­feature of facades. M. H. Baillie Scott described its advantages over conventional, vertical window formats: “The function of the ­ bay-window is chiefly to enlarge the range of prospect and aspect in a room. By this means a window on an east or west front may ­admit the southern sun or display a view to north or south which might otherwise be lost. ... [Bay windows] also have their uses in extending the floor-space of the room. They may often be fitted with a window-seat.”8 Later Josef Frank too would call attention to the supposedly advantageous psychological effect of this sort of window: “I would surely consider it important that each living space have windows in all directions of the world in order to avoid a feeling of being closed in. That is almost always possible, and when it isn’t, it is possible to suggest it symbolically by means of small additions; that was the significance of the bay window.”9 Otherwise the openings were arranged such that they were in the line of sight of a viewer standing in the middle of the room. That way someone in the room could get a picture of the outside world without having to move about the room. This static concept of space reflected the spirit of the time—a time when it was thought that man was the center of the universe. The closed character of an interior with a few openings in the wall may have limited visual ­freedom, but the restriction of the field of vision also permits the reassuring thought of withdrawing from the world. The opening of the living area that would be advocated by the representatives of modernism was prescribed much earlier by art. Even today, the subject of the window opening as a place of human exchange, as a silent communicator of views in and out, continues to be a popular motif in literature and above all painting. Again and again, depictions of windows, with or without people, symbolize the dreamy, fairy-tale-like, or contemplative character of the prospect. The window pulls the world far away and creates proper and conscious distance. It is the inspiring “borderline between two antithetical spaces, the place of present situation and the place

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Caspar David Friedrich, Woman at the Window, 1822. Oil on canvas, 44 x 37 cm. Alte Nationalgalerie, Staatliche Museen zu Berlin.—The window as a place of con­ templation.

of yearning,” as Bruno Reichlin has written. In fact, most of these paintings of windows were made at a time when the culture of housing was still characterized by a far-reaching separation from everything outside. Thus nineteenth-century painting, especially German Romanticism and late Romantic Biedermeier, ­represented a golden age of window scenes. A welcome reference for such works was provided by the numerous interiors in seven­­teenth-century Dutch genre painting, with their love of detail and effective depictions of natural-light streaming. These scenes usually show one or more figures, preferably women, engrossed in silent activity, standing near a window as a source of natural light. Whereas the poetry of the Dutch works was based primarily on order, silence, and the subtle handling of light, the later ­re­miniscences expressed much more the diversity of emotions of the people near the window: the window as a place of internalization and reflection, as a place for the lonely person to give free rein to thoughts and feelings such as homesickness, wanderlust, and desire or to dwell on a secret love.

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Joseph Paxton, Crystal Palace, Great ­E xhibition, London, 1851. Photograph of the interior of the building, which was ­dismantled after the Great Exhibition and then reconstructed in Sydenham from 1852 to 1854.

Bursting the Box: New Spaces of Experience As the architectural foil to the stronghold of the private, new building types such as train stations, market halls, exhibition halls, and arcades were developed in light iron-and-glass constructions as public, autonomous living spaces. It must have been the effect of this comparatively free—and liberating—spatial atmosphere that later led Walter Benjamin to characterize arcades as the “mold in which modernity is cast.” Although light-filled rooms with glass facades first seemed appropriate only for public buildings, it ­a lready hinted at the beginning of a general change in perception that from the mid-nineteenth century affected broad spheres of life and ultimately also found expression in a changed conception of space. Two developments in particular had a lasting influence on the relationship of humans and their environment and hence the idea of space in the nineteenth century. First, there was the train, which made it possible to experience a new dimension of speed, which went hand in hand with a vexation of the previous sense of space and time. It was not just that places that until now had seemed far apart moved close together, but the space in which one traveled became more dynamic to perception and thus transformed into a rapid ­sequence of blurry and fleeting images. Second, technological devel­ opments in civil engineering employed in the public buildings just mentioned led to a transformation of architectural values that had been considered valid until then. With the new use of iron as supporting material and glass as filler, the hitherto common impression of a demarcation by solid walls disappeared in favor of an imaginary boundary in glass. At the same time, construction began to dominate and became the fundamental bearer of archi­ tectural expression. One example that would set new standards was Joseph Paxton’s Crystal Palace at the Great Exhibition of 1851 in London. The nearly 600-meter-long building became epoch-making not only for its clear and rational solution to the architectural brief of using the new materials of iron, glass, and some wood but also for new effects of its space. Retrospectively, an author wrote of this space, which inspired in visitors an “astonished admiration of its uniqueness”: “This space had something liberating about it. In it one felt protected and yet un­inhibited. One lost any awareness of gravity, of one’s own sense of being physically tied down.” Above all it was the lack of familiar light and dark that apparently left such a radical impression. The presence of a single, unarticulated space lit without contrast was con­siderably vexing to the visitors’ sense of space and orientation and turned their estimates of dimensions into an uncertain game: the shadowless brightness evoked in visitors associations with a ­limitless space.

It was ultimately the still young field of art history that in the late nineteenth century ceased to judge architecture on the basis of classical principles and sought instead to establish its true essence in space. At the same time, this turn to space represented a dis­ sociation with the idea of architecture as the art of the facade that had characterized historicism. It was supported by new theories in the philosophy of perception, which had shown that there was no ob­­ jective reality but rather that reality was always “homemade” by the observer: it was not that things themselves had emotional quali92

Adolf Loos with Karel Lhota, Villa Müller, Prague-Strˇešovice, 1928–30. Hall, view from northeast.

ties; it was the subject that attributed such qualities to them. ­Cor­respondingly, the art historian August Schmarsow, in his “Das Wesen der architektonischen Schöpfung” (The essence of archi­ tectural creation) of 1894, called for architectural design “from with­­ in” out, which started out from the physiological and ­psychological premises of the viewer and thus made the effect of space on the ­subject its theme. Nor would the idea of space fail to become a theme in the practice of architecture. In lieu of classical gestures of prestige and ­image, architects began to concentrate much more on the “internal aspects” of architectural design and hence on questions of the ­relationships and connections between certain spatial structures and general behaviors. At the same time, values such as the atmosphere of a home or the mood of a space were addressed, which was the background for Adolf Loos’s effort to use architecture to explore the potential of new spatial forms with regard to perception. To that end, he worked with open spatial relationships and greater differentiation of the heights of spaces in order to evoke a stronger sense of space through the interplay of the incidence of light and detailed materialization. Instead of the familiar rows of closed spatial cells, which were passed through individually, Loos planned a walk 93

through a building as a sequence within a complex, interlocked ­spatial structure. This structure was evolved continually upward by means of differences in level and staggered floors. The vertical ­continuity of space—the Raumplan (“spatial plan”)—that he obtained by this means testifies to an innovation in the concept of space: the destruction of the boxy homes of the nineteenth century.

Theo van Doesburg, The Elementary ­Expressive Means of Architecture, drawing, before 1925.

The First World War had caused fundamental doubts about ­existing principles of perception and world order. Seemingly stable co­ ordinates had begun to totter, and hence the premises of design work began to change as well. The trend in painting, already evident ­before the war, toward radical abstraction or toward reduction of art to elementary design means would also lead to a paradigm shift in architecture. The Dutch De Stijl movement, which formed in 1917, was one group among others that no longer sought to ­distinguish itself though an exaggerated inwardness but rather, on the contrary, by a clear turn away from the individual and toward the universal. Its advocates wanted an art of scientific precision ­indebted entirely to the principles of truth, objectivity, order, and clarity. Its maxims lay in a rigorous denaturing of form, which not only took aim at a formalist, individual aesthetic but also sought to reorder the relationship between humanity and its environment or to society. In architecture—one of the focuses of the De Stijl ­discussions—this led to highly abstract rooms with decidedly compositional qualities. Buildings were no longer conceived as self­contained bodies but rather resulted from a variety of surfaces out of whose interaction the content of the space was formed. Dy­ namically decomposed from the inside out, they gave the impression of being an expanding, horizontal spatial continuum that interlocked with the exterior space. With this new, open architecture, which no longer tried to separate inside and outside, the traditional window was also a thing of the past. Instead it was declared to be an open plane that contrasted with the space-defining wall and ceiling panels as an element of equal value.

Gerrit Thomas Rietveld, Schröder House, Utrecht, 1924. View from south, upper ­story with living area.

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Hans Scharoun, Schminke House, Löbau, 1930–33. Winter garden.

Flowing Spaces: Visual Boundlessness and Clarifying Brightness From the modernist perspective, architecture was no longer a ­matter of designing form. Where until now conventions or even irra­ tional criteria had determined the choice of form, architectural ­expression was not supposed to be “mechanical”; from the “inside” out, in a sense, from the functional and constructional demands of the floor plan. Thanks to the constructional development of the skeleton frame, the unity of load-bearing and spatial termination in the exterior wall that had been applied to solid construction until now could be abolished. This resulted in great freedoms when organizing the floor plan. The once permanently outlined spatial cells gave way to a continual interlocking of different spatial zones, ­giving the impression of a flowing space. Progressive housing was equated with opening vis-à-vis the outside, and eliminating the separation of inside and outside became the declared objective of modern architecture. Any impression of gravity or the effect of mass was from now on considered an architectural taboo. The general trends toward dematerialization were intended as liberation from the nineteenth century and hence from the culture of the “overheated room” with its stuffed and cluttered ponderousness. Pre­ viously esteemed qualities such as decor or the production of a comfortable atmosphere were rejected as frivolities. They violated the principles of modernism, which was concerned with objectivity and authenticity. Freed of obligations to convey prestige, the floor plan offered an open, less formal structure that was supposed to animate its users to become active or to make such activity easier thanks to a functionalized organization of space. Openings and slits the full height or width of the room promised to integrate the environment authentically and reduced the share of the wall in favor of an optical removal of boundaries. At the same time, with the latent alternation of open and closed surfaces, ­movement was introduced to the viewers’ previously static perception of space. In contrast to traditional architecture, whose ­construction was laid out according to lines of sight and points of perspective, the spatial conception of modernism was based on a multiplicity of perspectives of observation. Movement played an essential role in this. The sometimes ambiguous constellations

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Ludwig Mies van der Rohe, Tugendhat House, Brno, 1928–30. View from the gar­ den, living area with large window facing the garden.

of space only became evident to viewers during the time they required to walk through them. As a consequence, the mise-en-scène of the path through the building or of the viewer’s constantly changing standpoint became a relevant theme for designing a space. Accordingly, light too became interesting less as a phenomenon of atmospheric effect than as a functional, goal-oriented quantity that served to make architectural structures visible. Usually it was regarded as a flow of light that could influence morality and ­energy: as a purifying brightness that was thought to kill germs. For modernism, light was thus by no means a passive illuminator but rather an active form, which flowed in and spread out almost unhindered in space, whose liveliness and forcefulness were ex­ pected to have an invigorating effect on the occupants. The Form of Windows and the Interior Hidden behind this increasing need for “display windows” was a transformation in ideas of housing that led in the early 1920s to a discussion among architects about the choice of the correct form of openings. This was for example the debate between Auguste ­Perret and Le Corbusier over the question whether a vertical or horizontal window format was preferable.10 Perret clung to the vertical format, while Le Corbusier saw the horizontal window as a suitable medium to give expression to new concepts of building and space.

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The point of departure for their polemics in the Paris Journal was the form of the openings of the Villa Le Lac (Petite Maison) in Corseaux, near Vevey, on Lake Geneva, which Le Corbusier built for his parents in 1923–24. Auguste Perret chose them to illustrate his critique of the “wrong” window forms Le Corbusier had been employing lately. Le Corbusier was said to be creating “tortured window forms by making the windows too long or too wide,” which from the outside certainly seemed very original but altered unfavorably the interior, including its relationship to the outside world, and above all led to poor natural light. Rather, he claimed that a window should be upright, by anthropomorphic analogy to human beings, and thus establish a supporting frame. Whereas the horizontal window “condemned one to regard an eternal panorama,” the traditional vertical window stimulated our senses “by enabling us to see a complete space: streets, garden, sky.”

Huis van Brienen, Herengracht, Amsterdam, 1728. Vertical window onto Herengracht. Le Corbusier and Pierre Jeanneret, Villa Le Lac (Petite Maison), Corseaux, near ­Vevey, 1923–24. Ribbon window with view of Lake Geneva.

Le Corbusier defended his horizontal windows (fenêtre en l­ ongueur) in all respects against these arguments. First, he emphat­ ically rejected the accusation that horizontal windows provided too little light, as he was concerned precisely with bringing “as much light as possible” into the interior. Le Corbusier countered Perret’s insistence that a window be vertical analogously to a human being by justifying the horizontal window as reference to the hor­ izontal orientation of the sense of vision. Furthermore, he claimed the horizontal window was the adequate expression for the new ­con­struction methods such as reinforced concrete which made grea­t­ er spans and hence wider openings possible. The horizontal ­window was also said to be well suited to the modernist ambition to connect inside and outside as closely as possible. The horizontal window depicts the landscape as it is, objectively, clearly, and undistorted: “The 11-meter-long window introduces the immensity of the outdoors, the unfalsifiable unity of a lakeside landscape with its storms or radiant calms.”11 97

In his analysis of the debate, Bruno Reichlin tried to sum up the qualities and special features that argue for one or the other type of window. With regard to its reproductive quality, he says of the classical vertical window: “Because the vertical window allows the eye to wander downwards to the first and closest spatial places—street and garden—and horizontally to the middle and further planes—houses opposite, trees, hills in the background—and upwards into the limitless reaches of the sky, it displays a detail of maximum perspectival depth, an abundance of variety and nuance in respect to the dimensions, colorfulness, and brightness of the landscape.”12 Thus it offers more information about the outside world and a stimulating visual variety. By contrast, Reichlin writes of the horizontal window that it diminishes “our perception and correct appreciation of the depth of the landscape” by reducing the view to one central level with only a little spatial depth. Moreover, this is said to be reinforced by the great distance between the vertical terminations of the window which practically disappear from the natural field of vision. The consequence is an immediate presence of the surroundings that seems “stuck” to the window pane. To put it another way, while classical vertical windows produce a self-contained interior in which human beings retain control over the scene grasped as a whole, the horizontal window undermines the accustomed pro­tective shell or, as Walter Benjamin called it, the “case” of the private person. In this case, the outside world controls the interior by domina­ting it with its omnipresence. As far as the lighting characteristics of the horizontal window are concerned, Perret’s critique that it provides “no light” is objectively neither correct nor incorrect. Rather, both formats of window can result in fundamentally different lighting conditions. The ­traditional vertical window does indeed ensure that daylight penetrates well into the interior. The alternation of windows and walls and the traditional subdivision into main versus front window, top versus bottom window, mullion and transom versus casement, windowsill, and lintel also lead to a varied play with areas of ­differing brightness and darkness. Light and shadow alternate in subtle nuances, guiding the gaze from objects veiled in darkness and only vaguely recognizable by way of discreetly lit places to ­unremittingly bright areas. Next to the relative wealth of contrast of this form of lighting that bolsters sensory and plastic perception of the interior, the horizontal window envelops primarily the areas near the window and parallel to the facade with a uniform light with little modulation. Depending on the intensity of the natural light entering, it can vary between harsh and diffuse. Consequently, ­especially near the window, the objects and zones of the space are lit evenly, which can give them an objective character. 98

Lois Welzenbacher, Heyrovsky House, ­Thumersbach near Zell am See, 1931–32. Living room with view over the terrace ­toward Zell am See.

The Mise-en-Scène of Prospects The increasing reduction of the closed wall served not only to help the experience of light and open up the surroundings; ambitious projects for apartment buildings soon sought to influence how the occupants lived. Unlike buildings with large window surfaces— such as the Bauhaus in Dessau or the Van Nelle factory in Rotterdam—it was not about deliberately breaking through the shell in a very specific place to produce an active viewing of the surround­ ings. Rather, a specific visual experience was intended to which the furnishings of the space were sometimes subordinated. The occu­ pants were to orient themselves directly at the image offered through a large panorama window with no muntins—television avant la lettre. In some cases, the entire building was oriented toward such a prospect and designed accordingly. The Austrian architect Lois Welzenbacher achieved an all but unsurpassable mastery of this in his residential buildings in Alpine regions. He wrote: “It was ­important to ensure that easily movable openings and clever combinations of space be used to create views out and through that ­communicate a feeling of immediate connection with the great space of nature. I open the building to the east, the south, the west in ­order to create an omnipresence of the extravagantly beautiful landscape. ... As one walks through the rooms, the landscape is offered up in constantly changing details.”13 Variety of experience, constantly changing views and prospects of the architecture and the surroundings where the cornerstones of Le Corbusier’s conception of architecture. He saw the house as a sphere of experience in which dynamic perception—the famous promenade architecturale—sought to capture particular views and prospects. Windows were the means to achieve this, like the lens of a camera, capturing different motifs and sensory impressions and thereby shaping the building into a true machine for seeing. The ­interior had long since ceased to be opposed to the outside world; rather, that world was inscribed and integrated into the living space: architecture domesticated its immediate surroundings.

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Architecture domesticating its ­environment: Le Corbusier and Pierre Jeanneret, Villa Le Lac (Petite Maison), Corseaux near ­Vevey, 1923–24. View of Lake Geneva from garden. Le Corbusier and Pierre Jeanneret, Villa ­Savoye, Poissy, 1928–31. Terrace.

Richard Neutra, Wise House, San Pedro, CA, 1957. Living room with view of the Pacific (following double-page).

Last Stop: Glass House Whereas the destruction of the Second World War in many parts of Europe necessitated pragmatic architecture for rebuilding, modernist visions flourished across the Atlantic. That was pri­ marily due to such personalities as Walter Gropius, Marcel Breuer, and Ludwig Mies van der Rohe—that is, the elite of European ­architecture who met up in the United States, after several detours, and brought with them their ideas and concepts for a modern ­architecture. At the latest from the time of the landmark exhibition The International Style at the Museum of Modern Art in New York, organized by Henry-Russell Hitchcock and Philip Johnson, modern architecture had become socially acceptable. Moreover, ­architects from Europe such as Richard Neutra and Rudolph M. Schindler had already successfully made the American public more open to the ideas of European modernism. Beginning in the 1940s, the West Coast of the United States became an ­Eldorado for the flat-roof glass homes that we know from the beauti­fully staged photographs of Julius Shulman. It is not surprising that the emancipation of the window should reach another culmination in the United States. Even the idea of a window as a holelike opening in the facade seems irrelevant if we think of the two houses that reflect the quintessence, so to speak, of the modernist will to build and have long since become insignia of twentieth-century architecture: the Farnsworth House in Plano, IL (1946–51), by Ludwig Mies van der Rohe and the Glass House in New Canaan, CT (1949), built for his own use by Philip Johnson, a friend and comrade-in-arms of Mies. There are neither walls nor holes, ribbon, panorama, or any other kind of windows, just one great shell of glass. Much like Mies’s ­Tugendhat House in Brno (1928–30) before them, these two buildings were discussed and criticized at length. Their influence on later residential architecture would be significant, both on architects who consciously took up the idea of the “glass house” and on those who took a critical position.14

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Richard O. Spencer, Spencer House, ­Malibu, CA, 1955.

If the Expressionist dreams had become true, these glass buildings of the postwar period could finally have been their realization. In fact, however, the “paradise on earth” whose praises Paul Scheerbart sung at the beginning of the century, with its complete transparency and programmatically dramatized fusion of interior and exterior, exhibited unmistakable weaknesses. In addition to the fundamental insecurity of the occupants—are they inside are outside?—there is a visual uncertainty in which the supposedly total visual experience becomes a constant fun house of reflections. This can sometimes be inspiring but also vexing, especially when movements in the exterior join in with the reflections. Even Philip Johnson had to admit in retrospect in 1983: “I can’t work in a glasshouse. There are too many squirrels running around.”15 104

In an essay on Dan Graham’s works, Jeff Wall underscored the deceptive transparency of glass in terms of invisibility.16 He ­described very subtly how the relationship of Philip Johnson’s Glass House to its environment changed by day and at night as well as the associated interplay of transparency, reflections, and lighting effects. During the day, the reflections on the glass wall can mirror the surrounding landscape and shield the interior from gazes from outside. The view from inside into the surroundings is more or less preserved, depending on the lighting conditions, but when artificial light in the interior comes into play, its reflections on the glass skin increase. The heightened reflection of the inside of the glass surfaces can thus move the reflection of the interior and the occupants into the landscape. Thus the intended gaze from inside out loses on the whole its controlled directedness; it is subject to the dynamic of uncertainty based on weather conditions.

Philip Johnson, Glass House, New Canaan, CT, 1949. Johnson at his working desk, view, interior.—Johnson’s laconic commen­ tary on the reflections in the glass: ­ “I can’t work in a glass house. There are too many squirrels running around.”

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Philip Johnson, Glass House, New Canaan, CT, 1949. View by day, with reflections of the environment, and one at night.

The atmosphere of the space in the building undergoes a surprising change at night, when the optical relationships between the living space and nature are cut off: “At night, when nature withdraws, leaving only blackness and absence behind, it becomes an eye in its invisibility and emptiness. ... It is this combination of slight shocks (the disappearance of the natural spectacle, the mirrorization of the interior, and the resulting reversal of asymmetry) which gives rise to a return of anxiety in the familiar form of fear of the dark.”17 The mechanism of the glass house turns into its opposite: “Nocturnally, the lonely pavilion becomes the abandoned crypt of Gothic tales, and the theoretical invisibility of the occupant, his aversion to reflections, indicates an affinity with the vampire.”18 So what is left as a final resort for those who are afraid and can only trust to a limited extent the security of the glass boundary? Pulling the curtain: there “the transparency of modernism” runs up against “its profane limitations.”19 Rehabilitating Darkness One negative component of postwar architecture was a kind of functionalism for the construction industry carried out in the name of internationalism, which in many cases led to a trivialization of High Modernism. The curtain walls that appeared everywhere in commercial functional architecture, with their tendency to in­ sipidness and shadowless overexposure, increasingly set the tone for cityscapes. Correspondingly, in Das Prinzip Hoffnung (The ­principle of hope) of 1959, Ernst Bloch harshly judged the function­ alist, one-dimensional architecture of abstract grids and volumes stripped of meaning: He characterized such architecture as “kitsch of light” as well as “ready to leave”—as if it expressed departure. “Bright and bare like sick-rooms” on the inside, the exteriors of the buildings seemed “boxes on movable rods.” He described the ­liberation of architecture from the musty smell and ornamentation of the nineteenth century as, on the whole, a dubious form of

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­ rogress and asserted it was “no longer disguisedly but deliberately p soulless.” In return, discomfort with the lack of expressiveness of glass architecture organized by purely rational and objective perspectives resulted in a desire to revoke the excess transparency. Modernism had—primarily for ideological reasons—employed glass as its primary construction material to create ideal shells for ­imagined ideal people. It was precisely this attitude that should be stopped now in order to tackle not only the loss of everyday utility but also the sensory deficits for which glass architecture was blamed. Formal expression and the viewer’s affective experience of space would again become important themes in architecture. Louis I. Kahn, for example, was an architect who stood precisely on this dividing line between the postulates of modernism and the postulate that would define the postmodernism that followed it. Thus Kahn, on the one hand, with his faith in the power of his ­vocabulary of geometric forms, used grid structures and stabilizing axes. On the other hand, however, his unadorned, interpenetrating volumes and his open conceptions of space are very much in the

Louis I. Kahn, Margaret Esherick House, Chestnut Hill, PA, 1959–61. Entrance. Louis I. Kahn, Norman Fisher House, ­Hatboro, PA, 1960–67. View from the ­kitchen toward the dining area.

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spirit of a modern feeling for space. The perforated box from which modernism had departed was rehabilitated by Kahn: he ­surrounded the flowing space with barriers again in order to transfer it into a stabilizing equilibrium. The revocation of excess ­transparency also led to a return of the window as hole. This hole was of course larger and of a more refined outline than its pre­ decessors and mediated between the hunger for light and the need for security. The large and smooth surfaces of his monolithic ­building volumes gave lots of space for the changing natural light situations. Ribbon windows and slits allow sufficient daylight to infiltrate the housing. Moving beyond modernist functionality, it no longer served simply to light or illuminate the rooms but also as an aesthetic element that could change the form of the architecture. The light was there to heighten the perception of the spatial and tectonic order. Moreover, the wandering traces of the sun, the cast shadows, and graduated contrasts of light and dark made it possible to experience time in the room and provided occupants with a wide variety of moods from morning to evening. From the Form to the Shell Since the 1960s, the increasing break with modern design principles could no longer be dismissed. Postmodernism served up an enormous wealth of forms and a visual architectural idiom. This paradigm shift was primarily caused by the society’s general trends to popularization and individualization. For example, Pop Art had earlier provided a crucial turn in art when it bid farewell to abstract, nonobjective painting. It incorporated motifs from everyday life, the consumer world, and advertising. In architecture, this interest in immediate communicability led to the ­rediscovery of historical and anonymously constructed buildings which were said to have more communicative power than mod­ ernist buildings. The background for such reflections was in no small measure a changed relationship to the user. Whereas modernist architecture had a certain inherent social morality, which, based on the principle that “all humans are equal,” placed the ­accent on repetition and similarity, postmodernism left this self-image of the avant-garde behind. In place of the authoritarian act came planning oriented toward the diversified needs of the occupants. Hence postmodernism’s efforts to break free of the modernist ­tradition ran in a wide variety of directions; every means was justified, as long as it promised stylistic change. After three decades during which the discussion of architecture concentrated mainly on problems of form, there was a new shift in accent in the 1990s, from form to surface. Today architecture increasingly seems to be a refined, neutralizing shell that seeks to adapt as flexibly as possible to the changing demands of use. If modernism may be said to have focused solely on the architectural object and its functional structuring, in times of deprogrammed spatial formulation design is finding new inroads to urban planning. The position of the architectural volume and its cultural anchoring in its particular context are the two most important determinants for designing facades today. In addition, technologically indicated fusions between the load-bearing system and the surface and the postmodern discovery of the inherent aesthetic value of ­materials have led to a change in the status of building materials.

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Buchner Bründler Architekten, Loft house, Colmarerstrasse, Basel, 2000–2002. ­Facade facing street.

New Pleasure in Transparency: “The Un-Private House” In the context of the heightened sensitivity for the building shell and the materials, a new pleasure in transparency in architecture has been aroused. The devastating mistakes of functionalism and an awareness of the ecological implications that set in after the oil crisis put a stop, presumably only temporarily, to the extensive use of glass. Yet the desire for more light that had been ­awakened in the twentieth century continues undiminished, especially in central and northern Europe. With great progress in ­material technologies, especially where glass is concerned, transpar­ ency has been experiencing a new boom since the end of the last century, this time apparently with an even more overpowering force than in the modernist era. The reasons for this are not, ­however, solely technical or aesthetic in nature but should also be seen as a sign of the changed relationship of human beings and their environment. Visibility and openness, often evoked maxims of modernism, have become a matter of course today. The view of

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the intimate, private, and hidden that was forbidden not all that long ago has become a trivial, fatiguing everyday phenomenon. Trans­­­ parency, once a morally and ideologically charged slogan, now seems to be reduced more than ever to a specific quality of materials, to a “game in which something that no longer surprises is shown off.”20 The increase in the private (or privatized) and the constantly progressing decay of all clearly defined areas of public life— which was already discussed by Richard Sennett in the 1970s21—have ­ultimately become significant factors in the design solution of the transition from interior to exterior. What once marked a clear ­dividing line has become a permeable membrane. Against the backdrop of such an observation, the tendency of a new generation of city dwellers to make private life public in a glass-enclosed space seems like an allure motivated by narcissism and may at most confuse us with its unorthodox application of glass as a building material: “These plans and the built houses gain their effect of radical modernity from the novel effects the ­in­gression of vast expanses of glass has on the notion of privacy.”22 The occupants of glass dwellings who declare themselves de­cidedly urban and progressive by condemning the veiling of private life as bourgeois and philistine and instead living in “un-private houses”23 are in fact following to its logical conclusion the bourgeois, conventional paradigms of housing. Status and self-promotion of a certain lifestyle and taste are central factors, and the glass wall becomes a medium to convey this to the outside. What we have long since known from other areas of architecture has reached the domestic sphere: the windows as such have disappeared and become assimilated by a glass facade. The facade in turn has become a screen, a media carrier that reflects, depending on the position of the viewer, the lifestyle of the occupants or the urban landscape of the gentrified trendy neighborhood. Semitransparent Shells: Veiled Views and the Diffusion of Light Yet this complete visibility too seems to be in retreat again. For ­example, in an age when, instead of a true view through, more and more intermediate states between exhibition and disguise are called for, the semitransparent facade is a new option. Whereas in the wake of the authenticity of materials advocated by modernism, and when the visual objectivity sought to create glass skins as thin as possible and to expose the constructional system, today projects are often distinguished by complex cuts in the facade with a number of materials and in-between spaces. New technological advances with materials make it possible to have glass skins that can fulfill all of the protective functions of isolation, insulation, climate and sun protection all the way to energy production. Moreover, the semi­ transparent shell provides an opportunity to draw a line between inside and outside and thus provided the users whom postmodernism had granted autonomy with the everyday utility that the ­transparency of modernity had left them without. What they sought was by no means the complete separation or encapsulation of the nineteenth century but merely a screened-off area that permitted individuals to withdraw partially from the world of economic growth and its excess of stimuli. Unlike the large panorama windows of modernism, today’s membranes, screens, filters, and seethrough grilles provide a certain distance between observer and ob-

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ject. Whereas translucent materials resist the visual onslaught from outside, they enable the occupants in the interior to get away from the spatial continuum for a time. Similarly, grilles and veils break down the outside world into changing excerpts or in the extreme case reduce it to an amorphous schema. In the process they not only blur sharp focus but also function as a soft-focus lens for the light.

SANAA (Kazuyo Sejima & Ryue Nishizawa), M House, Tokyo, 1996–97. Courtyard. Henke & Schreieck, ÖBV residential ­building, Vienna-Hernals, 1990–93. Loggia of a maisonette apartment. Baumschlager & Eberle, Housing complex, Sebastianstrasse, Dornbirn, Vorarlberg, 1999–2001. Skin facade with silk-screen, sliding plates of glass.

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The use of semitransparent glass materials, translucent plastic lining, or any of an infinite number of perforated materials produces spaces that are quite distinct from the shadowless light of modern spaces. Their predecessors may be found, for example, in the opales­ cent screen walls of traditional Japanese homes, in the illusionistic filtering and veiling effects of Art Nouveau, and in the work of Frank Lloyd Wright and Pierre Chareau, who unlike their colleagues placed importance on clouding light by using colored glass and glass brick. Natural light is no longer credited with a “pur­i­ fying” effect and the ability to create clarity, but neither should it be limited to aesthetic attractions. Instead, there is much more ­effort today to create an atmosphere in which direct spot lighting and especially light entering the room indirectly become part of the sensory experience of space. The tools for such lighting drama­­ turgy are varied. Opaque, translucent walls make the light seem muted. They immerse the interior in a cloudy translucence and lend it a pale, dreamy glow. At the same time they seem to result in ­diffusion of the material and thus ensure there are soft forms and delicate materials that appeal to an intuitive sensory perception. By contrast, shades, slabs, or venetian blinds, which refract the light and create shadows and small scales, produce effects that stimulate the subjective imagination, ranging widely from enigmatic nuances to narrative light-and-shadow images. Metamorphoses of the Facade Since the 1990s, progress in material technology and a transformed understanding of transparency in architecture have provided new impetus. Minimalism and the associated challenge to return to a new simplicity seem to many architects to be an adequate response to the confusing diversity of styles and forms of the recent past. A new love of materials is being celebrated, and not infrequently it is accompanied by an extravagant use of glass. This trend to reduced boxes with full-height windows—what Kenneth ­Frampton has called “degree zero architecture”—has seized the main­ stream as well in recent years, even public housing, though with the latter often in a way that testifies to fading design energy and an impoverished repertoire of forms. Leaving aside the aesthetic ­deficiencies and the question of social acceptance, these glass boxes also produce constructional difficulties despite the many tech­ nological advances in materials. For example, an entire arsenal of defensive measures is necessary to effectively protect the blank glass shell against numerous environmental effects and weathering. These include such profane requirements as protection against sun, glare, prying eyes, and burglary. Some of these challenges can be met using measures in the interior, such as venetian blinds, ­curtains, or drapes of every kind, but the problem of regulating direct sunlight—one of the most important requirements for a ­comfortable climate—remains even with energy-efficient glass. The goals and methods of regulating the climate in buildings have been redefined by current issues concerning the resources and en­ vironment, now concentrating on reducing the need for finite ­energy sources. Unlike in the old days, when the design of the facade was determined much more by the reassuring certainty about the technological possibilities, today there is an urgent need to design the shell with the exterior climate in mind. For some time

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now, it has been increasingly popular to employ once again secondary control elements in the facade that are independent of the ­architecture as a way of reducing the solar radiation of the outermost surface and hence considerably reduce the challenges for building services. Where Le Corbusier’s brise-soleil as a self-standing element heralded a process in which the outer shell of the modern building would gradually become more complex again, today the pragmatic applications of protection against sunlight also offer us the possibility to develop once again an original architectural idiom beyond all the stylistic isms and arbitrary forms. Reveiling the Unveiled: Protection from Sun and Prying Eyes Where once the building volumes were torn open and articulated in keeping with the maxims of the Modern Movement calling for “light, air, sun,” and spaces had been opened up to natural light and to the surroundings with numerous or large windows, one char­ acteristic of the facade grew in importance. It was produced by the window itself, but could not be overcome by the window alone. When it became necessary to adjust the window to variations in the amount of solar radiation, to the natural rhythm of day and night, and to individual needs for security and seclusion, modernist architects were confronted with a dilemma: they had just freed the building volume of ornament and decoration, and now they found themselves compelled to disfigure it with fittings to protect against sun and glare. Flora Steiger-Crawford wrote in retrospect: “Rudi [= Rudolf Steiger] knew from the Zett House how difficult it was to install sun shading on large windows extending to the ­ceiling without disturbing the aesthetic of the building.”24 This ­circumstance would, however, develop into an extremely fruitful stimulus to dealing in highly diverse ways with the themes of sun and glare protection. It is revealing that soon it was no longer a

Marcel Breuer, Grieco House, Andover, MA, 1954–55. Facade with projecting slat lattice.

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matter of finding optimal sun and glare protection but that this ­factor increasingly became an aesthetic end in itself. Certain architec­ tural solutions became—very much in the spirit of a new orna­ mentation—principal expressive elements of the facade and thus part of a specific aesthetic attitude. It speaks for itself when Aladar ­Olgyay and Victor Olgyay, in their important publication on solar control and shade took as their programmatic motto a statement by Marcel Breuer: “The sun control device has to be on the outside of the building, an element of the facade, an element of architecture. And because this device is so important a part of our open archi­ tecture, it may develop into as characteristic a form as the Doric column.”25

Pierre Koenig, Case Study House No. 22 (Stahl House), Los Angeles, CA, 1959–60.

Traditional forms of sun shading such as two-sided shutters or ­vertical sliding shutters were out of the question on modern ­buildings above all because they were “not modern.” They were of little practical use anyway on larger windows and the newly ­fashionable ribbon windows. With the exception of those architects who simply ignored sun and glare protection and relied on solutions inside the building, architects either used flexible constructions like roller shutters or venetian blinds or a fixed integration of the solar protection into the architecture. These fixed constructions included canopies, horizontal and vertical blinds, brises-soleil, ­loggias, and balconies, but mounted slats soon became crucial elements in facade design. Frank Lloyd Wright was an early master of wide roof projections to protect against the sun, beginning with the Prairie Houses he designed between 1893 and 1920. For the Martin House in ­Buffalo, NY (1904), the Robie House in Chicago, IL (1908), and the Gale House in Oak Park, IL (1909), he organically combined solar protection and an architectural program into a coherent expression. While the broadly projecting, shallow-sloping roofs on his low ­proportioned buildings were intended to reflect the horizontal landscape that surrounded them, they also produced appealing exter­ior areas that were protected against the sun. A few decades later, the architects who designed the many elegant homes in the United States, especially on the West Coast, found fruitful inspiration in Wright’s architecture. In addition to their generous use of glass they employed various kinds of projecting roof constructions as a characteristic design element. Sun protection and the will to ­architectural expression were once again closely related. Probably the most famous form of fixed sun shading, how­ever, mutated in the twentieth century to mounted slats and ­­ brises-soleil (“sun breakers”), which Le Corbusier claimed to have invented. Already in the early 1930s he had experimented with ­external sun shading in projects in hot climates (Villa in Carthage, apartment building in Barcelona, projects in Algiers). Finally, ­brises-soleil obtained perhaps their most impressive form in the Unité d’habitation in Marseilles (1945–52). A grid structure runs across the east, west, and south facades of this north–south ­oriented housing complex. The alternation of recessed areas, hor­ izontal strips formed by the balcony walls, and brises-soleil ­essentially sets the tone for the facade’s sculptural appearance and relates to the roof landscape with its biomorphous concrete ­sculptures. The brise-soleil may at first glance, thanks not least to 114

Le Corbusier, Unité d’habitation, Marseilles, 1945–52. Sculptural accents on the facade by means of vertical and horizontal brises-soleil, brises-soleil on the service area floor and in the loggia of a housing unity.

its almost archaic simplicity, win us over as a perfect solution: “The brise-soleil is one of his [= Le Corbusier’s] most masterly in­ ventions, one of the few last structural innovations in the field ­ of en­vironmental management that we have seen,” Reyner Banham wrote in 1969. 26 This is probably true in the specific case when the building has the optimal orientation relative to the sun’s path. In the case of the Unité, however, the brises-soleil are installed in the same way facing the east, south, and west, which by no means takes into account the actual relationship to the sun. Only the ­apartments on the narrow southern side—which from April to September receive generous shade and in winter receive as many as eight hours of sunlight—can profit from the functionality of the brises-soleil. The efforts to achieve optimal sun shading were ­obviously displaced by aesthetic considerations: Le Corbusier prob­ ably had the overall plastic-sculptural impression of his béton brut building more in mind than a subtle approach to different qualities of natural light. In general, the example of the Unité illustrates the limits of a rigidly mounted sun shading because it can­not be adapted to changes in the course of the sun over a day and with the seasons. 117

The real playground in matters of sun shading in twentieth-­­ century architecture was flexible constructions on the facade. The diversity of types—the spectrum ranged from roller shutters and slat blinds by way of awnings, hinged, folding, and sliding shutters to more elaborate versions (for example, insulated glass with integrated slat blinds)—offered many different design possibilities. Despite initial reservations, roller shutters and awnings grew in popularity even during the era of the Modern Movement—not least thanks to their relatively discreet and slender construction, which could also be applied to the facade after construction. Here too successful integration of these elements into the architectural program could lend the buildings a certain expression: who would not associate the usually blue-and-white-striped sun ­awnings with liberating visits outside one’s own four walls in some sun-drenched place or on a Mediterranean beach promenade?

Design for an advertisement for better ­letting of six-room single-family homes in the Neubühl Werkbund housing develop­ ment, Zurich-Wollishofen (1928–32). Brinkman & van der Vlugt, ­Sonneveld House, Rotterdam, 1929–33.

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Riegler & Riewe, Residential building, Graz-Strassgang, 1992–94. Facade with sliding shutters.

Today the old hinged, folding, and sliding shutters are in ­fashion again for residential buildings, because they lend a kinetic, playful dynamic to the design of sun shading. The ultimate ­renaissance of the sliding shutter is probably the much admired residential building in Graz-Strassgang (1992–94) by Riegler & Riewe. It employed horizontal sliding shutters in front of French windows on the east and west facade, and they essentially de­ termine the appearance of the building’s exterior. Inside, all three spatial layers are connected by numerous openings (sliding or ­folding doors) and offer diverse possibilities for use, which is also transported outward by means of the characteristic sliding shutters: the shutters facing east are made from expanded metal while those facing west are covered with nylon fabric. They make it ­possible to adjust individually the amount of natural light entering as well as the views in and out. Modulated and dispensed by the position of the sliding shutters, daylight plays a crucial role. Herzog & de Meuron’s concept for the folding shutter con­ struction for their residential and commercial building on Schützen­ mattstrasse in Basel (1992–93) is a touch more playful than Riegler & Riewe’s. The building is constructed on a narrow and deep lot, and its apartments are grouped around an inner courtyard that opens onto the neighboring property to the south; its facade facing the street is completely glass. In front of this glass facade is a curtain wall of cast iron; the pattern of its folding shutters recalls drain covers. They can be folded open individually, and they cause the appearance of the building to change constantly. The 119

Herzog & de Meuron, Residential and commercial building, Schützenmattstrasse, Basel, 1991–93. View from street. Henke & Schreieck, ÖBV residential ­building, Vienna-Hernals, 1990–93. Facade with sliding shutters.

i­ nterplay of open and closed shutters leads to a charming modulation of the facade, whereby the wavelike slits of light across the floors describe ever new vertical lines of connection. With the blinds closed in the sunlight, by contrast, the building seems closed off and conveys an introverted character. It offers an almost magical image at night, when light from the apartments passes through a textile window covering. By means of this dynamic and almost artistic use of sun shading elements, the architects ­produce a variety of aggregate states of a building and thus contribute fundamentally to the liveliness of the immediate urban sur­ roundings. 120

Horizontal sliding screens also set the tone for the apartment building on Frauenfelderstrasse in the Hernals district of Vienna (1993) by Henke & Schreieck. As in Graz-Strassgang, the individually adjustable shutters in front of the maisonette ­apartments on the south wing of the site offer more than just protection from the sun. They stand for a program that counters the crampedness and rigidity of standardized solutions with a maximum of openings and flexibility. The open structure it offers can be regulated by the occupants as they desire—even in the generous transition area between inside and outside. Loggias combine with the venetian blinds and the sliding screens to offer several layers of filters between the public and the private. Individually modulated and meted out according to the atmosphere ­desired, natural light becomes a decisive factor. Particular attention is paid to the incidence of light in the courtyard as well: the ­maisonette apartments are connected by means of glass-roof exterior arcades that are staggered back toward the top in order to let in more light and air. It is precisely the spatial transformability and openness that are reflected in the solutions for the details; ­combined with a well thought-out architecture that establishes many connections to the existing architecture of the surroundings, it ensures the quality of this residential building. Multiple Layers Another possibility to block out light and views in lies in creating a second layer of the facade—much like balconies or other projections from the facade—which can also serve as natural sun shading. Just how little is required to make it possible to experience multiple layers is demonstrated by Egon Eiermann’s own residence in Baden-Baden (1962). The large glass surfaces are in this case

Egon Eiermann, Eiermann House, BadenBaden, 1962. Balcony with movable sails for protection from the sun.

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Baumschlager & Eberle, ­Mitterweg ­housing complex, Innsbruck, 1996–97. ­E xterior skin of oak slats.

Baumschlager & Eberle, Wohnen am ­Lohbach housing complex, Innsbruck, 1997–2000. Skin of building with copper folding shutters.

just one part of the layered facade construction. A delicate steel structure attached to the white awning defines a transitional area whose floor is constructed of balcony slabs with flowerpots set into circular openings. Venetian blinds and simple canvas curtains supplement the awning and permit a subtle approach to light and shade. Using the simplest means, Eiermann produced a second level of the facade that can be experienced spatially and created a highly differentiated, individually adaptable transition ­between inside and outside. The regulation of various intensities of daylight is a decisive contribution to this. Surely the most striking feature of the Mitterweg housing ­complex in Innsbruck (1996–97) by Baumschlager & Eberle is the refined external skin of oak slats. It surrounds, regularly perforated by openings, the housing blocks at a distance equal to the balconies. The openings are staggered, creating a kind of geo­ metrical pattern that lends the buildings a functional, urbane note but at the same time respects the local tradition by using wood as a building material. Moreover, the oak grating forms a continuous exterior area that is narrow on the north and south sides and thus extends the outline of the rectangular building volume into a square. While the narrower balcony areas can be used as a corridor or storage area, the ones on the west and east sides form an appropriate private outdoor space. As a semitransparent membrane that should certainly be understood as a pointed contribution to the theme of transparency, the oak grating marks the transition between exterior and the surroundings. Views out, through, and in change constantly according to one’s standpoint. Finally, the delicate oak slats can also serve as filters for the natural light that enters, which can penetrate through the vertical windows deep into the living space. Simple means achieve here exciting, varied multiple layers that make an essential contribution to the high quality of life on Mitterweg. It is a quality that it shares with the ­Wohnen am Lohbach housing complex (Hötting-West, Innsbruck, 1995–96) by the same architects. There instead of the wooden ­grating they used horizontal hinged shutters of copper that run continuously around the balcony zone and make it possible to close up the facade completely. The emphasis is on the occupants’ playing individually with this external skin of the building.

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MVRDV, Apartment building, AmsterdamBorneo Sporenburg, Borneo eiland, 1999–2000.

Shown in a Good Light The large window is an essential feature in various recent designs. The amount of wall is sometimes reduced to a minimum, since ­abstraction and formal reduction have in many circles become the epitome of modern, progressive lifestyle. This attitude has actually led to a loss in the window’s importance as a traditional ­element for designing and articulating the space. The consequences of this reduction to a simple glass plane are even, unexciting light levels and an undermining of the natural sense of privacy. ­Cor­respondingly it seems worthwhile to recall what a residential ­building really is: primarily a territory and shell for the private sphere of its occupants. Its task is not only to house but also to regulate and protect against the surrounding outside world. ­Otherwise, precisely in times like ours, when the surroundings are characterized by high building density and a general visual ­overload, this early critique of modernism’s excessive use of glass is all the more valid: “Anyone who has had an opportunity to live for an extended period in a building turned completely inside out will have experienced first-hand the consequences of such ­­ one-sidedness and exaggeration. They will realize that a constant dialogue with the outside world, a splendid and exacting but ­unchanging Alpine or lake panorama, will get on their nerves under certain weather conditions and in certain moods.”27 Today it is all the more necessary to reflect once again on the qualities that make for a good facade—above all determining a useful size of the openings, which precisely when it comes to a residential building means more than good views (outward) but also balanced lighting. A uniform and hence undifferentiated ­handling of the interplay of light and sight can have unfortunate consequences. In this context, we should recall Hermann Czech’s remark that “our ordinary window in the wall ... is more an example of unmastered natural light, since it causes the brightest and darkest places in a room to collide. The brightness all but forces us to look out, which sometimes can almost seem ­ a burden. 28 Czech points out that Bruno Taut had already discussed this dilemma in 1921 when he called for “windows of uniform ­design but distinguished by their placement into windows for lighting the room and others for looking out.” Or likewise when Walter Gropius proposed in 1927 to “separate lighting, ventilation, and views.” Although the proposals of Taut and Gropius were the views of proven modernists, even today they could inspire us to a more considered employment of windows suited to the circumstances. General recipes for success independent of local conditions and individual needs for use will not be very practical, and all too often built architecture seems to employ large windows as a way to get around an intelligent solution to the interplay of light and sight. A look back at architectural concepts of the past has not only demonstrated the changing role of light phenomena but should also be an occasion to assert decidedly more freedom for lighting in the future. Particularly in residential architecture, where there is no need for uniform lighting situations, one can take the risk of too much or too little light. Different quantities of light and ­variation in the types of opening for a focused, unlimited, or veiled view can provide latitude for innovation.

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Moreover, it is to be hoped that architects once again turn i­ ncreasingly to the design potential of glass. This building material is frequently still, very much in the modernist manner, reduced to the phenomenon of transparency and consequently employed to eliminate spatial boundaries. Only a few contemporary examples of extensive use of glass demonstrate the necessary sensitivity to play with the qualities of the material; glass-specific effects such as distortion, vexation, reflection, or coloring. Other buildings, in turn, start out from a sensible and balanced or even surprising combination of glass with other materials or mix different types and qualities of glass. Thus they can produce exiting, well-lit rooms that are not determined only by glass’s invisible qualities but also its visible ones. For a long time architects had trouble coping both with modernism’s verdicts against ornament and with its postulation and glorification of constructional honesty, but after decades of forced asceticism they are now trying to redefine decoration. Thus the constructions applied to facades for protection from sun and gazes have long since proven to be an essential component of architectural expression. Whether they are fixed parts or movable controlling elements, they all seem to have an inspiring effect on architectural activity today, and thus they allow natural light to be not just one source of light but rather grant it a central role in the design of facades.

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1 Adolf Krischanitz, “Loch und Wand,” in Günther Uhlig, Niklaus Kohler, and Lothar Schneider, eds., Fenster: Architektur und Technologie im Dialog (Brunswick: Vieweg, 1994), 75. 2 Kyra Stromberg, “The Window in the Picture—The Picture in the Window,” Daidalos, no. 13 (1984): 54–63, here 54. 3 Günther Uhlig and Jan A. Wolff, “Vier Spots aus der Kulturgeschichte von ­Fens­ter und Tür,” in Uhlig, Kohler, and Schneider, Fenster (note 1), 20–33, here 20. 4 Ibid. 5 On this, see Beatriz Colomina, Privacy and Publicity: Modern Architecture as Mass Media (Cambridge, MA: MIT Press, 1994), here 233ff. and 283ff. 6 Le Corbusier, Urbanisme (Paris: Crès, 1925), 174: “Loos m’affirmait un jour: ‘Un homme cultivé ne regarde pas par la fenêtre; sa fenêtre est en verre dépoli; elle n’est là que pour donner de la lumière, non pour laisser passer le regard.’” Frederick Etchells’s translation of this passage—Le Corbusier, The City of To-morrow and Its Planning (London: J. Rodker, 1929, 185–86)—is inaccurate. 7 Heinrich Kulka, Adolf Loos: Das Werk des Architekten (Vienna: Schroll, 1931), fig. 250. 8 M. H. Baillie Scott, Houses and Gardens (London: George Newnes, 1906), 68. 9 Josef Frank, “How to Plan a House,” quoted in Johannes Spalt and Hermann Czech, eds., Josef Frank, 1885–1967, exh. cat. (Vienna: Hochschule für angewandte Kunst, 1981), 156–67, here 163. 10 See Bruno Reichlin, “The Pros and Cons of the Horizontal Window: The PerretLe ­Corbusier Controversy,” Daidalos, no. 13 (1984): 65–78. 11 Le Corbusier, Precisions on the Present State of Architecture and City Planning, trans. Edith Schreiber Aujame (Cambridge, MA: MIT Press, 1991), 130; Le Corbusier, Précisions sur un état présent de l’architecture et de l’urbanisme (Paris: Crès, 1930), 130: “La fenêtre de 11 mètres introduit l’immensité du dehors, l’in­­ falsifiable unité d’un paysage lacustre avec tempêtes ou calmes radieux.” 12 Reichlin, “The Pros and Cons of the Horizontal Window” (note 10), 72. 13 Lois Welzenbacher, “Der geöffnete Wohnraum” (1935), quoted in August ­S arnitz, Lois Welzenbacher, Architekt, 1880–1955 (Salzburg: Residenz, 1989), 169– 71, here 171. 14 See Bettina Köhler, “Phantom Glashaus: Das ‘Un-Private’ als zeitgemässe ­städti­sche Lebensform—ein widersprüchliches Verlangen,” Werk, Bauen + Wohnen 89/56, no. 10 (2002): 20–25. 15 David Whitney and Jeffrey Kipnis, eds., Philip Johnson: The Glass House (New York: Pantheon, 1993), 123. 16 Jeff Wall, Dan Graham’s Kammerspiel (Toronto: Art Metropole, 1991; the essay was first published in 1982). 17 Ibid., 57. 18 Ibid., 59, 61. 19 Uhlig and Wolff, “Vier Spots aus der Kulturgeschichte von Fenster und Tür” (note 3), 20. 20 Susanne Hauser, “Transparenzen: Ein Essay,” in Johanna Rolshoven, ed., ­Hexen, Wiedergänger, Sans-papiers: Kulturtheoretische Reflexionen zu den Rändern des sozialen Raumes (Marburg: Jonas, 2003), 143–56, here 149. 21 Richard Sennett, The Fall of Public Man (New York: Alfred A. Knopf, 1974). 22 Jeff Wall, Dan Graham’s Kammerspiel (note 16), 39. 23 The title of an exhibition curated by Terence Riley at the Museum of Modern Art; see Terence Riley, The Un-Private House, exh. cat. (New York: Museum of Modern Art, 1999). 24 Flora Steiger-Crawford 1899–1991 (Zurich: gta, 2003), 108. 25 Aladar Olgyay and Victor Olgyay, Solar Control and Shading Devices ­( Princeton NJ: Princeton Univ. Press, 1957), 3. The quotation is from Marcel Breuer, Sun and Shadow (London: Longmans, Green & Co., 1956), 117. 26 Reyner Banham, The Architecture of the Well-Tempered Environment (London: Architectural Press, 1969), 158. 27 Theo Schmid, “Die Entwicklung des individuellen Wohnraumes,” Bauen + Wohnen, no. 1 (1947–48): 55–56. 28 Hermann Czech, “Mehr Licht” (1964), in idem, Zur Abwechslung: Ausgewählte Schriften zur Architektur Wien (Vienna: Löcker, 1996), 19–21, here 20.

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Illuminating: Seeing Well and Seeing ­Comfortably Qualities of Natural Light and Rules of Thumb for Design

Ulrich Löw and Theodor Manz, In den ­Gartenhöfen atrium housing development, ­Reinach, Canton of Basel-Country, 1959–60. View from living room into the atrium.

Good Light Planning? When is a building well lit? At first it is tempting to say that it is when the maximum area is illuminated. But this approach leads to large windows, which in turn involve risks of glare problems, poor distribution of brightness, or excessive heat or heat loss. In fact, a logical answer to the issue of good lighting necessitates looking at the broader context of lighting design. Just as architecture is bound by the three categories of use value, design value, and ­experiential value, lighting design has to deal with several levels of the perception of light: a functional, an aesthetic, an emotional, and a somatic level.1 The role of light thus goes far beyond the task of illumination. Rather, irrespective of any functionality and ­objectivity, it must be satisfactory as a sculpting illuminator or generator of certain atmospheres and feelings. Yet the transitions ­between the individual levels are fluid, just as the methodology and specialist knowledge of the architect diminish the further one moves from the rational plane. Before the next chapter moves into the, in a sense, uncertain terrain of questions of the aesthetics and spatial effect of illumina­tion, this chapter addresses the pragmatic side of lighting and hence a practical approach to windows that meets the demands of ­brightness for working, a sense of security, and orientation. Good useful light does not simply make things visible, it also directs the gaze, controls perception, and draws attention to details. It lends objects form and relates spaces and forms to one another. Analogously, in the functional lighting of architecture a further distinction is made between the quantitative and the qualitative objectives to be met. Whereas the former focus on the ability to see or on the rational aspect of making visible—and hence on things such as ­adequate illuminance, optimizing brightness, and homogenous distribution of luminance—the latter are primarily concerned with seeing comfortably. This touches on qualitative aspects such as wayfinding, controlling the direction of light and shadow, and efficient protection against glare. On the whole, therefore, it addresses crucial factors that influence whether a space receives adequate natural light.

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The Given Situation and Local Conditions: Designing the Exterior Apart from the requirements for use and restrictions on the brightness of the space, the planning of natural light is primarily dependant on the availability of natural light. The latter is determined by natural conditions such as climate zone and the surroundings of the building and can be influenced and optimized by orientation, the form of the building, and the dimensioning of the space as well as by designing the exterior space. The key to proper utilization of daylight thus lies in testing climatic relationships or the natu­ral light conditions on site in order to gain familiarity at an early stage of the design process with the limiting conditions for the ­design of the building volumes and the facade. Solar radiation reaches the surface of the earth in two ways: as direct radiation from the sun and as diffuse radiation from the sky. The former is very high-energy light that can be easily directed and focused. In excess, however, it can quickly lead to over­heating, which makes it necessary to take adequate protection measures against sun or heat. Diffuse radiation, by contrast, occurs with a cloudy or overcast sky and is generally considered very comfortable for viewing tasks. Such light is thus ideal for providing ­natural light in interiors. As a rule, however, both components are involved in the lighting of a room. The Climate Zone Depending on the geographical location, the availability of daylight and hence the demands on planning natural light can vary considerably. Determining the sun’s path is essential to predicting the amount of daylight that enters and the passive solar heat yield. Latitude, time of day, and the season can be used to calculate the ­position of the sun for every site at any time, which provides us with initial information about the angle of incidence of solar radiation and the duration of sunshine that should be expected. Another important factor is the dominant meteorological conditions of the sky, which ranges, depending on the climate zone, between diffuse, clear, and overcast. Locations in northern European countries, for example, are ­distinguished by shorter days in winter and longer days in summer. In terms of the availability of daylight, therefore, they are subject to larger seasonal variations than places in central Europe. Because the position of the sun is lower in general, they are subject to ­deficiencies in (sun)light and heat in the winter especially. For that reason, maximizing the influx of daylight is of utmost importance at these latitudes. It is good to know that the overcast sky typ­ ical of the north is brightest around the zenith. The luminance measured there is around three times higher than that at the horizon. In northern zones and coastal regions, therefore, more natural light can be brought into buildings via skylights than with the usual lighting from the side. 2 By contrast, the closer one is to the equator, the more light is available. Sites in southern Europe get far more daylight on average because the sun is higher in the sky. Seasonal variations are far ­lower. The primary goal here is to limit the amount of daylight that enters in order to protect against overheating. When the sky is clear, as it typically is in the south, the brightest areas are around the sun and along the horizon.3

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When planning natural light in central and northern Europe, the diffuse sky is crucial, since the sun is covered by clouds 55% of daylight hours. The supply of daylight is thus primarily in the form of the diffuse light radiation of an overcast sky which is, depending on the weather conditions, supplemented by a certain ratio of direct sunlight. Because a spot with direct sun will appear five to ten times as bright as one lit by diffuse light, strategies for sun shading definitely have to be part of the planning in these regions. By contrast, the sky, whose brightness varies considerably in central European latitudes, provides soft, glarefree light at every hour of the day. It comes from all sides and is also responsible for the light on northern facades. The Building’s Surroundings In addition to climatic conditions, the immediate surroundings, including such factors as the density of building, play an essential role in the supply of natural light at a given site. The main cause for dark spaces is shadows from neighboring buildings, the terrain itself, and the surrounding vegetation. Shade from buildings opposite can be particularly disadvantageous, since the percentage of sky visible through a window is crucial to the proper utilization of daylight. If this is reduced by buildings, it has a correspondingly ­negative effect on lighting conditions in the interior. Early studies of the conditions of the surroundings can clarify a site’s potential ­ for natural light and permit the architect to draw appropriate conclusions about a suitable form for the building and solution for the floor plan.4 The Sun’s Orientation Whenever there is a possibility to choose the orientation of the building, the specific advantages and disadvantages resulting from the position of the building volume should be carefully weighed. The effect of the sun will differ according to the orientation of the individual surfaces of the building relative to the ­compass points, just as the lighting conditions in the interior will differ according to location of the room. Whereas southern light is very intense and dynamic and emphasizes the plasticity of forms, northern light is more constant and cooler. The latter is thus good for bright, even illumination of a space, with no risk of overheating or glare. In contrast to solar radiation (and the ­ex­pected heat increase), it is generally advisable to have the main ­facades oriented to the north and south, which have certain ­advantages over the east and west. That is because the sun in the east and west is generally lower in the sky—even in the summer— which makes protection from the sun more difficult if views out are to be preserved. Windows on the southern facade, by contrast, can easily be shaded by small overhangs because the position of the sun is high in summer. In winter, they get sufficient direct sunlight, despite the lower position of the sun, provided the problem of glare is tolerable and heat from solar energy desirable. It is necessary to qualify this, at this point, by pointing out that recent studies have shown that such an orientation of the building volume and ­design of the facade only make sense in terms of energy if the building is more than 700 meters above sea level. Because of more ­frequent cloudy conditions and higher fog density in the winter

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Schematic rendering of the course of the sun during the year.—The amount of available light varies considerably according to the season in central and northern Europe.

months, strategies to benefit from radiation by choosing an appropriate building form and southern orientation do not justify the additional effort. In such locations it is better to employ a compact construction to minimize heat loss. It can also make sense to orient the main facade of a building to the southeast, so that the benefits of solar heating occur earlier in the day, when the outside and building temperature are lower. This also lowers the risk of overheating in the summer, though glare becomes a bigger problem. The Building Volumes and Facades The orientation of the building and structure of the building volume will establish the main angles of incidence for natural light and direct sunlight as well as the shade conditions of the building. The components that can be used to control light entering the interior are the height and depth of the building, the modulation of the building volume or facade, respectively, and of course the location of window openings. When laying out the height and depth of the building, it is important to keep in mind that only those areas of a room will get light that fall within an angle of thirty degrees to the upper edge of the window. One rule of thumb for rooms lit from the side is that daylight will at best penetrate into the room to about twice the distance from the floor to the upper edge of the ceiling. With a ceiling height of 2.7 meters as is typical in residential buildings, that means 4.6 meters. A freestanding building with standard ceiling heights can therefore receive natural light to a depth of about 10 to 12 meters, provided that both building facades have a sufficient ratio of window area. In addition to the dimensions of the building, the quantity and quality of natural light entering can be improved by modulating the building volume. Fanning out, staggering, or notching the building volume make it possible to increase the surface of the building and hence the ratio of the facade available for windows.

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30°

H

2H

30° rule for a room lit from the side.

Another option is to introduce light wells or atriums, which create situations were light enters from two sides since this can improve lighting if the floor plan is deep. It is, however, impossible to avoid conflicts in objectives, for while a richly articulated building ­volume has great advantages in terms of the available natural light, a compact volume (with the smallest possible ratio of building ­surface and volume) will be far more efficient with regard to heating costs. Similarly, greater ceiling heights will improve natural lighting, but also increase heat loss and construction costs. Finally, the extent to which window openings provide a building with natural light also depends on their size, position, and nature as well as on objects that create shadows. In addition to neighboring buildings and vegetation, parts of the building’s own shell can ­affect interior brightness. That happens, for example, when projections such as balconies or other parts of the facade block the path of light from the sky to the areas of a room being used.

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Quantitative Objectives Interior Design and Functional Lighting It is simplest to begin our discussion of planning by starting with the quantifiable characteristics of natural light in a room and drawing aesthetic consequences from them. It is thus first necessary to explain how natural light—or, more precisely, which of its components—reaches a certain point in the room from the sky.

Daylight factor (%)

The Composition of Natural Light In order to determine the conditions of natural light in an interior, a quantity for measuring the brightness of a room has been es­ tablished: daylight factor (DF). It can be used to compare lighting conditions in a room with conditions outside. This can be useful because when looking out of a window, the brightness of the sky and any surrounding illuminated surfaces will become reference points for assessing the brightness of the room in which one is standing. DF is thus an average value that correlates well with the ­sub­jective description of a space. It has three components: the sky component (SC)—the part of the sky that is visible through a ­window—radiates directly into the room and usually represents, de­ pending on the angle of incidence, the lion’s share of the brightness in a room.5

Distance from window (m)

The daylight factor (DF) in an interior is made up of three components whose ­per­centage varies according to the depth into the room. SC = sky component, ERC = externally reflected component, IRC = ­internally reflected component. The DF ­indicates the percentage of natural light at a particular point in the interior in relation to the amount of daylight ­outdoors. A DF of 5 to 10% is desirable for workplaces.

The externally reflected component (ERC) is the percentage of light that is provided from the surroundings when daylight is reflected into the room by outside buildings. The contribution of ­external reflective surfaces can be significant in densely built urban environments, as when the percentage of visible sky is greatly ­reduced by the height of neighboring buildings. The externally reflected component enters the room at a very low angle, almost horizontally, which enables it to penetrate deeper areas of the space than direct natural light. The internally reflected component (IRC) results from the ­reflection of the first two components with interior surfaces. That means that the light penetrating below the horizontal working ­surface is reflected again by the floor, ceiling, and interior walls, distributing the light relatively uniformly throughout the room. Depending on the depth of the room or the distance from the window, the share of each of these three components will vary. 134

Near the window in a standard room, for example, it is primarily direct sky light that comes into play, in combination with a certain percentage of externally reflected light. These two latter components begin on a high level but describe a sharply falling curve as one moves into the depth. By contrast, the curve of the third component—internally reflected light—begins on a relatively low level, but in return it maintains a relatively constant value up to depths of about five meters. This explains the important role that light reflec­ ted from the surfaces of the room plays in deep rooms, since it ­accounts for most of the natural lighting in the deeper zones of the room—as long as the choice of materials supports it. Terms in Lighting Technology Good visibility is not simply a matter of sufficient (natural) lighting but is also directly connected to the physiology of the eye. Most concepts of space focus on the level of illuminance—that is to say, sufficient brightness. This varies according to the age of the users, the nature of the task, and the reflective properties of the surface of the room. Other aspects of good conditions for seeing ­include uniformity of lighting, a sufficient proportion of directed light to make spatial vision easier, and restricting glare. All of these criteria are subject to standards specified by the Deutsches Institut für Normung (DIN, or German institute for stan­dard­ ization): DIN 5034 and 5035. 6 The central criterion for quantitative planning for vision or functional lighting is illuminance (E), measured in lux (lx). It must be said that the legal requirements to maintain certain limits can put the designer in a difficult situation, since illuminance is a quantity that describes only the luminous flux falling on a surface and can only be measured by photometry. We should not therefore have any great illusions about keeping to lighting requirements in practice, as under ordinary conditions the difference between an ­illuminance of 600 lx and one of 800 lx can scarcely be perceived by the eye. Moreover, the illuminance of natural light is subject to great variations over the course of a day. Illuminance itself cannot even be perceived by the eye. Light obtains an optical presence only when it is reflected by the surface of an object and appears on the retina. This makes the luminance (L) in candela per square ­meter (Cd/m 2) the real basis of visual perception: this is what we actually perceive as brightness. It can only be determined if the specific reflectivity of an illuminated object is known. That means that the luminance or “brightness” that we see is ultimate determined by the illuminance E and the reflectance p of an illuminated surface. Under natural lighting conditions, the daylight coming directly from the sky corresponds to the illuminance that is reflected by the surfaces it strikes in the room. This internal reflection of the light can produce an increase of about 10–20% in the amount of light in the middle depths of the room. 7 Bright surfaces have greater reflectance than darker ones; they pass more light on. The interplay of lighting with the architecture is thus influenced by the choice of materials. The effect of light on the space as a whole can thus be influenced by the properties of the materials such as ­reflection or transmission or scattering. The last of these determines whether a material is more a “light scatterer” (for example, matte

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surfaces such as plaster that give off more diffuse light) or a “light director” (for example, reflective surfaces such as glass that give off more directed light). Observing the different luminances resulting from the surfaces of objects makes it possible to determine the actual brightness conditions in a room. When planning, the primary rule of thumb is that the more difficult the task for seeing, and the smaller the reflectance of the materials, the higher the illumi­ nance of the natural light entering the room must be. It is often ­astonishing to see the extent to which construction materials can “ab­sorb” light. For example, even with the required illuminance, a room with walls of red brick and a correspondingly low reflectance of 25% will seem very dark or unpleasant in comparison with a room with white plaster walls and a reflectance of 85% percent. Dark colors should thus be avoided on large surfaces, especially close to windows, since they reduce the penetration of natural light and can also cause glare in interaction with bright surfaces. 8 There are two ways to influence the perceived brightness of a room or architectural element: by means of lighting intensity and through the choice of the surface qualities of materials. Whereas both these components are common tools for stage designers, architects only rarely make sufficient use of them. The Distribution of Luminance and Transitions Professional light planners usually focus on those aspects of lighting that enable them to create optimal lighting and hence working conditions. Apart from glare, an excess of light is usually out of the question. Glare alone sets limits on the usual striving for brightness. The light planner usually considers the criteria of illumi­ nance, illuminance distribution, and the overall lighting when assessing the lighting technology, supplemented by other factors such as sufficient protection against sun and glare and the views of the outside. The most significant factor alongside the degree of illu­ minance—that is, the amount of natural light that enters—is uniform distribution of light in the room. But the overall lighting is im­ portant as well: sufficient brightness (luminance) for all the surfaces must be provided in the room and the differences in luminance ­cannot vary too much. Planning regulations state that the illuminance distribution is good—that is, uniform—when maximum DF (usually near the ­window) is no more than six times the lowest value in the darkest areas of the room.9 In practice, however, this recommendation is not very easy to follow. Even when DF is tested in various places with an appropriate measuring, the values only apply to the places tested. But they change with every step in relation to the window opening.

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When assessing overall lighting, therefore, it is necessary to f­ ocus instead on the distribution of brightness in various zones of the room. As mentioned above, differences in luminance of the ­surfaces of the objects perceived in the room are crucial to the functional lighting. They are depicted on the retina as an actual pattern of luminance. Whether the object is easily recognizable, how­ ever, depends on whether there is sufficient luminance contrast ­between the object and its surroundings.10 Conversely, the luminances in the viewer’s field of vision or visual field cannot contrast too much, as otherwise visual perception is disturbed by effects of glare. The recommendations are written to focus attention on a certain local uniformity of luminance or on maximum luminance contrast: to prevent distracting the gaze, the area for a visual task or an object has to be brighter than its surroundings. Nevertheless, the contrast between the luminance of the immediate field of vision (the so-called inner field) and that of the immediate ­surroundings should not exceed three to one. For the visual field (the so-called outer field), the recommended contrast with the broader surroundings is ten to one. Particularly with direct sunlight, these recommended values can be considerably exceeded. It is interesting, however, that users’ acceptance of contrast in the lighting of a room is incomparably higher with natural light than with arti­ficial light. Rules of Thumb for Interior Design The extent to which window openings provide natural light in a given interior depends primarily on the dimensions of the room, the position and size of the openings, the reflectance of the sur­ faces, and the influence of the shadows of exterior objects. The Height and Depth of the Room The ratio of a room’s height to its depth is of elementary significance when providing it with natural light. For example, the maximum luminous flux available for lighting is dependent on the height of the ceiling. The question of ceiling height in turn is, as part of the problem of proportions, closely related to that of the ap­ propriate depth of the room. Because of restrictions on ceiling or rather building heights, the latter in particular come to the fore when multistory buildings are planned. Dimensioning the depth of the building volumes thus becomes the most important factor for good natural lighting. Historically, this simple rule was sufficiently known, and many larger buildings have richly articulated volumes, with courtyards, oriels, and projections. When a room is lit from the side, the above-mentioned rule of thumb applies for ­calculating the depth of light penetration. Furthermore, it has to be considered that the quantity of natural light drops off rapidly as one moves away from the window. Whereas the daylight factor near the window usually has a very high value of perhaps 10%, already at two meters away it has dropped to a value of about 2–3%, before reaching a minimum at about 6 meters depth.11 This rule has nothing to do with the position of the sun; it pertains solely to the light in the room provided by the sky. Hence it is valid for all compass directions and seasons, but only when the path of light from the sky to the area of use is not blocked by neighboring ­buildings or parts of the building itself.

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Daylight factor (%)

The 30° rule can also be used for a first estimate of the lighting of a room by a skylight. In that case, it should be assumed that all of the zones that lie within the radius of an angle of opening of 30° beneath the skylight will have sufficient light. This results in an area that is as wide as the height of the room plus the width of the skylight. The area immediately under the opening is very well served by the sky as a light source and will be correspondingly bright.12 Particularly in buildings that are deep but not especially tall, skylights are a good way to improve the lighting of interior spaces considerably.

With light entering from only one side, the amount of natural light will decrease as one moves rapidly further back in the room. Whereas locations near the window usually have very high daylight factors above 10%, the values even 2.3 meters into the room are already considerable lower.

Luis Barragán, Gálvez House, Colonia Chimalistac, Mexico City, 1955. Ribbon window in living area.—Installing a ribbon window with no lintel immediately under the ceiling results in ideal natural lighting in terms of quantity and distribution.

Distance from window (m)

The Size and Position of Windows The size and nature of an opening is not infrequently determined entirely by the amount of light necessary. Often such factors as material and construction; the need for visual shielding, enclosure, and ventilation of a space; and especially considerations of a building’s appearance play a central role when dimensioning and designing windows. Quantitatively ideal lighting is achieved, especially in deeper areas of the room, with a window that is located as high as possible; ideally it should be located under the ceiling without a lintel. If light enters only from one side, a ratio of window area of about 30% in the upper third of the facade is required for proper illumination of the room. The format is less important. In the standard case of a room illuminated from one side, a window area of about 40–50% of the wall area will provide good natural lighting, which represents a DF of about 2% or even more in a room 3 meters deep.13 A ratio of window area under 20%, by contrast, is viewed critically by light planners.14 Increasing the ratio of the window area to 50–60% in response is acceptable, but it does not represent an improvement in terms of lighting. Already with a ratio of window area around 65%, problems begin to emerge with heat insulation in summer. The current trend to all-glass walls sometimes turns out to be a source for thermal discomfort: window surfaces below the height of a desk (80 centimeters) contribute little to the lighting of the room but do contribute to the burden of cooling the building. They should be avoided if they are not absolutely necessary for other reasons. Be that as it may, the rule still applies that the larger the window, the more important the choice of appropriate glazing and the installation of effective solar and thermal control.

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Daylight factor (%)

Distance from window (m)

Influence of window position The illustration shows the same type of window installed at three different heights. The differences in the curve of daylight factors makes it clear that the best distribution of light results from the window located highest on the wall, that is, it has the smallest difference between the highest and lowest values in the room.

Daylight factor (%)

Influence of window shape Three openings with different proportions but equal surface area show that the best curve of daylight factors is generated by the variant with the largest percentage of glass on the upper part of the wall. In this case, it is the window with a nearly square format; at a depth of 3 to 5 meters into the room, it has daylight factors nearly twice those of the ribbon window.

Distance from window (m)

Weichlbauer, Ortis, Housing complex, St. Bartholomä, Styria, 1992–95. Living room.—When the room is lit from only one side, good natural lighting results when the facade is about 40–50% glass. If the ceiling is three meters tall, 30–40% is sufficient if the windows are on the upper part of the wall. Whether or not increasing the percentage of window area will improve lighting conditions depends on the type of room and floor plan as well.

Even apart from visual and aesthetic reasons, full-heigth windows do not make much sense: the section of the window below a working height of 85 cm contributes little to the lighting of the room but makes the building more difficult to cool.

Vertical or Horizontal Openings In his “Five Points toward a New Architecture,” Le Corbusier praised the supposed advantages of the ribbon window over the traditional vertical window: “In this way, rooms are equitably lit from wall to wall. Experiments have shown that a room thus lit has an eight times stronger illumination than the same room lit by

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Sketches by Le Corbusier illustrating that the ribbon window allegedly provides ­more and better light than the traditional vertical window format—and is also the logical consequence of a modern approach to architecture.

v­ ertical windows with the same window area. The whole history of architecture revolves exclusively around the wall apertures. Through use of the horizontal window, reinforced concrete suddenly provides the possibility of maximum illumination.”15 In fact, this generalized statement is not even correct in the specific case Le Corbusier was discussing. The ribbon window at the height of the balustrade he was describing provides good, uniform illuminance distribution along the facade but does not adequately ­illuminate the depths. His claim that the horizontal ribbon window results in illumination values eight times higher than a vertical ­window is just as inaccurate as the lighting properties he attributes to it. Such an assertion, which neither makes distinctions nor ­establishes limits as for which points in the room it holds, implies to laypersons that the entire room must seem eight times brighter when a horizontal window format is employed. In reality, the decision for a vertical or horizontal window has to be examined on a case by case basis. Even if the ratio of window ­area remains the same, the illuminance distribution in a room will vary depending on the position of the opening in the wall. Nevertheless, a simulation by British planners has shown that sometimes two vertical, narrower windows with a solid area between them will result in better lighting conditions overall than a ribbon window at medium height with an identical ratio of glass.16 Compared to the latter, the vertical windows will have a larger percentage of the window surface in the highest part of the wall. That has a positive effect on the illuminance distribution: not only does the light penetrate into deeper zones of the room, it is also more uniform. In addition to the function of lighting interiors, views out and visual contact with the surroundings are important criteria for comfort. Hence the nature of activity in a given room and the primary direction of viewing should also be considered when deciding on the dimensions and placement of a window. In DIN 5034, the primary viewing direction of a person sitting in a room leads to a recommendation that the lower edge of a window for viewing

In this example with a southern orien­ tation, the two vertical windows offer a more uniform lighting of the depths of the space when compared to a ribbon window, since a larger share of the window surface is on the upper part of the wall. In general, however, good lighting is less a question of format than of the share of the opening above the work surface (hor­ izontal axis: distance from the window in meters; vertical axis: illumination in lux).

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be placed 90 centimeters above the floor; the upper edge, by contrast, should be at a height of about 2.2 meters. That results in a minimum height of 1.3 meters for a window, including the width of the frame at top and bottom. The opening should be at least 1 meter wide. Occupants usually prefer wider window formats,17 especially when there is an interesting view of nearby objects or zones of activity. The place of a window should, in any case, be carefully con­ sidered, with preference given to complex situations with changing motifs over static subjects. A view only of the sky—as is often the case with high ribbon windows and skylights—is not sufficiently interesting. Window formats that offer a view of the horizon are more attractive.

Sketches showing the distribution of light through various window formats produced by R.G. Hopkinson: “A high window gives better light penetration than a long low window for the same area of glass.”

Weichlbauer, Ortis, wohnDNA, Gratkorn, Styria, 1998–2001. Interior, view, windows placed for a variety of prospects.—A wide variety of window modules are employed all over the building whose placement height and format different according to the use of the space and the occupants’ activity.

Kitchen

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Children’s room Master bedroom Study Living room

Dining corner

Alfred Roth, Emil Roth, and Marcel Breuer, Doldertal Houses, Zurich, 1932–36. Alfred Roth’s live-in studio, Doldertal 19.—The ribbon skylights are an especially effective lighting technology (though they require good solar control). A second window at viewing height provides the necessary prospect.

To achieve proper lighting conditions while minimizing glare it can be helpful to divide the functions of light and view between two different window formats. Broad ribbon windows in the upper part of the wall not only provide uniform and bright lighting of the room, thanks to their more effective lighting of the ceiling, but they also make sense where the goal is to remove the light source from the occupants’ direct field of vision. The resulting lack of visual connection to the surroundings can be compensated for with an ­appropriately sized viewing window at eye level. Particularly when the activities in the room require an atmosphere with little contrast, such a combination can prove extremely practical. Shadows of Other Buildings The natural light in a room can be considerably diminished by shade from objects outside. In addition to neighboring buildings and ­vegetation, parts of the building’s own shell can affect interior bright­ ness. That happens, for example, when parts of the building that project horizontally over the opening, such as balconies and slats or opaque parts of the facade, block the path of light from the sky to the areas of a room being used. The buildings opposite in particular can massively reduce the amount of light that reaches the back parts of a room. The following rule of thumb is appropriate for a first check of the shadow conditions caused by other buildings: For a ­ratio of the distance D from the neighboring building and the build­ ing’s height H, the resulting figure indicates the degree of reduction. Values of D : H greater than 2.7 do not represent a reduction and values between that and 2 only a small one. Values of 1 and below, by contrast, indicate a considerable reduction. For rooms facing a courtyard or atrium, the same rule applies. Obstructions on the side from neighboring buildings or parts of one’s own, angled building, can also block a great deal of light, but only in the front part of the room. It is important to consider that in the corner of an angled floor plan, the first 8 to 10 meters will be less well lit. Balconies or fixed shading systems attached horizontally about the window can also be light sponges, especially on dark days. Viewed solely from the perspective of light planning, balconies of apartment buildings should not be project more than absolutely necessary and as much as possible should not be located over

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When choosing the appropriate window type, it is important to take the situation of the surroundings into account in the ­planning. The most significant factor in lighting conditions at a particular point in the room is the percentage of the sky ­visible through the window (angle of incidence of direct light from the sky). SC = sky component, ERC = externally reflected component, IRC = ­internally reflected component. Baumschlager & Eberle, Residential devel­ opment, Nüziders, Vorarlberg, 1995–96. Projecting winter gardens on the southern facade.—Regardless of the number and format of the windows, the interior lighting can be considerably diminished by shadows from exterior objects.

glazed areas of the apartments below. Competing interests need to be weighed here. Moreover, seemingly simple interventions in the skin of the facade should not be underestimated. They can lead to unpleasant surprises in the illumination of the interior. That happened, for example, when an apartment block in Germany was ­renovated, and the existing balconies were glazed to conserve energy. This led to a massive reduction in the amount of natural light ­entering the interior, and the parties concerned were astonished to discover that values dropped 30–45%.18 Finally, to sum it up in simple planning terms: proper interior illumination is, apart from sufficient ceiling heights, dependent above all on the ratio of window surface above the level of work sur­ faces or the ratio in the upper area of the wall. The form of the ­window plays less of a role. In practice, it is important that the real circumstances of the surroundings be considered at the planning stage when choosing a suitable opening. This is the only way to specify correctly factors determining the lighting conditions in the interior, such as the percentage of the sky visible and the specific angle of incidence of light entering the room.

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Increasing and Optimizing Light The use of natural light in architecture is a subtractive process, because only part of the daylight reaches the interior of the building. Often, however, additional natural light or improved distribution would not only increase functional lighting but would also reduce electricity costs for artificial light. In the section that follows, therefore, we will sketch ways to optimize illuminance. Beginning with lighting from one side and moving on to lighting from more than one side, various examples will be used to show how the amount of natural light entering the building interior can be increased and controlled using simple but effective architectural ­measures.

Sun

Light

Solar control prism

Daylight factor Relationship to outdoors

Optimal use of natural light thanks to a ­reflecting system: Daylight with a large pro­ portion of light from the zenith falls through a skylight onto a mirror that re­ directs it into the room. At the same time, the interior reflecting segment on the ­ceiling extends the light into the rear part of the room. The lower window serves ­only to provide a prospect—the view of which is chosen such that no disturbing exterior luminances (e.g., reflections from neighboring buildings or snow) enter the visual field.

Light from One Side Optimum: The high ribbon window. If we begin with the simplest and probably most common case—namely, light entering from one side of the room—the quantitative objectives of light planners are best met with a sufficiently wide ribbon window, which extends across as much of the wall as possible and meets the ceiling without a lintel. Such an arrangement not only maximizes illuminance, it also ensures that the distribution of light and brightness within the room is as homogeneous as possible. If the wall is also given an additional window at viewing height, the necessary view out is also provided. That this sort of optimized arrangement of windows can be justified in residences is demonstrated by the clever solution of the so-called keyhole window by Louis I. Kahn. In the twostory living room of the Esherick House, the inside wall on the northeast facade has a large bookshelf, while the window placed above it, which is flush with the ceiling, provides uniform lighting. A vertical slit window in the center supplements the high ribbon window to create a T-form and provides ventilation and a view. This double form—or rather double function—of the window is a motif often employed by Kahn, which he varied according to the orientation and use of the room. Here it serves the activity of reading and at the same time creates a pole of calm in the room.

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Louis I. Kahn, Margaret Esherick House, Chestnut Hill, PA, 1959–61. Northwest side of the living room with keyhole ­window.—The so-called keyhole window— which Kahn invented—has a dual function. The horizontal ribbon window flush with the ceiling provides generous light; the vertical format at eye height ensures a view outward.

As necessary, the crenel-like window can also be closed, which turns the bookshelf into a high wall and lends the room an introverted character. Re-directing light (indirect light via reflection). Into the ­t wentieth century it was generally believed that only daylight coming directly from the sky determined the illuminance distribution and quantity of light in a room. Today, by contrast, we know that the reflection of light on (bright) surrounding surfaces can ­increase the daylight factor in the middle zones of a room by about 10–20%. That is also why modern light planning seeks above all to maximize the amount of reflection in the interior. As noted above, such reflection is relatively constant within the room and can be an important factor in reducing powerful contrasts of light and dark when the supply of light to the center of the room drops off rapidly. In most cases, it is the surfaces of the wall that contribute to lighting deeper areas of the room. Usually they receive direct light from the sky or even the sun and, if they are appropriately re­flec­ tive, become a secondary source of light, radiating the light back into the room. In open floor plans, where few interior walls contrib­ute to reflection, the ceiling becomes the main source of reflection. 145

This necessitates, however, that it be painted a bright color and be kept free of beams and the like.19 The lighting of the ceiling occurs only indirectly, above all from the floor, which reflects the ­incoming daylight onto the ceiling, and from external reflection. An external surface of an appropriate material can become an important source of reflection that can influence the interior lighting conditions via the ceiling. For example, in many of his projects Richard Neutra used a pool of water in front of a glass facade to capture the changing lighting of the sky and direct it into the room. His concern was not so much increasing the lighting in the room as the aesthetic effect of the reflections. Another way to bring the ceiling into play as an important ­secondary light source is to widen the windowsill into a ledge 20 to 30 centimeters across. If painted brightly, it will reflect some of the natural light that enters onto the ceiling, which reflects it back, glarefree, down into the room. This tried-and-tested measure, which fell into oblivion with the smooth facade of modernism, not only helps improve the illuminance distribution of natural light but also controls glare.

Miller & Maranta, Renovation of the Villa Garbald (Gottfried Semper, 1862–64) and expansion of an ETH seminar room, ­Castasegna, Bregaglia, ­Can­ton of Graubünden, 2002–4. Roccolo expansion.— The color and material of walls can ­influence how much light the zones away from windows receive, especially if the walls get direct sunlight. Richard Neutra, Chuey House, Los Angeles, CA, 1956. View from the southeast.— The reflecting quality of bodies of water, however small, can be used to increase ­natural light.

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Light shelves on a residential and ­commercial building in Zurich-Seefeld.

The professional variation on this is the so-called light shelf, which follows the same principle and can be integrated into the design of the facade. A horizontal, smooth, brightly painted surface ensures that daylight is directed toward the ceiling. The penetration of natural light into the room can be increased by more than 5 meters, which corresponds roughly to 2.5 the distance from the floor to the upper edge of the window, as opposed to the usual 1.5 to 2 times. At the same time, light shelves protect against direct sun radiation near the window. They work best on the southern side in latitudes dominated by clear skies. The arrangement of the window openings and the incorporation of reflective surfaces can also influence the intensity of luminance and illuminance distribution in the room. This latitude will be limited, however, as long as the typical ceiling height in relation to the depth of the room is too low to be of much effect where natural light is concerned. Real progress in natural lighting calls for new solutions, especially for multistory apartment buildings. Until now, the question of what they could look like has been left to the ­innovative spirit of a few pioneers. Beveling of lintel and parapet. From the perspective of the light planner, the extension of the ceiling of each story into a taper­ ing or ­rising console can be a simple but effective way to improve ­considerably the influx of natural light. It makes the room taller and more open with respect to the facade, which ­increases the amount of bright zenith light that enters and allows it to penetrate as much as 6 meters into the room. 20 As far back as the early 1930s, Alvar ­Aalto employed an analogous solution for the ­­south-facing patients’ rooms of his sanatorium in Paimio. Very much in the spirit of ­modernism, which believed in the healing effects of surroundings drenched in light and sun, the slabs of the floors were bent upward to allow light and sunbeams to penetrate more deeply, ideally up to the head of the hospital beds. This ­carefully con­sidered detail was, however, not implemented, for ­reasons of cost. That a corresponding approach to improving natural light is (economically) possible is demonstrated by an example from contemporary residential architecture. The young Viennese architectural office querkraft used upstand beams instead of the usual downstand beams to minimize the shadows falling on the windows from the projecting balconies. At the same time, it improved the penetration of natural light into the interiors. The quality of the lighting is also enhanced by the broad windowsill attached to the upstand beams. It reflects the sunlight directly into the room.

Ceiling lamps and natural light in patients’ rooms.—One of Aalto’s many functional drawings relating to the control of the lighting in the sickbays—based on the needs of recumbent occupants.

Alvar Aalto, Tuberculosis sanatorium, ­Paimio, Finland, 1928–33. North-south section through the patient wing (prelim­ inary project).—As this section from an early stage of the planning demonstrates, Aalto originally intended to bend upward the ends of the ceiling of each story of the patients’ rooms to allow the light to penetrate more deeply.

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querkraft, LEE residential building, ViennaFavoriten, 2001–4. Living room with upstand beam, section of facade area, facade with graphic of the balustrades (Lichtwitz—Büro für visuelle Gestaltung).— A minimal intervention in the cross section of the building improves the incidence of light. The balcony slabs arranged 45 cm above the floors of the apartments can be used inside as a bench or shelf; there is room for a heater underneath them. Exterior sun shading can be placed under them without being seen from inside.

Playing with ceiling heights: The maisonette. A leap past the traditional understanding of architectural space as a stacking of independently articulated floors is demonstrated by the Thonik residential and studio building by MVRDV in Amsterdam. Although the reasons for its terraced cross section will scarcely have had anything to do with light planning, the slope of the floor down to the center of the room correlates with the path of the natural light that enters. Also the architects of archiguards have broken with traditional layering. For their vacation home in the Döbling district of Vienna, which was built under considerable cost pressures, the difference in levels of the ceilings separating the floors causes the two volumes to dovetail. The two levels obtain a surprising generosity of living space. The idea for the space resulted not just from playfulness but from functional necessity. It evolved from the circumstances of the site: a sloping terrain. Hence the broad spatial terrace in front of the framed landscape window on the upper story does not just heighten the drama of the room (and the reflected light) but also makes sense on the lower floor, where it surrounds a ribbon window that provides light. For a duplex in Utrecht, also by MVRDV, all of the conventional approaches to horizontal and vertical separation were thrown overboard. The three-dimensional bracketing of the two apartments not only causes them to seem larger than the number of square meters indicates but the lighting conditions in the interior also benefit from the partial increase in ceiling heights. 149

MVRDV, Thonik residential and studio ­building, Amsterdam, 1998–2001. View, interior of upper story, section.—­ Cross sections of the space can be formed to take into account the characteristics of the incidence of light. Here the ceiling height of the ground floor decreases from 4 to 2.5 meters in half-meter steps, increasing likewise on the floor above. One advantage, in addition to lighting, is the spatial diversity resulting from the ­section.

archiguards, Vacation home, Vienna­Döbling, 2000–2002. Living area on the upper story and transition zone to the ­terrace on the lower story, north-south section.—Subtle use of the sloping terrain versus conventional layering.

MVRDV, Two-family home, Utrecht, ­ 1995–97. Facade facing street, interior, and vertical arrangement of space.— The meandering bracketing of two homes results in narrow layers of space. The lighting conditions benefit from the in­ creased heights of certain parts.

Le Corbusier, Unité d’habitation, ­Marseilles, 1945–52. Section of duplex ­resi­­­­­­dential units nested around a central access corridor, two-story living room with loggia and brise-soleil.— From the perspective of light planning, the maisonette type offers unsuspected ­possibilities that result from playing with heights.

Delugan Meissl Associated Architects, Kallco Wienerberg City Lofts, Vienna­Favoriten, 2002–4. Section.—The three­dimensional nesting of various residential units makes it possible to add an additional story to the northern cross ­section without exceeding the permitted building height.

Although the examples discussed here are small buildings, the principles they employ, such as a more highly differentiated ­approach to ceiling heights, can certainly be applied to multistory apartment buildings. If the upper story of a duplex apartment like that of Le Corbusier’s Unité d’habitation in Marseilles is turned into a gallery and only partly covers the room beneath it, the ­apartment will benefit from light entering through the doubled ceiling height that results from the spatial bracketing. It is, however, important to pay attention to maintaining a favorable ratio of height to depth. If the units end up very deep and narrow as in Le Corbusier’s didactic example, only the zones of the room imme­ diately in front of the window are sufficiently brightly lit. Delugan Meissl managed to overcome the limitations placed on light planning by standardized ceiling or rather building heights for their residential building on the Wienerberg in Vienna. By raising the ceiling heights on the south by 3.38 meters, the lighting in the middle zone is optimized in the narrow high-rise, which is about 14.5 meters deep. The ceiling heights of the bedrooms and subsidiary rooms on the north wing, by contrast, are limited to 2.38 meters, which made it possible to add an additional story and remain within the specified building height. The differences in ceiling heights, which take into account the contrasting lighting qualities of the north-south-oriented high-rise, leads to a clear division into day and night zones. Depending on one’s standpoint, this can be seen as an advantage or disadvantage of these apartments. On the whole, the potential of residential buildings conceived in section lies not just in improved lighting but also in their more highly differentiated spatial qualities, which counteracts the one-sidedness and monotony of the usually stacked mass-produced wares. Light from More than One Side Optimum: Windows on two sides. As mentioned above, the depth of lighting possible with windows on only one side is very lim­ ited, especially when skies are overcast. The placement of several windows can overcome the problem of irregular illuminance distribution. Rooms lit from more than one side will have more areas that fall within the middle level of illuminance. Even adding a single opening will suffice to reduce the contrast between bright and dark zones. Light that enters a room from at least two sides significantly improves the perception of contours. If the illuminance ­distribution in the room should be as uniform as possible, a symmet­ rical distribution of the windows is preferable. From the per­ spective of the light planner, therefore, a room that receives light from two openings on opposite sides or, better still, from all four walls, is ideally lit. In the usual case, where there are no special visual requirements for the environment, this is less important. In residential buildings in particular, light entering through windows on the directly adjacent wall is not only completely sufficient but can even be very charming and atmospheric, because not only the quantity of light but also its quality is different on either side. Thus proper lighting by no means demands only large openings.

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The articulation of the open area—which makes up 15% of the space in each of the four examples—affects the light distribution. It is most uniform when the ­openings are symmetrically arranged. In rooms lit from only one side, adding just a single small window to the back wall will considerably improve lighting levels and the distribution of light within the room. As a rule, many small openings are better than one large one (horizontal axis: dis­ tance from the window in meters; vertical axis: illumination in lux).

More elaborate facades. As far as the form of the building is concerned, the logical consequence of a call for light from more than one side is more elaborate facades. If there is indeed sufficient exterior surface available to capture natural light, the building volume can be articulated with corners or receding angles in such a way that light can enter the rooms from two different sides as much as possible. As already noted, this necessitates a greater proportion of facade in relation to building volume than an optimization of heating requirements would permit and thus has to be balanced with possible additional heating costs. When designing floor plans for residential buildings, it is impor­ tant to keep in mind that every room is arranged to border on the exterior on at least two sides. If the building volume is not too deep, one option is to arrange the rooms at an angle to the axis of the building, so that they face both sides of the building. 21 For larger residential buildings, a fanning or notching of the building volume is almost unavoidable if the corner positions ideally suited to lighting concerns are desired. Juxtaposing small and larger rooms can prove helpful here. More problematic, by contrast, is lighting very deep floor plans, though here too lighting from two sides is possible. 154

Lux Guyer, Villa Boveri, Zurich, 1931–32. Music room on attic floor; side niches ­facing south.—Windows on two sides are particularly appealing, not only because of the quantity of light but also because the quality of light from both sides always ­differs.

Buchner Bründler Architekten, Loft house, Colmarerstrasse, Basel, 2000–2002. ­Bathroom with coated glass wall.—Light from two sides thanks to an interior ­window.

Translucent building elements. Similar illumination of a space can be achieved through indirect lighting—for example, by di­ recting natural light from adjacent or external spaces through glass walls or doors. Although indirect light from an interior window scarcely improves the daylight factor in a room, it can achieve better illuminance distribution. 22 Playing with the depth of the room: The atrium. Another approach is found in the typology of buildings: atriums or courtyards are another option for large multistory buildings to create rooms that receive light from more than one side. Although it is a traditional type, it is hardly ever employed for residential buildings around here, probably because occupants are only willing to accept the loss of views into the distance in areas of high urban density. The open courtyard lacks the atrium’s climatic advantage of a roof, and so a larger percentage of the facade is exposed to the climate ­outside. In return, however, there is no reduction of natural light, as there is with a covered atrium, where the glass of the roof re­ duces the intensity of the light that enters, and hence the potential for natural light in the rooms on the atrium side. 23 So although the exploitation of daylight is considerably improved by courtyards, atriums provide temperature benefits in winter. 24 In both cases, however, the important thing is that effectiveness of lighting depends above all on the height and width of the atrium or light well as well as the reflectance of the opaque parts of the facade bordering it. 25 155

Steidle Architekten, Residential development, Mainz-Lerchenberg, 1990–94. ­Section, floor plan of typical floor, view.— Providing light from two sides through the use of atriums: With very deep lots, this can be a good way to provide light from two sides in adjacent rooms. For the use of natural light to be effective, however, the height of the courtyard has to be less than twice its width. Moreover, the ­problem of shadows has to be given utmost priority.

Only atriums or light wells that are not too high or those that have sufficiently broad openings for light to enter (a minimum ratio of width to height of 2:3) are suitable for ordinary residential ­purposes. Built examples are often based on an unjustified optimism about their potential to provide natural light. 26 If natural light is to be optimized, the light well has to be planned very carefully. For example, the ratio of window to wall on the facades should decrease from top to bottom, because the lower stories are, since the angle of incidence of light is greater, more dependent on reflection for their natural light. But if the atrium walls of the upper stories have large windows, the average reflectance of the atrium will be reduced—after all, the reflectance of glass is only 15%. The more glass there is, the lower the reflected radiation that is so important for lighting the lower floors. One of the few buildings to follow this precept in a sensible way is the residential and commercial building on Schützenmattstrasse in Basel by Herzog & de Meuron. The walls that taper cascade-like on the northeast and especially the southeast side of the courtyard provide sufficient surfaces for reflection. This is not just to the benefit of the entire courtyard; the multiple reflection also serves to illuminate the individual apartments that get their light from the atrium. In return, the lower levels profit from the decreasing ratio of window area, which improves the incidence of light on those floors. In general, the entire layout of the floor plan takes into account the characteristics of the incidence of natural light. From the cross section it is clear that the floors on the ­northwest side are staggered back toward the top. The building testifies to subtle planning whose every detail aims to provide opti­mal natural light. It demonstrates perfectly how the planning of natural light can meet the highest aesthetic goals as well. 156

1m

1m

5m

5m

10 m

10 m

Herzog & de Meuron, Residential and commercial building, Schützenmattstrasse, Basel, 1991–93. Northwest-southeast and northeast-southwest sections, view of courtyard and apartment, floor plan of third story.—This long building volume is composed of U-shaped floor plans that surround an atrium on three sides. The atrium gets wider downward, and the floors on the northwest side are staggered back toward the top to increase the amount of natural light available to the lower units. The cascadelike tapering of the facades provides sufficient surfaces to reflect the light, especially in the upper areas.

Qualitative Objectives Interior Design and Seeing Comfortably Although high illuminance supports functional visibility, that is by no means enough to ensure visual comfort and a pleasant ambi­ ance. One of the doyens of light planning, Christian Bartenbach, has described human beings as visual beings who take in through their eyes about eighty percent of the information relevant to their decisions and behavior. Light can help with spatial orientation by marking zones in space, emphasizing architectural structures, and placing them in a functional context. Good planning for natural light is distinguished by lighting conditions in a room that provide the users with the precise amount of information to direct their attention and further the process of perception. Light for Information and Wayfinding Stronger and weaker lighting can produce a hierarchy of infor­ mation that leads the eyes to bright zones or objects and accordingly calls for a darker environment. As already mentioned, it is not just planning the incidence of light and placing and sizing window openings that constitute important design tools but also the choice of surface textures and colors. Whereas too little information may cause the space to seem boring and can make visual tasks more difficult, an excess of information can produce confusion and fatigue.

Christian Matt, Residential building, ­Bregenz, 2000–2003.—Light not only makes it easier to find one’s way but also turns cramped spaces into open ones.

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The quality of light plays a more important role in processing information than is generally recognized. People often try in vain to correct poor visual conditions by increasing the amount of light. Those who think they cannot see something well usually ask for more light. That quantity is not as important as quality, and that bright illumination of a room does not make perception easier is clear from the following picture: if two bright walls standing at a right angle to each other and forming a corner are uni­ formly lit, it can happen that both sides seem equally bright. Under certain circumstances, that can obliterate the edge. If, by contrast, one of the lights is dimmed, so that the lighting of the two surfaces is fundamentally different, the edge will stand out clearly— even if the lighting is very dim. This example shows how lighting situations with poor contrast can flatten contours and thus ­illustrates the importance of shadow as an accomplice to light. The gradation between bright and shaded surfaces is what provides us with information about the plasticity of solid bodies. The way something is lit is of fundamental importance, and it contributes to thinking, acting, and feeling comfortable in a room. The goal of good lighting design must therefore be seeing comfortably. That is the result of a successful combination of adequate brightness and visual attractiveness. Apart from the question of prospect, this ­results primarily from criteria such as the degree of shadow and the luminance distribution or luminance contrasts in the room. In ­contrast to quantitative light planning, where functional vision and hence illuminance is the focus, there is no dominant criterion for qualitative light planning. In addition to the criteria already men­ tioned, the reduction of glare phenomena (and sufficient protection against sunlight) is important in any case, as they represent the primary obstacles to seeing comfortably.

Light and shadow determine how spatial plasticity is perceived.

Directing Light and Shading In the discussion of quantitative light planning, we noted that the uniformity of illuminance distribution is an essential criterion for good visibility. Against the backdrop of the physical perception of space, which is what ultimately accounts for whether a viewer will see comfortably or not, this requirement has to be qualified somewhat. Recognizable contrasts are the basis and prerequisite for our perception of space. A certain amount of shadows increases the plasticity of a room and the objects found there. Shadows occur where, for geometric reasons, little or no light can fall. A distinction is made between the self-shadows and cast ­shadows of objects. The former lie on the object itself; surfaces of a body that do not receive direct light lie in self-shadows. Cast ­shadows, by contrast, are cast by the object onto its surroundings. They result when the light directed by openings falls on an object. Cast shadows can tell us something about the position of the light source but also about the relationship of various objects to one another. The crucial factor for the path of light and the nature of shadow formation is above all the direction of light that dominates in the room, which is why the distinction between directed light and diffuse light is a central criterion of qualitative objectives. Directed light radiates from a point source—from the sun, for example—and it enters interiors through small openings. In con-

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The term “shadedness” describes both the distribution of incident light and the ­capacity of an existing lighting situation to depict three-dimensional forms. Shaded­ ness is an important component of visual performance though frequently it is not considered a such—probably because it is difficult to describe and measure.

trast to the diffuse light of an overcast sky, it produces shadows and reflections in space. Near the window the shadows usually have sharp outlines that become softer as one moves away from the ­window. The advantage of direct radiation is comparatively high ­illuminance, which can improve perception of the three-dimensionality of objects and thus of spatial vision. Direct sunlight has five to ten times as much illuminance as an overcast sky. When the sun is shining and the light enters the room from only one side, hard contrasts result that reduce the information about objects and details. In users’ assessments of living spaces, sunlight—which is inseparably connected to the natural light conditions in the in­ terior—is nevertheless rated highly. Diffuse light, by contrast, is radiated from large luminous ­surfaces such as an overcast sky or from reflecting exterior and interior walls. The surfaces of a room are particularly crucial to ­lighting levels as secondary radiators—that is, as sources for indirect light in interiors. Because of its intense scattering effect, this type of lighting is distinguished by a certain homogeneity. When light comes from several directions, contrasts are lessened or ­balanced out entirely. Disturbing reflections from shiny surfaces or undesirable shadows are largely avoided (this is, by the way, one reason photographers always work with reflected light). With diffuse light, however, high illuminance can only be achieved with con­ siderable effort. Modeling Space The arrangement and surface structures of openings and delimiting surfaces can influence the relationship of direct and indirect light and hence the modeling of space. Currently there are no standard natural planning guidelines to indicate what good modeling consists of and what measures support it. In homes especially, however, there really is not good and bad, but there should be a certain freedom of lighting, which should be dictated entirely by the needs and desires of the occupants. Any lighting situation can have its charms, and the combination of various effects can give the home a desirable variety. It is certainly worthwhile to give some thought to the extent to which the relationship between the ratio of opening to wall has an effect on the lighting conditions and ­shadows in a room and how they can be manipulated in one direction or the other by simple architectural interventions. Last but not least, they are intended as a reminder to be aware in advance of the consequences of certain decisions.

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The directed light that falls through the small window causes the wall’s texture to stand out relieflike and divides the surface into areas of light and shadow that can be precisely perceived. Luis Barragán, Gilardi House, Tacubaya, Mexico City, 1975–77. Gallery.—The sunlight that falls through the slits is refracted and filtered by them and, reflected by the back wall, radiates into the room dif­ fusely. Hard shadows are avoided.

Reducing Contrast A room enclosed by four walls that receives all its light from a relatively small window placed in the middle of a wall will be exceptionally rich in shadows and hence in contrast. In such cases where the light entering is relatively focused and is localized in a speci­fic place in the room, much like a spotlight, the differences in lumi­ nance will range widely. Adding a second opening. Brightening shadow or reducing ­contrast can be achieved by increasing the amount of diffusion radia­ tion in the room. One of the most efficient ways to achieve this is to add another opening. Ideally, it is placed on the adjoining wall, if possible in such a way that light from each side falls on the ­neighboring wall. A properly placed secondary light source not only increases the amount of diffuse light but also the overall brightness level in the space, which can also help to balance the existing contrast between the bright window areas and the darker limiting surfaces. In rooms lit from more than one side, a larger percentage of the room will be in the middle range of illuminance, and even a small window at the back wall will suffice to reduce contrast effectively. If at all possible, corner situations should be ­exploited and given openings in order to bring natural light into the room from various directions.

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Le Corbusier, Cabanon Le Corbusier, ­Roquebrune-Cap Martin, Côte d’Azur, 1951–52. View facing Roquebrune.—­ The room is lit from a single, concentrated light source, which can lead to heavy ­shadows. Much of the room’s sculptural effect can consequently be lost in the semidarkness. Light entering from two sides in a room in the Palazzo Salis, Bondo, Bregaglia, ­Can­ton of Graubünden, 1765–74.

Carlo Scarpa, Gipsoteca Canoviana, ­Possagno, 1955–57. Corner window.— A solution that avoids the effects of backlighting. In this unusual example, the ­modernist corner window—turned inside out—becomes a source of uniform light. The walls meet at right angles, which distributes the light.

Slits rather than holes. Wherever it is possible to light a room via more than one opening, another planning trick can increase the amount of diffuse light and thus contribute to softer lighting conditions with fewer shadows. For example, if the window is moved from the center of the wall to the edge, the flanking side walls becom­ ing sources of reflected light that send the daylight that falls on them back into the room as diffuse radiation. Re-directing light using reflective surfaces. Another option is to employ adjustable shutters attached to the edge of the window in the interior. They function as a reflective surface to radiate light diffusely into the room. If the shutters are divided into fields, the amount of light entering can be regulated progressively. Refraction of light. Moreover, especially in regions further south, the use of brises-soleil mounted outside or wide roof projections to reduce contrast in the interior can considerably reduce the amount of direct radiation. 162

Luis Barragán, Prieto López House, ­Jardines del Pedregal, Mexico City, 1950. Hall.—This principle of breaking through the wall up to the corner turns a vertical wall into a diffusely radiating ­reflector.

Luis Barragán, Barragán House and Studio, Tacubaya, Mexico City, 1947–48. Bedroom with corner window on upper story.— ­Inside shutters, a common architectural element in traditional ­Mexican architecture, enable occupants to control the mix of ­direct and indirect lighting. E.Maxwell Fry, Government Press, Chandigarh, India, 1956. Adjustable aluminum slats for sun shading on the southwest ­facade.—A system that is of particular ­interest in areas with lots of sun.

Modulating Diffuse Brightness By contrast, rooms that are delimited by semitransparent panels that filter the incoming light have a very diffuse brightness. Indirect light dominates, and the result is a soft light that gives viewers the impression of flowing forms and makes the room seem weightless. Undesirable diffusion can be overcome by making some of the ­surfaces of the facade entirely closed, so that they provide shadows. They should be arranged to counteract a uniform and ex­ tensive ­radiation of surfaces in the interior, which would undermine the modulation effect in general. Luminance contrast is further improved if the wall element is also perforated.

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Paul de Ruiter, Mercator 1 research ­building, Katholieke Universiteit Nijmegen, Netherlands, 1996–98.—Broad, uniform lighting of the room counteracts shadows; plasticity disappears.

Perforation. A somewhat unusual solution is seen in an apartment house in Paris in which the architect decided to use slit ­windows of various width in the walls instead of an all-glass facade in order to increase contrast and contours in the rooms and still ensure sufficient light enters even on lower floors. Although this visually appealing solution was chosen primarily in order to prevent unwanted views into the units and to protect their private sphere, it illustrates very well one of the many possibilities for ­balanced lighting conditions to be found among the otherwise rather unimaginative monotony of residential architecture.

Franck Hammoutène, Residential block, rue Raymond Aron, Paris, 13th arrondissement, 1998–2000. View and interior.— Windows as slits in the wall result in higher contrasts and more contours in the room. Kazuyo Sejima & Associates, Y-House, Katsuura, Chiba, Japan, 1993–94. Dining room.—The black surface absorbs the light that enters through a large area.

Absorption. Another, rather simple method for reducing the amount of diffuse light in a room is the use of materials or colors that absorb light such as black paint, slate, or exposed brick, which goes hand in hand with the use of surfaces with low reflectance. In summary, it is possible to create pleasant lighting situations by using several light sources with different characteristics of ­distribution and thus to balance the components of directed and dif­ fuse light. Accordingly, a lighting concept should be developed that takes light from direct sources and combines it with internal re­ flections in order to create a balance between the overall brightness level and the individual lighting accents in the room. 164

1

2 2

Direct glare (1) and glare by reflection (2).

Glare Control Glare is a kind of visual noise that interferes with vision. In any discussion of natural light, the problem of glare deserves par­ticular mention, and the reduction of glare is an essential feature of qualitative light planning. Even though areas with elevated ­brightness draw our attention and can help create an ambiance rich in contrast, luminances that are too high or luminance differences that are too great can severely diminish the perception. Various terms are commonly used to distinguish between glare situations and the way they work. Thus, occurrences of glare are differentiated first according to the way they originate, that is, whether the disruptive ray of light strikes the eye directly or indirectly via a reflecting surface: Direct glare is caused by the light source itself; for example, the sun or a bright part of the sky. The angle of glare is crucial, that is, the angle whose vertex is defined by the eye and whose sides ­extend to the visual task and the source of glare. This type of glare can be reduced naturally and most easily when light sources (i.e., window openings) are arranged to lie as far as possible from the most frequent line of vision. Glare by reflection, on the other hand, originates indirectly from the reflection of the light source on shiny surfaces. The bestknown examples of this are reflections as they occur on bodies of water, glasses, veneers, polishes, but also on glossy paper or on monitors. Glare by reflection can be diminished by reducing the illuminances shining on surfaces or appropriately distributing brightness with light sources that cover large areas and radiate light diffusely. A second distinction is also frequently made: between disability glare and discomfort glare. While disability glare is caused by very high luminances of an area in the visual field and leads to an actual decrease of vision, discomfort glare is when vision is ­negatively affected by unfavorable—excessive—luminance contrasts in the field of vision: such glare is annoying without actually causing eye strain. Disability Glare from Excessive Luminances Disability glare arises when an unscreened light source is located in the visual field, for example, a window area that is too bright. ­Especially in the case of larger windows, vision can sometimes be significantly impaired because the user’s eyes have to adapt to zones of varying brightness within the visual field. One of the largest sources for the occurrence of disability glare is the sun. While it is true that in residential construction the line of vision is seldom fixed, the radiation of sunlight into day rooms or workspaces can be a nuisance and, along with glare, become an issue. As, for ­example, in the course of building with the sun, where an extensive glazing of the south facade is meant to ensure that the rays of the low winter sun penetrate far into the rooms and thus help to warm the building. But even in the case of east, and especially west, ­facades there is considerable risk of glare, which is why good sun shading must be supplemented by other antiglare measures on such facades. In contrast to sun protection—for which a rigid con­­ struction on the exterior facade proves sufficient in certain ­cases— ­antiglare devices should without question be individually

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All-glass facades can produce effects that diminish perception (such as glare re­­­sulting from excessive luminance within the field of vision) and reduce visual comfort.

adjustable, which is why it always makes sense to supplement ­exterior sun shading measures with at least one interior antiglare device, such as venetian blinds. It is interesting in this connection that the disturbance effect in situations of direct solar radiation, on account of its positive connotation, appears to be lower than in situations of artificial sources of glare and moreover is dependent on the size of the window. Studies have shown that the effect of glare is found to be less irritating when a window is small. With a medium window size, however, there is a large contrast between the source of glare and the surrounding area, which leads to a larger glare effect. With wall-size windows, on the other hand, the contrast to surrounding areas remains comparatively weak because the adaptive powers of the eye reduce the effect of glare. All in all, it can thus be said that the limit of tolerance in cases of glare through sunlight are then probably highest if glazing constitutes around 40–55% of the wall area.27 Glare resulting from luminance that is too high can even occur via a look through the window at the diffuse sky. Thus, the sky visible from the interior can also be an omnipresent source of glare, and it may still have a very high self-luminance value even when it is cloudy. Even the reflecting wall areas of neighboring buildings can display high luminosity, provided they are illumi­ nated by the sun. It goes without saying that the first and most effective measure for the prevention of disability glare has to be the elimination of the glare light source from the viewer’s direct visual field. In the end, the observer’s angle of view to the light source is one of the decisive quantities causing direct glare. Thus, if the desire is to supply light to a room via one single window, the opening should be mounted at least as far above eye level as possible and towards the north side. The problems of glare can actually only be defused, however, when one ensures that the view onto open sky or other potential sources of glare, like highly reflecting exterior surfaces (including snow and water surfaces) is reduced to a minimum. Aside from vertical blinds or curtains, the use of a shielding construction element can remedy the situation, be it the mounting of an exterior mobile antiglare device or of a screen. 166

Luis Barragán, Barragán House and Studio, Tacubaya, Mexico City, 1947–48. Living room.—A room separated by two partition walls as an example of a solution achieved by the simplest means of planning that not only reduces a potential source of disturbing light but also contributes to the ­atmosphere in the room.

Shielding via a screen. An inspiring example of the use of such a screen is provided by Luis Barragán’s studio, where the archi­ tect largely shielded a big, bright window by means of a low ­partition erected after the fact, thereby banishing the disruptive brightness from the visual field. The partitioned-off area between living room and library becomes a place that fosters concentration and serves as a workspace. The somewhat unorthodox solution for the position of an oriel illustrates, moreover, that potential glare problems can also be countered by resourcefulness: in this case, in lieu of a fully glazed bay window area, the front side was boarded up, so that the room primarily receives daylight that enters indirectly—and ­without risk of glare. Geometry of the room or building. An additional option for avoiding high luminances in the visual field lies in the designing of a suitable room geometry, or rather, in the hidden construction of a window opening. Here again Luis Barragán provides our example: in this instance he avails himself of an L-shaped floor plan and adds a slight bulge with a window facing the courtyard. In this way he uses the recess position for lateral lighting of the long room space while the light source itself remains hidden from the observer’s view.

Classic and unorthodox solution: Oriel with windows (kadawittfeldarchitektur, ­St. Nikolaus residential building for seniors, Neumarkt am Wallersee, Salzburg, 1999–2001). Oriel closed in front ­(Armin Kathan, Martin Schranz, and Erich Strolz, Residential building, Höttinger Au, Innsbruck, 1995–96).

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Luis Barragán, Barragán House and Studio, Tacubaya, Mexico City, 1947–48. Study next to the studio.—The L-shaped floor plan creates a nichelike bulge that is used for side lighting. Hence the light source is hidden from the viewer.

Discomfort Glare from Excessive Luminance Contrast Discomfort glare is when vision is obstructed as a result of excessive luminance contrast in the visual field. This happens when strongly differing luminances occur right next to each other. Thus, an inside wall with windows, for instance, appears darkest to us precisely around the window’s edge. Another example of discomfort glare can occur by glancing down at one’s desk, when a white piece of paper appears against a dark background. Although in these cases vision largely remains intact, when the effect is ­prolonged discomfort glare leads to signs of fatigue and reduced performance. If optical working conditions are to be kept ergonomically stable, low-contrast luminance ratios have to be created in the space. A fine-tuning between the object to be judged and its surroundings is essential for this. As already explained in connection with the quantitative targets, the starting point for a specific plan for lighting for the workplace is a fixed visual task that determines the so-called close range. With the help of the visual task, a coordination with the sur­ rounding spatial surfaces and, along with this, a division of the ­visual environment take place. Accordingly, the concepts inner field and outer field distinguish between two different optical fields of perception that exist in a mutual dialogue with one another. 28 Stable, that is, glare-free, perception is only ensured from the ergonomic point of view when the contrast between the luminances of the near field of vision (inner field) and those of the more distant surroundings (outer field) occur in a tried-and-tested ratio: the maximum contrast between visual task and immediate environment should not be greater than 1 : 3, and between visual task and distant environment, not greater than 1 : 10.29 In view of the fact that adherence to this value is rather illusory in reality, we wish at this point to refer the reader to an advanced English publication that has established that the ratio between light source and surround-

Le Corbusier, Cabanon Le Corbusier, ­Roquebrune-Cap Martin, Côte d’Azur, 1951–52.

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3: 1

1 : 10

1 : 10

Luminance relationships: Acceptable ­contrasts in surface brightness according to Étienne Grandjean.

ings should be no more than 20 :1; in any case, however, it continues, a maximum contrast of luminances in interior space must not exceed the ratio of 40 :1.30 That is the theory. Beveling the reveal. To return once more to the concrete ­example of the window, however, whose bright area forms a strong contrast with the dark wall in cases of exposure to light that is only on one side in a room: a simple planning option to counteract this large contrast is the construction of a deep reveal beveled to the plane surface of the window. This creates a zone of medium brightness that reduces or entirely eliminates the glare effect. Otherwise the principle of remedying visual impairments from excessive luminance differences is the same as that already explained in the section “Reducing Contrast.” As was noted there, con­ trast can be reduced by increasing the overall level of exposure to light or through shading which in turn functions by increasing the amount of diffusion in the space. As a reminder: Slits rather than holes. If openings are arranged on the edge or in the corner of a room instead of in the middle of the wall, the light streaming in floods the areas of the wall perpendicularly adjoin­­ ing the window wall. The illuminated surface itself then becomes a light source and increases the diffuse illumination of the room. Light from two sides. One of the most effective ways to avoid ­dis­proportionate brightness differences between neighboring zones in a room is by adding a second window. This second window, ­pre­ferably placed in the wall adjoining at a right angle, raises the ­overall level of exposure to light in the space. The light of the one side, moreover, illuminates the other side in each case and thus ­decreases the contrast between the walls and the bright window ­areas. Diffusion. In the end, light refractors on the outside, mounted over an opening, can also have a shadowing effect and contribute to reducing the luminance of the window area.

Johannes Kaufmann, PAVI House, Bad Waltersdorf, Steiermark, 2001–2. Living room.—Beveled reveals reduce glare from excessive luminance contrasts around ­window edges.

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Silhouette Effect In this context we also wish to emphasize the so-called silhouette effect that occurs in rooms with exposure to light on one side only. If a person or an object stands or is placed before the window it is only their silhouette that can be perceived. The problem is that the subject is illuminated from behind causing the emergence of a darkening self-shadow on the unlit side turned toward the viewer. This shrouds form and texture in a diffuse shadowiness, which, on the one hand, undermines the modeling, and on the ­other hand, sets up a strong contrast to the bright window area in the background. This is especially unpleasant when faces are ­involved. The shadowing of the eyes and nose of the person standing opposite as well as glare caused by back lighting can negatively influence communication. To counteract such a situation—provided that exposure to light on two sides is not possible—the indirect radiation of light has to be reinforced, meaning that part of a room’s lighting that comes from inside reflections. Accordingly, this vertical light is especially effective in the back of the room but turns out to be considerably weaker in comparison to horizontal illuminances. The latter are, of course, found mainly near the window. Here direct light from the sky, from the brighter regions near the zenith, dominates the room’s lighting, which is why the radiation of the horizontal ­areas in this zone is particularly strong. This also explains why the silhouette effect is much stronger especially with people and ­ objects directly in front of the window than with positions located deeper within the room.

The so-called silhouette effect results when the luminance of the background is much greater than that of the object ­observed.

Solar Control and Directing Sunlight Solar radiation not only interferes with visual comfort through occurrences of glare that can arise but also makes a significant dif­ ference with its high thermal load. This latent risk of overheating makes good solar control indispensable. At the same time, a ­suitable building form and optimized shading measures can greatly influence a comfortable spatial environment. For this reason, ­familiarity with the different solar radiation various facade orientations offer is absolutely essential. While the sun’s path in our ­latitudes only extends from south–east to south–west in the winter, it is longer in the summer: from north–east to north–west. Moreover, because of the sun’s changing position, the intensity of solar radiation on parts of buildings also varies according to the time of year. Sun protection that functions well has to take these aspects into account. Consequently, windows are to be treated differently according to their orientation. While this used to be done via ­ so-called shading diagrams calculated in drawings, computer programs do this work today. These allow, almost instantly, the representation of the shadow cast for each room and every window at all times of day and in all seasons. North-facing windows produce a very constant incidence of light and minimal heat gains. In the heating period, however, there is also the risk of heat losses and the associated losses of comfort. Here solar control measures are necessary only for early morning and late afternoon hours. South-facing windows admit generally high illuminances in a room, but these can vary significantly in the course of the day.

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Solar control measures can usually be implemented relatively ­easily, that is, without complication and effectively. East-facing and west-facing windows, by contrast, prove to be somewhat problematic with respect to the implementation of ­effective solar control measures. Equivalent steps are to be taken on both sides, and major heat gains, particularly in the west, are to be expected. For this reason, too, extensive glazing should ideally be avoided here. Today there are a multitude of possibilities with regard to the ­arranging of solar control that can be summarized by a few typical facade variations. To that end, a distinction between singleand multiple-skin facades will be made in what follows below. Single-Skin Facades In the case of single-skin facades, which consist merely of the ­glazing skin and additional solar control, it is a matter of differen­ tiating between exterior or interior measures or between solutions that are themselves integrated into the window skin. Exterior sun protection proves to be the most favorable from the thermotechnical point of view: it achieves a higher efficiency than interior sun shading because the heat arising through the absorption of sunlight remains outside the building, so exposed to weather factors. Ultimately, exterior sun shading also has to be further ­subdivided into fixed or mobile constructions that come with different maintenance costs.

Flat roof in summer

Sunlight intensity (W/m2 )

South wall in winter West wall in summer

East wall in summer South wall in summer

East wall in winter

Global radiation in summer

West wall in winter

Global radiation in winter

Time of day (h)

The duration and direction of the sunlight entering according to the season and time of day determines the installation and position of the solar control. In the summer, west and east facades get more light than southern facades; in spring and ­autumn the reverse is true. North–south ­orientations are thus more problematic where solar control is concerned.

Summer

Winter

Time

Angle

Intensity

Orientation

in the morning

low

medium

East facade

at midday

high

strong (esp. roof)

South wall, little radiation

in the evening

low

intense

West facade

low, since brief

East facade

intense and long

South facade

low, since brief

West facade

in the morning at midday in the evening

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low

Fixed sun shading devices are found mainly in the form of roof projections, balconies, overhanging parts of buildings, brises-soleil, or also permanently mounted slats. In most cases they ­become ­distinctive elements of the facade design and are essential features of a building’s overall architectural expression. Projecting roofs. In connection with energy-conscious con­ struction, projecting roofs are gaining in importance once again. Con­ ­­tingent upon the varying angle of incidence of the sun’s rays at different times of year, a projecting roof can keep the sun out of interior spaces in the summer and let it in as a provider of heat in the winter. Brises-soleil or fixed slats. Brises-soleil are fixed slat structures that are superimposed on the facade thus preventing a direct penetra­ tion of the sun’s rays. In the case of south-facing windows, for instance, small horizontal projections can ensure that, in the summer, when the position of the sun is high, direct solar radiation of the openings does not take place. For windows on the east and west facades, by contrast, vertical shading elements are considered ideal, for they not only block the solar radiation but also reflect part of the light into the room. Steel grates can be used in the same way, in which case their alignment and spacing are to be selected as a function of period of time when the sun shading should be in effect. While the advantage of such installations lies very generally in an undisturbed view from interior to exterior space, and while ­questions regarding material and wind exposure are also not of con­ sequence, fixed sun-shading measures prove to be inadequate ­insofar as they cannot react to the daytime and seasonal variations of the sun’s path. Moreover, it is to be noted that a permanently mounted horizontal sun-shading device always shields the zenithal sky component, which, because it is the brightest, is the most ­essential for the lighting of the room.

Le Corbusier, Textile factory Claude et ­Duval, Saint-Dié-des-Vosges, 1946–50. ­Facade with projecting brise-soleil grid.— Beginning in the 1930s, Le Corbusier added a new element to the instruments avail­ able to modern architecture by “inventing” the brise-soleil: a frame for sun protection fixed in front of the facade as a very ­inexpensive, low-maintenance, and longlasting solution, especially for southeast and southwest facades.

Adjustable systems, however, offer more effective sun shading than fixed constructions because they can be adjusted to the different weather and seasonal conditions—but more maintenance costs are also associated with these systems. Adjustable sun shading ­measures include the classic folding shutter, roller shutters, slat blinds and awnings, sun sails, fabric and grille materials as well as ad­ justable facade elements like panels and gratings. Awnings and slat blinds. Awnings are simple and effective: they cut out sunlight by ensuring a cast shadow in front of the window from outside. They do an excellent job of keeping heat out of the room, while still allowing the room to appear very bright. The view out is also completely preserved, at least at the lower part of the window. Overall, awnings integrate well into architecture; however, they are very susceptible to wind and are rather unsuited as antiglare devices. By contrast, blinds with adjustable horizontal slats placed before the facade enable an exact controlling of light. Sunlight can be completely cut out or directed toward the ceiling to be used in the back of the room. In contrast to conventional awnings and blinds, venetian blinds do afford a certain ­protection against glare, though in exchange the view from the win­ dow is restricted. In addition, external blinds are also susceptible to wind.

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Flora Steiger-Crawford and Rudolf Steiger with Peter and Martin Steiger, Steiger House, Bergstrasse 67, Zurich, 1959.—Projecting roof surfaces used for sun shading and as an essential element of the architectural expression.

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Drop-arm awning on a residential building in Zurich. KGP Kyncl Architekten, Puls 5 residential and commercial complex, Zurich-West, 2001–4. Facade with sliding shutters.

Adjustable facade elements. Light-permeable gratings hung before the facade, metal or wooden folding shutters (as the archetype of all adjustable manipulators and frequently varied to this day), or sliding elements covered with nylon fabric that, depending on construction, are employable simultaneously as protection against sun and glare or protection of privacy—these all function as a ­moment of movement in the stasis of the building. These devices can be regulated as one likes and adjusted to different requirements for light and views. At the same time they are also expressive ele­ ments of the facade, providing information about the living ­conditions on the inside. Interior sun shading measures are generally less effective because heat as well as light enters the room and has to be diverted. ­Common systems are slat blinds, shades, screens, venetian blinds, and curtains. Textile materials. Textile materials present a reasonably priced option for sun shading; moreover, they are also easy to maintain and clean. They are especially suited as a supplement to an exterior construction, and as such are able to take over the antiglare function. If interior sun shading is the only feasible option, then light colors should without question be used in order to reflect solar heat to the outside. If exterior sun-shading devices are not possible for reasons of ­design, then self-shading can be achieved by means of a corresponding planning and organization of the building. In this case, options include the construction of building wings, balconies, arcades, or ­also the mounting of deep window reveals.

Christian Matt, Residential building, ­Bregenz, 2000–2003. View from outside, living room.—When it is necessary to ­­­ preserve the intended architectural char­ acter of a facade, or when external ­awnings are not possible, interior awnings are one solution. They do no, however, provide ­satisfactory protection against heat. Bright colors that reflect the radiation back ­outward achieve the best results.

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Solutions placed in the plane of the window itself, such as solar-control glass, whose coating filters out heat radiation in the infrared range, have been used since the 1970s. Just like light-directing glass systems that place light-reflecting surfaces in the space between double panes of glass, these solutions are, however, on account of their high cost, still not yet very widespread in residential construction. In the course of the great strides being made in glazing technologies, it is, however, to be expected that these products will soon become more affordable and innovations like electrographic ­shading effects and more besides will also find their way into this market segment. Double-Skin and Multiple-Skin Facades Another option is double-skin or multiple-skin facades in which an additional plane is arranged before the actual conclusion of the room. Although such facades are more complicated technically and more expensive than conventional shells, they do boast very good advantages with regard to energy management and the control of sunlight or daylight. Multiple layers. In double-skin or multiple-skin facades, a second glazing is arranged before the actual shell of the building. This results in a between space that can be connected either with the indoor air or with the outdoor air. Sun shading is laced in this gap. Such solutions are particularly suitable for buildings that are to be ventilated naturally but because of their locations or heights have considerable exposure to noise or onslaughts of wind. Spatialization of the facade. A spatialization of the facade creates buffer or transition zones that mediate between light and dark and thus afford a better sun and glare control (contrast glare).

Overall, constructive solar control thus means more than just a pure “defense against light”; it is not just to protect against overheating but is also to produce an individual, tailored-to-need, and solution-oriented form of expression.

Georg W. Reinberg and Peter Thalbauer, Residential building (Section 4), Thürnlhof­ strasse, Vienna-Simmering, 2005–6. ­Loggia.—The second window demarcates a private outdoor area.

Daylight as Design Medium To date the illumination of the workplace has remained the real main area of all construction-relevant considerations for daylight planning. Only all too often this seems to be limited to the fulfillment of a stipulated minimum level of illuminance or of a determined ­daylight factor—magnitudes that in reality say little about the actually perceived brightness in a room. Sufficient emphasis on qual­ itative (let alone design) objectives of light planning (especially as far as residential construction is concerned) is just as rare in the ­relevant literature, although adherence to these objectives is just as essential for the visual conditions in the interior as the existing quantitative demands. The main criterion for perception-oriented light planning cannot, however, be the readout from a measuring instrument but rather has to be the human being and the manner in which illumination meets his visual demands. Although the awareness of just a few basic facts and connections is enough to comply with the demand for a deliberate lighting design, the knowledge of simple but calculated manipulations of light effects is often not very developed among architects. Many still think they have solved lighting problems at the design stage

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BEHF Architekten, Residential building, Kollmayergasse, Vienna-Margareten, 2002–4. Transition to the terrace.—The spatialization of the facade creates buffer and transitional zones.

with the mounting of enough window area. Sometimes the focus on lighting concerns is even seen more as a tiresome duty than as a ­creative and design-related challenge: wherever there are hard-andfast specifications to be met, they prefer to leave it to professional light planners or engineers. In most cases these light planners and engineers have to play the part of follow-up assistant forced to build on the architect’s guidelines. Such a separation often proves fatal, for lighting design cannot be supplied at a later date but can only be conceived in parallel to the building plan. Even the most costly daylight systems are useless when fundamental mistakes are made during architectural planning, such as for instance, unfortunate room and window dimensions, the choice of “wrong” ­materials, or even possible self-shading through projecting parts of the building or structure. For this reason, a lighting plan is called for that, as an integral part of the overall architectural design, ensures a visual environment that supports people not only while doing their jobs and in their demands for a comfortable, stimulating spatial environment, but also makes allowances for their aesthetic needs and at the same time is concerned about and attuned to the effect of architecture. Only sufficient knowledge of the process of seeing and of the con­ struction of visual impressions combined with the corresponding design competence can lead to truly satisfying solutions.

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1 This categorization is based on a distinction that Gerhard Auer makes in his ­t heoretical writings on light (see also his contribution in the present volume). 2 With an overcast sky, the utilization of daylight falling through a skylight onto a (horizontal) surface is two to three times greater than lighting from the side. 3 The darkest areas are those at a 90° angle to the sun. 4 The percentage of visible sky can be calculated as follows: a straight line is drawn upward from one reference point in the window; another straight line is drawn from the reference point to the upper edge of the other building. The angle between the two lines describes the percentage of visible sky. The effect that other buildings can have on electricity consumption is astonishingly high: for example, if 30° of the visual field are built up, energy consumption will increase by 38%; see Nick Baker and Koen Steemers, Daylight Design of Buildings (London: James & James, 2002), 46. 5 The share of skylight refers to conditions with a diffuse sky (scattering by ­overcast sky). 6 The minimum requirements are recorded as quantitative and qualitative signs of quality. DIN 5035 defines the quality of illumination by the following criteria: lighting level, brightness distribution, glare restriction, light direction and shadow, color of the light, and color reproduction (although the last of these is not relevant to planning for natural light). 7 If there is no primary light from the sky, however, reflection alone will bring hardly any light into the rooms; see Udo Dietrich, “Daylight: Characteristics and Basic Design Principles,” in Detail Practice: Lighting Design; Principles, Implementation, Case Studies (Munich: Edition Detail, 2006), 16–41, here 23. 8 Recommendations for the reflectance p of ceilings, walls, floors, and furniture: ceiling: > 80%; walls: > 50–70% (if the wall is to have a window, these figures should be even higher); floor: 20–40%; furniture: 25–45%. In general matte surfaces are preferable to glossy ones as they provide better illuminance distribution. 9 The formula for uniformity of illuminance distribution in an interior DF min / DF max < 1: 6 refers to side lighting. If the light is from a skylight, the ratio should be < 1: 2. Note: illuminance distribution (= uniformity of lighting) refers to the ­ ratio of DFs to each other and should not be confused with distribution of brightness which describes differences in luminance and whose ratios should not exceed 1:10 and 1:3, respectively. 10 Other crucial factors are the size of the object and the eye’s state of adjustment (this is one reason why, if the eye has not adjusted to bad lighting conditions, even very large black type on a white background cannot be read). 11 Whereas for office spaces in general, an average DF of 3–5% are called for (or at least a minimum of 1–2.5%), recommendations for residential buildings generally call for a DF of 1.5% and a minimum of 0.5%. For kitchens, by contrast, a DF of 2% and a minimum of 0.6% should be assumed; data from Baker and Steemers, Daylight Design of Buildings (note 4), 61. 12 To ensure uniform lighting of the entire area, according to the 30° rule, the ­d istance between skylights should not exceed the ceiling height. 13 For residential buildings, an average DF of 1.5% is considered sufficient. Places in the room that fall below the minimum of 0.5% are considered too dark. Usually this applies to places 4 or more meters deep (and even then this value is only reached when the window is placed high in the wall). 14 Christian Bartenbach to the authors, December 10, 2003. 15 Le Corbusier and Pierre Jeanneret, “Five Points toward a New Architecture,” trans. Michael Bullock, in Ulrich Conrads, ed., Programs and Manifestos on ­Twentieth-Century Architecture, trans. Michael Bullock (Cambridge, MA: MIT Press, 1970), 99–101, here 100. 16 See Baker and Steemers, Daylight Design of Buildings (note 4), 66. 17 The most important factor occupants use to judge the size of a window is width rather than height. Studies have shown that the transparent part of the window or the sum of the width of all windows should be at least 55% of the width of the room. Moreover, the height of the transparent part of the window should not exceed 1.3 meters; see Michael Seidl, “Tageslicht in Innenräumen,” in Johannes Beckert, ­Fridolin P. Mechel, and Heinz-Otto Lamprecht, eds., Gesundes Wohnen: Wechselbeziehungen zwischen Mensch und gebauter Umwelt; Ein Kompendium (Düsseldorf: Beton, 1986), 206–16. 18 See Mike P. Wilson and Luisa Brotas, “Daylight and Domestic Buildings,” http://www.learn.londonmet.ac.uk/about/doc/brotas_bulgaria2001.pdf, p. 29 ­(accessed May 10, 2008). 19 The ceiling should not only have the highest reflectance possible, over 80%, but should also be free of beams, suspended parts, and the like. 20 Christian Bartenbach to the authors, December 10, 2003.

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21 So-called Dreispänner (buildings with three units per floor) should thus be avoided, as at least one apartment will get light from only one side. 22 See “Strategies for Fenestration,” sec. 2.2.4 of IEA Task 21. Daylight in Buildings. Source Book, http://www.iea-shc.org/task21/source/daylighting-c2.pdf ­(accessed May 10, 2008). 23 Glazed atriums have a negative effect on the illuminance distribution of natural light in adjacent rooms: the high angle of build-up eliminates much of the vertical component, which is particularly noticeable in the depths of the room (hence the need to respect a minimum ratio of width to height of 2 :3). 24 Courtyards benefit especially from light reflected from the ground. They can provide one to two times more daylight than covered atriums. When the sun is ­shining and highly reflective materials are used, there is, however, a risk of glare. 25 Opaque, brightly painted surfaces are beneficial since they are much more reflective than transparent materials. Glass, for example, has a reflectance of just 15%; see Baker and Steemers, Daylight Design of Buildings (note 4), 49. 26 The following parameters of the atrium all influence the DF in the interior: ratio of height to diameter of the courtyard, transmittance of roof glass, average reflectivity of walls, average reflectivity of floor, size of windowpanes in interior, reflectivity of interior walls, ceiling, and floor. 27 Tariq Muneer et al., Windows in Buildings: Thermal, Acoustic, Visual and Solar Performance (Oxford: Oxford Architectural Press, 2000), 112. 28 Inner field refers to the visual field of the eyes in the area defined by the latitude of the eye’s movement. This area taken in by both eyes together extends to about a 90° angle and thus includes the fixed field of the (static) gaze. Outer field refers to the visual field of the head, which includes the peripheral part of the visual field and the field of vision. This contributes to the overall impression of the lighting conditions in the room and thus includes that part of the visual field and field of vision with which the broader surroundings are taken in. 29 Friedrich Sick, Einfluss elementarer architektonischer Massnahmen auf die ­Tageslichtqualität in Innenräumen, diss., Technische Hochschule Universität Karls­ ruhe (Stuttgart: Fraunhofer IRB, 2003), 15: “Only medium luminances were ­considered; the nearer surrounding field is concentric around the main direct of viewing with an angle of opening of 30°; the distant surrounding field has twice that opening”; Volkher Schultz, Projekt Tageslicht: Licht und Architektur, http://www. fvlr.de/downloads/Lichtarch1.pdf, p. A54 (accessed May 10, 2008): “In practice, ­simple rules are used to calculate luminance ratios when designing workplaces: inner field to near surrounding field to distant surrounding field = 10 :3 :1 to 0.1.” 30 Figures from Benjamin H. Evans, Daylight in Architecture (New York: ­McGraw-Hill, 1981), 2.14.

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Lighting Effects: Beyond Seeing ­Comfortably Well-Being, Mood, Experience

The Consequences of Flooding with Light Modernism’s schema of polarity, in which the world was divided into pairs of concepts such as good–bad, bright–dark, light–heavy, or transparent–secret, still influences our thinking today. For ex­ ample, it is evident that what today’s residential architecture often lacks is subtle intermediate tones and shadings. Technical possi­ bilities make it easier to take plans right off the drawing board that disregard geographical and culturally determined partic­ularities. Often, this results in buildings whose commodity character is mani­ fested in facades that lack content or imagination. The trend for ­interiors still seems to obey the Olympian commandments: bring more and more brightness into greater depths. ­Sometimes the ­interior extends so far out to meet the exterior that they cease to be opposites that could be reconciled by light. Then it is not just ­uniform lighting that is wearying but also the loss of tension and the impoverishment of the sense of space that result from an almost ­unlimited use of glass surfaces. And so it hap­pens that an uneasiness creeps over some of us when glass is used to obliterate the external wall, since what is left usually seems anything but homey.

Luis Barragán, Prieto López House, ­Jardines del Pedregal, Mexico City, 1950. Living room. Hasler Schlatter Partner Architekten, Steinacker housing development, ZurichWitikon, 2002–4.—The trend toward the glass standard box has long since reached mass housing construction as well.

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If inadequacies of planning are evident today in many respects, they lie not in superficial lighting deficiencies but rather in a general ignorance of the design possibilities of light and its im­ plications for architectural space. Light is more than just an aid to perception: light makes it possible to modify the appearance of spaces without changing them physically. Light can seem to expand or contract spaces, create connections, or demarcate areas from one another. It can, however, also evoke memories, create associa­ tions, and trigger moods. The following chapter, therefore, will treat light’s value as an element in the design and—insofar as it can be planned at all—experience of architecture. It is about the light that goes beyond being an aid to seeing and affects the appearance of the space as a means of aesthetic and atmospheric design. A Loss of Homeyness? Homeyness under the sign of transparency is a development that was met with skepticism from the time when it was first advocated. For example, in a brief satire of the transformation of architectural style, Joseph Roth reflected on the omnipresent “modernization trends” in Berlin in the 1920s:

Domestic interior design is a fraught affair. It makes me hanker for the mild and soothing and tasteless red-velvet interiors in which people lived so undiscriminatingly no more than twenty years ago. It was unhygienic, dark, cool, probably stuffed full of dan­ gerous bacteria, and pleasant. The amassing of small, useless, fragile, cheap, but tenderly bred knickknacks on the fireplaces and side­ boards produced an agreeable contempt that made one feel at home right away. Countering all the tormenting demands of health, ­windows were kept closed, no noise came up from the street to inter­ rupt the useless and sentimental family conversations. Soft carpets, harboring innumerable dangerous diseases, made life seem livable and even sickness bearable, and in the evenings the vulgar chandeliers spread a gentle, cheerful light that was like a form of happiness. The lives of our fathers’ generation were lived in such poor taste. But their children and grandchildren live in strenuously brac­ ing conditions. Not even nature itself affords as much light and air as some of the new dwellings. For a bedroom there is a glasswalled studio. They dine in gyms. Rooms you would have sworn were tennis courts serve them as libraries and music rooms. Water whooshes in thousands of pipes. They do Swedish exercises in vast aquariums. They relax after meals on white operating tables. And in the evening concealed fluorescent tubes light the room so evenly that it is no longer illuminated, it is a pool of ­luminosity.1 Roth names the things that he believes are responsible for the effect of coldness in residential buildings: where harsh lighting, naked architectural truths, and sprawling spaces ensure that the functional body is exposed and laid bare, while the warmhearted and any quality that could inspire one to take possession of it fall by the wayside. The elimination of all darkness and blurriness, of blind spots and undetermined zones in the home stifles the imagination. 182

A “comfy” living room: An atmosphere of intimate, familiar seclusion, enhanced by personal souvenirs and all sorts of ­accessories. Bulant & Wailzer, Glass garden room, ­Vienna-Hietzing, 2002.—Indoors like outdoors? Today rooms are being built whose brightness approaches that of the outdoors yet are still interiors in terms of being protected from wind and weather. The more light that enters, the more the inte­rior loses the specific effect of some­ thing inside.

The guiding principle for architecture today is still partly trapped in the modernist way of thinking that focused on the human being as a rational being and ignored everything that was inscribed by evolution in the natural history of human beings. Cap­ sules of transparency with open rooms, doubled heights, and views through and into the building may be a widespread architec­ tural standard today to which an intellectual (and affluent) audi­ ence feels obligated. The majority of the population, however, turns out to be astonishingly resistant to such figments of the imag­ ination, even after eighty years of propaganda work and education on the culture of living, and clings instead to the deeply rooted ­­ desire for a warm nest and the power of the shell to conceal. Housing is subject to extremely conservative basic patterns, as empirical studies have repeatedly shown. In addition to the ­connection to nature and the outdoors, one of the criteria that reg­ ularly ranks highest in housing surveys is maximum intimacy, ­protection from people looking in or seclusion from neighbors—an ancient concern in housing. Hence even the occupants of the upper floors of high-rises are concerned about covering large win­ dows in their apartments so no one can look in—reason enough to assume that people have an inherent psychological tendency to isolate and secure their private sphere at times. By contrast, as part of the intensified lifting of taboos in society and the disappearance of a general consciousness for the meaning and value of traditional boundaries between the public and the private, such legitimate needs for withdrawal and distance (and the possibilities for realizing them architecturally) have increasingly come into focus. Hence the ambition of many architects to dissolve spatial boundaries is often strangely detached from reflection on the later reality of use. In addition to the loss of a private sphere, the placement of windows in a home is usually not without consequences for the furnishings. The latter can be very re­stricted by the dimensions and position of windows: where to put the cabinets and bookcases if the open plan offers all kinds of ­ exciting prospects outward but not enough places on which to put things? 183

The limitation of architectural means and forms imposed on us by modernism was originally intended to create an emancipatory atmosphere: a backdrop against whose white and transparent walls the activities of the occupants freed of compulsions and con­ ventions could emerge all the more clearly. Today, however, there are many faceless and soulless buildings going up all over the place whose external conditions are in fact far too narrow for those dwelling inside them. From a psychological perspective, housing entails a close inter­ action of people and their environment, since, on the one hand, the housing environment influences the people and, on the other, the occupants can also shape that environment themselves. In the ­process, the latitudes for action—that is to say, the opportunities to design and personalize the space oneself—are of central impor­ tance. It is obvious that a living space should be functionally and aesthetically pleasing, but that alone is not enough to satisfy its ­occupants: “For a dwelling to be transformed into a house, the user must be able to develop links with it and adapt it to himself.”2 This presupposes, of course, that the architectural form has no life of its own or only a limited one and hence should not be “over­ conceptualized” put rather imperfect and open enough for the ob­ stinacy of subjective appropriation. The culture of a dwelling emerges from the self-determination of the occupants—hence the architect has to allow the traces of use. Furthermore, it should be recalled that in assessing homes there is often a considerable discrepancy between the architects’ per­ spective and that of the users. Usually the reduced design that is precisely the appeal of a project for architects cannot be grasped by laypeople. Whereas architects have a rich storehouse of experiences that provides them with a frame of reference, laypeople per­ ceive the building primarily in terms of its material reality, whereby concrete and glass—which move away from the traditional schema for a house and its connotation of warmth and security— are often seen as “cold.”3 A home is habitable when it is pleasant to live in it. As simple as that may seem, it is seldom the case with most of the homes pre­ sented as exemplary in glossy magazines. It is symptomatic that there are never people in the rooms exhibited therein. Residential archi­ tecture, however, has to meet criteria that differ from those for a bank or a museum. If the standard for the latter may be extravagance or originality, the reality of residential architecture calls for the normal, the appropriate, the matter-of-fact—that is, for small qualities ­rather than large gestures. It is more about permanence and taking into account obviously stable basic patterns than about inno­vation at any price. Architects cannot just be designers; they have to see themselves as scouts and moderators between the culture of ­living and the culture of building. Achieving the necessary trans­­la­ tion between the expert view and the lay view depends on them. 184

Rudolph M. Schindler, Oliver House, Los Angeles, CA, 1933–34. Living room.— “The cave offered primitive man a feeling of security thanks to its seclusion and ­enclosure. ... Rooms that invoke these feel­ ings of security by means of formal echoes are commonly called ‘comfy’ or ‘cozy,’” wrote Rudolph M. Schindler. Residential building is more about the normal than the extravagant, more about small qualities than large gestures; it is about attentive­ ness and variety. Patrick Gartmann, Gartmann House, Chur, 2003. Living room with view of Chur.— ­E xposed concrete walls and manifestly ­ gaping openings may seem beautiful and correct to the trained eye, but that does not give one the right to generalize one’s own taste.

Josef Frank and Oskar Wlach, Beer House, Vienna-Hietzing, 1929–30. Seat by the window in the living room.—The large window leads into the environment, but the wall beneath it also emphasizes the boundary between inside and outside and contributes to a protective atmosphere in the room.

Physiological and Psychological Comfort The coziness of the good old days is a platitude—though one that should stimulate us to think. How does architecture become a place in which people can feel at home? What is actually perceived as comfortable? Historically, comfort has had many cultural connections to the concepts of coziness and convenience. The modern concept of ­comfort emerged in the nineteenth century as part of the European reception of the English country home. Although it was originally associated with ideas of an informal private sphere, from the 1880s onward, comfort turned into a slogan to characterize the intimate form of individual rooms or a layout of rooms intended to reduce their spaciousness. At the same time, comfort was closely associated with all the things that contribute to physical well-being in the living environment. Over the course of time, the concept of comfort—which should always be seen in close connection with social developments— not only underwent a change in meaning but also an extension of its meaning. For example, in the social studies and humanities since the 1960s, the psychological states of people in their homes have moved to the foreground and hence too the usually irrational ­influential factors that appear to constitute the feeling of well-being at home. It is as if a distinction is now made between physiological and psychological comfort. With regard to physiological comfort, two potential adverse ­affects are particularly relevant to the theme of daylight. First, there is glare, whose disturbing effect on visual comfort was discussed in detail above. The other aspect that cannot go unmentioned in the context of the use of large glass surfaces is thermal comfort. For example, the relationship of ambient air temperature to the sur­ face temperature of the parts of the building is a crucial influence on physiological well-being. Thermal comfort means the body’s equilibrium of warmth is balanced—that is, we perceive the climate as pleasant and comfortable—when there is no radiation loss and a pleasant, regular surface temperature predominates. Conse­ quently, the materials used in a room play an essential role in ­thermal comfort in relation to their surface temperature. For exam­ ple, wood is perceived as comfortable while glass, a good conductor of warmth, is perceived as cool. One reason that the favored place by the window often becomes the coldest and least com­ fortable in winter is that the lower surface temperature of glass causes cold air to descend near the window. That happens when the heated ambient temperature is much higher than the surface ­temperature of the window’s glass. Then the air near the window cools and sinks to the floor, which can lead to turbulence that is perceived as an unpleasant draft. On the psychological level, it is primarily associations with pro­ tection, safety, and security that produce a feeling of comfort. This imprecisely defined field is just as important for human wellbeing as the satisfaction of the physiological conditions. Human beings have sought hiding places and security since time imme­ morial. The origin of all experience with interiors is associated with flight and defense. A room serves as refuge from cold, dampness, and threats, and it offers warmth and security under adverse ­conditions. “Feeling protected” is the fundamental meaning of the

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term “comfort.”4 The German word for “comfort,” Behaglichkeit, contains the word Hag, or “hedge,” and hence refers to a piece of land surrounded by a hedge that promises safety vis-à-vis the out­ side; the German word for “security,” Geborgenheit, derives from the word bergen, “to shelter, conceal.” Taken together, the guid­ ing concepts for our ideas of housing mean above all one thing: safety. But if safety is the deeper main function of housing, knowl­ edge of primitive human fears should be a fundamental prerequisite for the activity of design. According to the philosopher Otto Friedrich Bollnow, who ­became famous in the 1960s for his book Mensch und Raum (Human being and space), a living space that is supposed to radiate comfort has to convey above all an impression of being closed off. The desire for coziness seems to emerge particularly when people thirst for calm, relaxation, and recreation. The German neoclassical architect Karl Friedrich Schinkel had earlier established a con­ nection between solid weightiness and an individual feeling of secu­ rity and well-being. He associated with “weight, in its simplest effect,” a maximum of “safety and sense of comfort.” The deeply in­ grained human need for protection and security, which is evidently closely related to the desire for calm and passivity, consequently conditions a space that does not “make one unsure” (something cozy does not make us unsure!) but rather radiates a certain measure of weight and sense of being earthbound and permits only limited views inward. That the Other has to remain outside, so as not to disturb the coziness, seems to be what Friedrich Achleitner means when he writes: “Coziness means obtaining a distance from ­everything alien.”5

Subdivision of space according to Fred ­Fischer, who ascribes to every field of the room, based on the orientation of the ­individual within it, a specific meaning or value.

Front wall Primary escape angle

Covering wall

Wailing Wall phenomenon

(Penalty angle)

Left escape angle field

Frontal wall passage field

Right escape angle field

Left wall passage field

Central space field

Right wall passage field

Left protection angle field

Dorsal wall passage field

Right protection angle field

(Exhibition place)

Primary protection angle (Overview angle)

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Secondary escape angle

Attacking wall

Secondary protection angle Rear wall

(Hiding place angle)

Louis I. Kahn, M. Weiss House, East ­Norriton Township, PA, 1947–50. Living room.—Sliding wood blinds within an ­architecturally fixed basic structure enables occupants to adjust openings themselves.

The greater the distance to the ground, the greater the need for security.

Sociologists presume that a person will feel comfortable in a room that is at least fifty percent enclosed—that is, one that is either closed on two sides or one with openings accounting for no more than half its four walls. Looking around at today’s architectural landscape, however, it is clear that many buildings tend to either one extreme or the other. The stone monstrosities of the neotraditionalists are contrasted with the illusion of a lack of substance and openness to light of the current renaissance of glass buildings. In the meanwhile even many multiple-story residences reflect the sometimes dubious trend toward windows the full height of the space. Like a feast for the eyes, it is supposed to provide the occupants (at least those who don’t suffer from vertigo) with unrestricted views. For many, this takes getting used to, especially on upper stories, and sometimes results in experiences that are by no means positive. Fear of heights is not a rare phenomenon. Feeling comfortable on the upper stories of a building does indeed require additional encasement, which is ­easiest to achieve with window sizes that decrease toward the top or higher windowsills. Edward Hopper’s painting Room in Brooklyn (1932) illustrates that a corner with a generous window requires small measures such as a windowsill or muntins to ensure a positive effect on the sense of security. Since the modern age, the codex of psychological and physical intimacy has no doubt been loosened somewhat, and it may be that— given that housing needs, like other consumer desires, develop in response to the object consumed—a certain habituation has taken place. In essence, however, personal well-being, the primitive ­feeling of comfort in a space, is always coupled with properly metedout openness and lighting. One’s Own Four Walls Before further investigating the question of specific qualities of space and light, it must be explained what makes a space a space in the first place. Architectural space is created by the act of demar­ cating a small unit. It is defined by its demarcation, though it should be equated not with that demarcation but rather with what is

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Edward Hopper, Room in Brooklyn, 1932. Oil on canvas, 74 x 86.4 cm. Museum of ­Fine Arts, Boston, The Hayden Collection.—The wall beneath the window, even though it is low, and the sub­ division of the window contribute to a ­feeling of security.

­ ithin it. When interiors are constructed, dark spaces result, which w can then be mitigated again with localized openings in the bound­ ing surfaces. The arrangement, size, and form of the openings struc­ ture the space, giving it direction. The larger they are, the more they are perceived as a lack of wall, and hence the space seems less closed off. Thus planning means drawing boundaries. At the same time, the wall—as the very embodiment of the principle of architectural articulation—is not only a form of protection but also marks off private space. Accordingly, it is important for a dwelling that the certainty of being protected be perceived both in reality and ­symbolically. These days, when increasing urban density is consid­ 189

ered one of the central challenges of urban planning, the question of the interaction of private and public is coming more sharply into focus again, particularly in relation to home building. It is the ­architect’s task to mediate between the individual needs of the user and the long-term interests of the public and to find a suitable ­transitional form for space when designing the volumes and build­ ing shell.

Various elements of spatial definition. Various spatial qualities result from the composition of vertical elements. Various energy fields result depending on the way the space is breached. Because the room implodes where the corners are explicit; by contrast, where they are merely implicit, there is an outward expansion.

Although the “tyranny of intimacy,” as Richard Sennett has called it, is still celebrating victories in its all-glass constructions, transparency’s promises of happiness have long since been exposed as a fraud. An increased trend to withdraw into the private has been observed since the 1990s. The reasons may lie, on the one hand, in the surfeit of visual stimuli and the increase of noise and air pollution, which go hand in hand with the aforemen­ tioned measures to increase urban density. On the other hand, however, the space for individual retreat is becoming increasingly important because there are in general fewer and fewer unoccupied spaces. These days, when a substantial corset of laws governs everyday life, and work too is subject to considerable heteronomy, people associate their own four walls with a last refuge of selfdetermination. Hence the experience of territorial boundaries is part of a sense of dwelling. 190

In his essay “Six Themes for the Next Millennium,” the architec­ ture critic Juhani Pallasmaa has written that it is time to break down the primacy of the visual in favor of a resensualization and re­ enchantment of the world. 6 In his view, architecture has the task of bringing back the inner world and at the same time mediating be­ tween external and internal reality—things that require of the ar­ chitect a “profound understanding of the phenomenological essence of the art of architecture.” In modernist residential architecture in particular, many elements that were once taken for granted were lost in an effort to economize and now have to be laboriously re­ discovered as new qualities. Buffer Zones and Transitional Spaces In premodern times, residential buildings featured such elements as covered forecourts, vestibules, verandas, loggias, and unheated winter gardens—a rich repertoire of peripheral structures that func­ tioned as intermediate spaces between inside and outside. Branded superfluous by modernism and its efforts to minimize and ra­ tionalize, for some time now there has been a trend to cultivate such marginal areas again. This movement was prepared by postmod­ ernism and its rediscovery of the drawing of boundaries between pri­ vate interior space and public exterior space. At the same time advances in building materials, a change in their status, and the broader architectural trend toward multiple-shell facades has led to the establishment of a new idea of architecture that has done away with the traditional concept of the facade as a wall that delim­ its space. The shell of the building is no longer conceived as a rigid demarcation but rather as a buffer zone composed of several layers, mediating between urban space and interior space and also between the poles inside–outside, bright–dark, cold–warm. For example, loggias that extend the full width of the building and ­replace the traditional perforated facade can be very appealing today, because they always offer both options. On the one hand, they are suited to evoking in viewers a feeling of permeability and reced­

Delugan Meissl Associated Architects, Town house, Vienna-Neubau, 1999–2001. Facade design by Herwig Kempinger. View of facade facing street, Loggia.—Only ­recently have transitional spaces begun to be adequately considered in the practice of architecture. They are extensions of the room that can be used in many ways.

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Kazuyo Sejima & Associates, Gifu Kitagata apartment building, Motosu, Gifu Prefecture, Japan, 1994–98. Living room.— ­Modern interpretation of the principle of interim spaces from traditional Japanese homes. The introduction of an additional layer of mobile slat elements produces an ambiguous spatial boundary that also serves as a way to regulate light.

ing from the architectural limitation; on the other hand, they also prevent a direct collision of private interior space and public ex­ terior space. More generally, the utility that can be derived from such a spatialization of the facade is diverse. Such a facade represents not only a special quality in a building’s communication and ­provides an additional space that can be used in many ways but also makes it possible to improve the lighting situation in the spaces ­behind it since the light enters more gently. The use of such features thus complies with the desire for comfort. Models for such transitional spaces can be found in traditional Japanese architecture, in which an additional access area is located as a buffer zone around the rooms inside. When combined with ­projecting roofs, this immerses interiors in soft, delicate light. Con­ temp­orary interpretations of this concept often employ semi­ transparent materials. They result in a bright interior marked by a cheerful serenity whose lighting can be further adjusted using ­flexible wall elements located on the inner layer. All these variations on the form have in common that the creation of transitional spaces or buffer zones always results in demarcations of space with multiple meanings. Unlike the traditional facade, this kind of shielding should not be equated with a barrier, that is, with the pro­ duction of a closed space: the exterior is never excluded entirely here, just as the interior does not just provide protection but gives the occupants the opportunity at any time to remove the boundary they have established themselves. The Veiled Gaze With the denial of the shadow’s magic origin, zones of half-light and semidarkness also lost their raison d’être. Only recently have they begun to surface again sporadically, being mentioned particu­ larly in connection with computer workstations where the interest in a semidarkness without contrasts is once again a question of seeing better. In homes, their significance is far more marginal, ­a lthough knowledge of the effect of subtle dimming and blurring could no doubt make a contribution to enriching the home en­ vironment atmospherically. The milky glow of moonlight has always given rise to deeper emo­ tions and suggestions than sunshine ever has. Likewise, the pale,

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dreamlike glow that results in a space when light shimmers through partially blind walls or is refracted and filtered by mem­ branes of varying thickness is well suited to touch the emotions and stimulate the imagination. On the turning point between bright and dark, translucence is a method for designing with light. The space is still determined by the light, without any concealing dark­ ness or dramatic effect. True masterpieces of light diffusion and manifestations using delicate fabric can be found in classical Japanese architecture, whose penchant for the weakly lit space is described wonderfully by the Japanese writer Junichiro Tanizaki in his book In Praise of Shadows. In contrast to European architecture, which is seen as “hard” and “white,” the Japanese culture is determined by an aesthetic of subtle nuances. To that end, several layers of per­ meable and porous constructions and materials are used to mitigate the light that enters and to break up shadows. In the architectural history of the Western world, by contrast, the cases in which space acts as a protector and collector of deliberate diffusions of surfaces are rather rare. One of the exceptions is Pierre Chareau’s Maison de verre, in which the construction and ma­ terialization act to catch and transform light, and the focus is on banning light and shadow in equal measure. Hence the large, trans­ lucent outer walls permit a lush influx of light that, tempered by glass bricks, falls only fleetingly on the various materials in the interior before seeping into the dark colors of the carpets and ­ furniture. Only in the recent past has there been the occasional residential building in which more semitransparent materials, multilayered building shells, permeated walls, and so on, have been employed. This new aesthetic of veiling is at once a welcome opportunity to re­ habilitate the desire for ornamentation and decoration that modern­ ism scorned. Thus decorative patterns not only function to soften the light that penetrates but also prevent unwanted views inward. In Arab architecture, fine-meshed wooden screens in front of window openings are common elements, since they permit those inside to see the street without being seen themselves. Memories are also being reawakened of an architectural element that has long since fallen out of sight in Western architecture: before modernism de­ manded our direct and undivided attention be focused on the world

SANAA (Kazuyo Sejima & Ryue Nishizawa), M House, Tokyo, 1996–97. View from the kitchen area through the living room and courtyard into the bedroom.—The ­aesthetic of veiling offers the option of keeping the outside wall as open as pos­ sible while still blocking unwanted gazes from outside.

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Pierre Chareau, Maison de verre, Paris, 1927–32. Dr. Dalsace’s consultation room facing the garden.—Translucent or opalescent light is consciously discreet; it is the material from which a quiet, lyrical, con­ templative atmosphere is created.

Francis Soler with Jérôme Lauth and ­Vincent Jacob, Residential building, rue Émile Durkheim, ­Paris, 1994–97. Interior, view.—The use of glass printed in color is also less about illumi­nating the ­interior than about muting the exterior or height­ening the feeling of space.

through enormous panorama windows, the norm was windows with muntins holding small panes. This had something comforting and intimate about it, since it cut manageable, bearable excerpts from reality and held the world at a distance. This effect is enjoying a renaissance in the use of grilles or wooden slats placed in front of the entire facade. The Hiding Place The possibility of withdrawing was something else sacrificed in the name of modern living. A feeling of security is felt primarily in places with niches, corners, or angles, whereas in the middle of the room the feeling is comparatively uncomfortable. The common saying “withdraw to a corner” expresses what everyone expects of such a zone: making it possible to escape the constant demands of society and define a protected, individual area. The corner becomes an indispensible place to which to retreat. The corner place is di­ verse: with a rapid turn of the body, people can fundamentally alter their relationship to the room: looking out of the corner offers a survey of the real world, while looking into the corner, and turning the gaze inwardly as well, enables one to dwell on one’s own thoughts. In the meanwhile, modernism’s efforts to use horizontal windows and flowing spaces to make a breach into inner life and the in­ wardness of the intimate interior has borne fruit. Formerly common architectural elements such as niches and bay windows have disap­ peared; there are no more hiding places and the hodgepodge of ­f urnishings and knickknacks dreaming away in a protected corner have been lost, just as gentle illusions had to give way to harsh lighting. The lack of such architectural elements and the excessive concentration on the design of the facade are partly responsible for the unexciting spatial situations found everywhere, which are as indifferent to individual appropriation as they are to the need of people who are seeking calm to have lower light levels. In order to prevent a further increase in excessive flooding with natural light, and to give shady rooms a chance once more, we need to find pleasure again in the whole wall, and thus to offer occupants both bright, active zones and dark, calm poles. Furthermore, carefully consid­ ered, calculated arrangement of the openings in advance should make it possible to encourage the formation of corners for retreat and ­areas for identity, so that the experience of lingering in a room is not only pleasant but also varied.

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Where voyeurism and exhibitionism get out of hand as mass phenomena, we have forgotten that there are legitimate needs to withdraw and establish distance: Alvar Aalto, Villa Mairea, Noormarrku, ­Finland, 1938–39. Fireplace in living room.—For Aalto, one of the requirements for living spaces is to form islands and places for retreat that grow out of a central common zone as individual elements. In this case, the curved side wall causes the light entering to flow. Inside and outside, light and shadow meet. Lux Guyer, Villa Im Düggel for Charles­Rudolph Schwarzenbach, Küsnacht, ­Canton of Zurich, 1929–31. Corner window in the library.

The Island of Light The fact that light can define its own, fictive space offers another opportunity to create a comfortable area of identity. This happens when the lighting is intensely focused and a zone is clearly de­lim­ ited in the room, while the rest of the room sinks into semidarkness or darkness. Such an effect occurs, for example, when sunrays are focused by an opening that is not especially large and fall into a relatively dark room or screened-off area. The resulting light space, in the form of a clearly perceptible spot on the floor that wan­ ders with the course of the sun, automatically attracts attention. In addition, as a kind of fenced-in territory, it can produce an atmo­ sphere of undisturbed intimacy. Viewers standing outside this brightened zone will feel attracted to it as if magnetically and will want to settle there. A comfortable armchair in that place will ­contribute to making this island of light an oasis, a place of concen­ tration. Meanwhile the rest of the room takes on an undefined ­dimension for those who linger in the illuminated zone. To attract attention it is generally better to work with small, de­ liberately placed light sources rather than large surfaces of uniform lighting. Experiments demonstrated that as early as the 1950s. Correspondingly, a local light source above a desk will make it easier to concentrate than when the room is lit uniformly every­ where. Moreover, islands of light can acquire a binding force and encourage communication and a sense of community, as, for example, when a group of people sit opposite one another at a brightly lit table. By contrast, uniform lighting—for which lighting technicians long demonstrated a weakness—destroys the social quality of a space and can even lead to uncertainty and a loss of ori­ entation or foothold. From that we may conclude that creating

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one or more zones of activities distinct from the remaining space is beneficial not only for spatial orientation but also for a sense of space generally. One prerequisite for the creation of an island of light is that the overall brightness of the room be at an appropriate level, that is, not all too high, as, for example, when the walls or the immediate surroundings are darker. This assumes that the position of the sun and the cast shadows over the course of a day and of the seasons must be studied early on and taken into account in the planning. The Home as a Place of Memory The perception of space is a learned skill. That has a considerable in­ fluence on the effect that space has on the viewer. The impression of space is thus highly subjective, which makes it more difficult to cat­ alog the criteria for its pleasant effects. When and to what extent a building or a space makes a positive impression—in this case a com­ fortable one—on its users is thus not dependent solely on the design or the materials used but also on the receptivity, psyche, emotional state, and education of the viewers. A number of senses, supplemen­ ted by impressions of the past, are addressed when seeing. The eye takes in information that it passes on to the brain. There it is fil­ tered and completed using other sensory impressions as well as ­impressions made in the past. Seeing is thus not simply a pure act of translation but rather also one of memory in which experience plays a role. Experience is based on personal memories—for example, how a person grew up and had his or her first experiences with spaces and objects and also the tradition of the culture in which he or she was born. The psychological state also plays a role. Percep­ tion is memory and, from a psychoanalytical perspective, “active work of the mind”: “Perception is ... not something passive that can be reduced to a synthetic act of the brain but is action-oriented and involves interpretation and memory.”7 Normally people feel well when something seems familiar, since the assessment of space is determined by individual experiences in the past. The actual process of perceiving a space is subject to a hierarchical principle that takes effect on walking into a room. First the facts of the room are registered—that is, size, proportions, and openings—then certain elements such as materials and window muntins are recognized, and finally there is a process of attribu­ tion—that is to say, the viewer uses associations to interpret what has been perceived. These associations determine subsequent behavior toward what has been perceived. In particular, lighting and color patterns from the past serve as key features that trigger associations with previous experiences of space. Because associations are based on a wealth of experiences, such factors as culture and climate influence the assessment of a space—which explains why people with different cultural backgrounds will have similar associations with a room’s brightness and darkness. Thus spaces from our daily lives become a point of reference for our assessment of other interiors. In central Europe, for example, most people are familiar with small to medium rooms lit from the side. Such rooms, which were often depicted in Dutch painting, have been extremely widespread in this part of the world since the ­seventeenth century. Users will not, however, necessarily prefer the lighting situations they encounter most frequently.

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An assessment of spatial effect is based on referential spaces that are familiar from everyday experience. Situations that ­deviate from that experience are perceived as “very bright” or “cavelike.” “Classic,” vertical window in an older apartment in Vienna. Jan Vermeer, Lady Writing a Letter with Her Maid, ca. 1670. Oil on canvas, 71.1 x 60.5 cm. National Gallery of Ireland.

The “typical” lighting situation is a flow of light that drops off massively toward the rear (daylight factors). Depending on the ­material and color, the floor will have small to medium reflections and will be highly illuminated near the window. The floor, how­ ever, is almost never perceived as a bright surface. The ceiling, which is usually white, is the brightest surface in the room, as a result of multiple reflections off the interior walls. The light patterns on the wall, by contrast, are far more varied. Depending on the degree of perforation, the color, and the decor, directly lit parts of the wall can seem extremely bright. We ascribe a certain character to a space accordingly and use such descriptions as pleasant or friendly. “We also determine whether an architectural space seems more ­modern or more old-fashioned, whether it radiates a private or a pub­ lic atmosphere.”8 Hence different building types trigger different clichés and evoke the associated words commonly used to describe them. The effect of a space—or rather, the assessment whether it seems positive and suited to a particular purpose—also depends on the ­expectations one has of the space. A situation that deviates from ex­ pectations can be assessed as very bright or as cavelike and stuffy. Such impressions can also change with time, since visual perception turns out to be a process that is constantly fed by new experiences. When planning rooms, therefore, it is necessary to consider the desires and expectations people have and will have of their en­ vironment and the lighting conditions in a particular room. 199

Lighting and the Experience of Space Light is crucial to experience a space. In 1917, the German architect Hermann Muthesius, one of the cofounders of the Werkbund, ­weary of the shallow cult of the facade among his fellow architects, emphasized: “A truly comfortable, habitable, cozy impression of the interior can be achieved without using the forms of high art but instead by the simplest means. Good proportions of the room itself, an effective supply of light, unified form, and harmoni­ ous colors are the only requirements that have to be satisfied before anything else. These are all requirements of a more general nature, fundamental rules that do not even necessitate any special financial expenditure.”9 “Distributions of light and darkness in the visual field produce spatial experiences of their own accord.”10 Although reality turns out to be much more complex and interwoven with various other parameters, it is nevertheless possible to attribute a certain character to architectural space that can influence one’s behav­ ior and state in a space. Whereas a room whose upper half is kept brighter while the lower half is darker will correspond roughly to a familiar situation, the reverse situation, with the upper part darker and the lower brighter, can easily result in an oppressive am­ bience that, like an overcast sky, evokes a storm or danger. When only the ceiling is dark, and the walls around it contrast brightly, it creates instead an impression of a protective ceiling. If the end wall is the brightest section of the room within the visual field—as happens when there is a large glass surface on just one side, such as the facade—this “tunnel situation” can have a dynamic effect: one feels drawn toward the light. If, by contrast, the end wall is a dark surface, while the rest of the room seems very bright, this signals rather a stationary state that promises stabilization and calm. These are, of course, just vague interpretations that should be thought of as the sole possible effects, since in practice they are ­superimposed with the individual associations of the users. Never­ theless, they give at least an impression of the influence that the

Typical spatial effect in situations with few colors (based on Volkher Schultz, Projekt Tageslicht: Licht und Architektur).

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Standard

Protection

Danger

Dynamics

Obstacle

Calm

Rudolph M. Schindler, Philip Lovell Beach House, Newport Beach, CA, 1922–26. ­Living room with horizontal articulation by means of two windows. Rudolph M. Schindler, Kings Road House (Schindler House), West Hollywood, CA, 1921–22. Schindler’s room with dark ­ceiling and window muntins. Armand Weiser, Hilde Goldstein House, ­Vienna-Döbling, 1933. Living room with reflecting ceiling.

­ istribution of brightness in a room can have on our psychological d sense of (well-)being. It is not just the position and form of the ­window that are significant but also the question whether it is in an end or side wall—depending on the viewer’s standpoint. Simply changing the amount of the wall that is open or the placement of the opening can cause the room to leave an entirely different impres­ sion on the users, since the appearance of architectural space is also dependent on how the lighting concept presents the metrical ­volumes. Such qualities of a space as cramped–spacious, freedom– enclosure can be emphasized or downplayed by altering the shape of the window, evoking in the occupants, based on their previous ex­ periences with space, an appropriate perception. There is, of course, no objective catalog of criteria for the effect of different types of windows on the room; nevertheless, it is possible to make some basic statements about their influence on the appearance of the room. 201

The Window as Hole The window as a hole in the wall is probably the most conventional lighting possibility. The boundaries of the space remain clear; there is an impression of being screened off, a feeling of security. A single window is an object: it establishes a relationship of mutual dependence between the light source and the space, much like that of figure and ground. A window placed on the central axis of the end wall not only radiates a certain static calm but also elon­ gates the room optically. If the opening is small relative to the shell, the problem of too much contrast in luminance can be solved with a reveal or with side windows. If the window is placed in the side wall, it makes the room seem broader. An opening placed away from the center also ensures a clearer demarcation into bright and dark and adds tension to the room in the form of asymmetry.

Luis Barragán, Prieto López House, ­Jardines del Pedregal, Mexico City, 1950. Living room. Hallway with window as hole level-mounted to the wall. Josef Hoffmann, Eduard Ast Summerhouse, Schiefling, Kärnten, 1923–24. Bed­ room with “classic” window as hole.

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Frank Lloyd Wright, John Storer House, Los Angeles, CA, 1923–24. Living room with row of windows.

The Row of Windows A row of windows tends to blur or even reverse the figure–ground relationship between the luminous objects and the wall they perfo­ rate. Nevertheless, despite the material “liberation” that results from a large open section—a series of windows by no means creates the impression of openness and need not result in the space being oriented toward it. On the contrary, a regular series of vertical win­ dows can actively contribute to drawing boundaries. That is the case, for example, when the sections of the wall between the windows form a series of columns that, filled in by the imagination, are ­perceived as a separating spatial boundary despite their permeability. In Frank Lloyd Wright’s John Storer House, the rhythm of col­ umns accompanying the long wall and the texture of the supports reinforce the perspective effect of depth that develops relative to the perforated front. In contrast to a uniform, flat-looking space with continuous windows with no supports, it is characterized by a modulated, highly rhythmic space thanks to its densities; it seems down-to-earth and protective. Several openings can combine to form a unified composition within a plane or can be stacked or loosely distributed, thus producing movement optically. The Window as Slit Moving a window away from the center of the wall into the corner can alter the entire character of the room: the partial dissolving of the edge blurs the spatial boundaries and dark corners of the room are illuminated. The light that enters floods over the wall that is perpendicular to the opening, at the same time turning it into a source of reflected light. An opening on the edge of a wall also gives the space a diagonal orientation and a certain dynamic. One interesting example of this is the stairwell in Richard Neutra’s Sten and Frenke House: thanks to its disposition in space, the win­ dow of the side wall resembles a long ribbon window that runs up to a wall panel placed perpendicular to it. Abutting this panel seamlessly, the narrow window format nevertheless seems to strive irresistibly toward the brightly lit stairwell. The tension of the situation is heightened further by the glazed end wall, whose stark contrast with the dark panel element in front of it directs the gaze toward what lies behind it.

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Hans Scharoun, Mattern House, Bornim, 1933–34. Workplace in living room with ribbon window. Richard Neutra, Sten and Frenke House, Santa Monica, CA, 1934. Stairwell with window as cut in wall.

Ribbon and Panorama Windows A long and sufficiently tall ribbon window in the center of the wall results in good, uniform lighting in the room. The relatively shadowless lighting offers few contrasts and ensures a sober, ­objective atmosphere. Because our habits of seeing have been influ­ enced by impressions derived from landscapes, the view of hor­ izontal layers implies a certain spatial expanse. If the opening is large enough, the view can even become a panorama; the space ceases to be closed off. As long as there is a small support present, however, the space seems framed, and the impression of a “window” is ­preserved. Vertical and Horizontal Slits Openings that run horizontally or vertically across the entire wall divide it into layers. The planes that terminate the space are sepa­ rated and look like panels independent of one another. Much like the ribbon window, a horizontal slit in the wall provides the space with even illumination that extends more or less homogeneously into the depth of the room, depending on the height of the slit. In the case of a vertical window format, by contrast, which extends from the floor to the ceiling, the room is divided into brighter and darker zones. If the opening is on the edge of the wall, the wall is ­illuminated by the light that floods in, and the contrasts are weaker. Such lighting can suggest a spatial continuity or even point the way toward something. Corner Windows Another way to heighten the tension of a room is to dissolve the corners—a measure that causes the room to force its way emphati­ cally outward. Another example by Richard Neutra shows how

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Richard Neutra, Moore House, Ojai, CA, 1952. Bedroom with corner window.

the volume of the space is lost when the window is extended around the corner. This dematerializing effect is not solely based on ­material transparency: it is reinforced by the uniform lighting, with few contrasts in luminance, and especially the bright corner that expands the space into the depths. Openings in the corner lend a diagonal orientation to the space and the planes in which the openings are arranged. This directing effect can be motivated by design reasons—for example, illuminating a dark corner. Openings in corners eliminate the edges of the planes in which they lie. The larger the opening, the less evident the corner. If the opening is ­diagonal, the corner blurs completely, and the room can expand past its enclosing planes. The Skylight Although skylights bring the most light into a room, they offer few visual connections to the surroundings. That is precisely how ­l ighting with skylights produces its special atmospheres. By means of selected, calculated accent lights, sufficient light can be provided even to areas located deep within the interior. The resulting light is regular and diffuse, diminishing as it moves from top to bottom; it can distinguish a particular area or draw attention to an object. If the opening is located on the edge between the wall and ceiling, some of the light that enters floods the wall and thus adds to the brightness in the room. A linear skylight running along the wall can give the room a direction.

Ladislav Žák, Villa Hain, Prague-Vysocˇ any, 1932–33. Corridor with skylight on second floor.

Lighting from Below A very low window conveys an introverted and intimate impression of space. It results in an accent of light with distinct zones along the floor. The light that enters through the opening directly onto the floor is diffused into the room by the floor and creates soft transi­ tions with no sharp edges. The resulting atmosphere lives from strong contrasts of light and dark and from the reversal of natural lighting relationships: the area near the floor is relatively bright, while the rest of the room is veiled in a dim half-light. No value is placed on communicating with the exterior space; concentration on the in­ terior is the architectural theme here.

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Tadao Ando, Ishii House, Hamamatsu, ­Shizuoka, Japan, 1980–82. Living room with low-lying window. Luis Barragán, Barragán House and Studio, Tacubaya, Mexico City, 1947–48. Living room with window wall.

The Window Wall An opening within a plane can grow to the point that it stops ­looking like a figure within a plane. Beyond that, it is a positive ele­ ment: a transparent plane surrounded by a frame. A window wall dissolves the vertical boundaries of the space and enables the room to expand beyond its physical limits. It not only opens the room to a broad backdrop that dominates all activities but also permits a relatively good illumination of the room. The wall sur­faces on the edge of the opening function like a frame that, much like a win­ dow reveal, ensures a far more uniform distribution of luminance than the “hole” window does. A Play with Lights and a Theater of Materials As household incomes rise and lifestyles become more pluralistic, the task for architecture in the early twenty-first century in­ creasingly lies in accommodating a desire for uniqueness. In con­ trast to eras when a certain image of proper living dominated, the interest of the occupants have shifted away from the functional qualities of the home to atmospheric and conceptual qualities. The focus is on a way of living beyond standards, put together by combining different spatial situations. In return, overly aes­ theticized spaces can easily refuse to appropriate and establish an individual ambience by countering the integration of objects for practical living. But the style of a dwelling emerges from the selfdetermination of the occupants, so the architect has to allow the traces of use. It is also very important for personal well-being in a space that the architectural design achieve a certain balance be­ tween enclosing and opening. For despite all the gloomy predictions, our behavior vis-à-vis spaces continues to be marked by a backand-forth between giving up and regaining a feeling of security, which includes the ambivalence of bright and dark.

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In residences in particular, rooms need to react elastically to changing needs, with places for retreat alternating with others for activity and exposure. The identity of a space is thus determined by its scale, the nature of its openings and the flow of light, and by the rhythm of light and shadow. An assessment or even possible anticipation of the effects of natural light will continue to be an­ ­abstract and difficult issue, given the complexity of lighting techno­ logy and the psychology of perception. Although it is possible to calculate and measure the physical qualities of a lighting situation, the process of seeing is also influenced by emotional factors that ­decide the success of a lighting concept. Built space is not just mate­ rialized space but also an imagined, personally arranged space of perception, in which the connotations of earlier memories also play a role.

Spatial and visual interplay of light, color, and water in Luis Barragán’s Gálvez House, Colonia Chimalistac, Mexico City, 1955.

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An aesthetic lighting design tries to make such images and ex­ periences useful. It ought to go beyond the objective of a passive aid to vision to contribute to attractive surroundings. It thus pays ­attention above all to the design value of light and hence to send­ing intelligible messages. Beyond the temporary drama of shadows or the geometry of patterns of light, moreover, it is possible to use light to touch certain memories or deliberately evoke moods. The concept of atmosphere, which has become an all-purpose meta­ phor these days, implies here a play with subjective experiences of space. The problem, however, lies in the difficulty of finding a uni­ versal prescription for the value of various lighting situations as ­experiences. Whereas the lighting pragmatist has a secure footing in technology, the value of light as an experience emerges only in the area between the world of architectural objects and the ­physical presence of the viewer.

Atmospheric natural lighting in a residence in Ahmedabad, India.

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Correspondingly, it calls on the architect’s ability to remem­ber and project, for a sensitivity to phenomena of light can at least be an important reference point for the design. Because we are ­accustomed to seeing spaces as stable objects, the powers of the imag­ ination also have to demonstrate their worth in ­dynamic effects of light and thus in changing manifestations. With ­regard to the as­ sessment of atmospheric qualities of specific ­lighting situations, ­observations in nature and meteorological experiences can serve as well. Contemplative moments, dimming, and effects resembling dawn and dusk can be reconstructed to some extent and translated to residential situations by appropriate means. The relationship of light and material is central to this process, since light requires surfaces on which to play. The fact whether the corresponding material is sealed, porous, ground, or polished has an important influence on the effect of the light and the overall impression of the space. The absorption, transmission, reflec­tion, and diffusion of light rays produce diverse possibilities for a drama­ turgy of light that the architect can use to conduct a concert of ­coincidences, incidences, and necessities. This can result in build­ ings of aesthetic and sensory power that counter the normality of excess light. Openings in the wall allow not only light but images from the outside into the room. The size, form, and number of windows plays a lesser role than their sensible placement. Thus the spectrum can range from the little peephole that draws attention to a par­ ticular detail outside to the enormous panorama window in which a specific image of the outdoors is placed in the proper light. Even a single sunray can suffice to remind us of the existence of the sur­ rounding exterior space, because the place and time enter the room along with it. Subtle interaction between open and closed, trans­ parent and sealed can also support the formation of corners for retreat and areas of identity and create a varied landscape of bright and dark spaces.

1 Joseph Roth, What I Saw: Reports from Berlin, 1920–1933, trans. Michael ­Hofmann (New York: W. W. Norton & Co., 2003), 117–18. 2 Pierre von Meiss, Elements of Architecture: From Form to Place (New York: Van Nostrand Reinhold, 1990), 164. 3 Riklef Rambow, “Laienurteile über Architektur,” http://wwwpsy.uni-muenster. de/inst3/AEbromme/web/veroef/1998/Arch5.htm (accessed May 10, 2008). 4 Wolfgang Marschall, “Behagen: Ethnologische Splitter aus Asien,” Werk, Bauen + Wohnen 90/57, no. 3 (2003): 42–47. 5 Friedrich Achleitner, “Vom Grunzen und Rekeln,” Baumeister 89, no. 7 (1992): 27. 6 Juhani Pallasmaa, “Six Themes for the Next Millennium,” Architectural ­Review 196 (July 1994): 74–79, here 77. 7 The psychoanalyst Wolfgang Leuschner, at the symposium Architektur und ­Wahrnehmung (Architecture and perception) in Frankfurt am Main, November 2002, quoted in Werk, Bauen + Wohnen 90/57, no. 3 (2003): 69. 8 Christoph Schierz, “Sehen im Lichte der Wahrnehmung: Wie wir unsere Welt ‘besehen,’” Archithese 28, no. 6 (1998): 30–35, here 35. 9 Hermann Muthesius, Wie baue ich mein Haus? (Munich: Bruckmann, 1917), 129. 10 Volkher Schultz, “Projekt Tageslicht: Licht und Architektur,” http://www.fvlr. de/downloads/Lichtarch1.pdf (accessed May 10, 2008).

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Best Of: Eleven Masters of Natural Light Landmark Concepts of Light

In architecture, light is spoken about with many voices. Frequently, however, the approach to natural light does not go beyond a claim to functionality. Although the evolution of architecture is neces­sari­ly linked with an evolution of its immaterial effect, discussions of ­architecture have thus far paid little attention to designing with light. The primary reason for that may be that there are no universally accepted definitions for dynamic, diverse spatial atmos­pheres. De­ termining criteria for the use of natural light is, ­moreover, also made more difficult by the fact that information that can be verified by science continues to be valued more highly than subjective ­design criteria that cannot be qualified. Even if the modernist eupho­ ria for brightness has resulted in surfeit, and the expectations for a high-quality planning of natural light are increasing, many archi­ tects have only limited knowledge in this field. Lighting can only be taken into account in a design by someone who knows what light can achieve in the first place and how it can be brought to bear in a focused way. That is why we are pres­enting here eleven ­architects with a distinct awareness of light whose buildings enable us to recognize and distinguish among symptomatic approaches to light and highly distinct lighting styles. At the same time, we ­attempt to identify specific effects of light and, as far as possible, classify them in order to heighten our appreciation of the various possibilities for designing with natural light. The following examples may serve as inspiration for dealing with natural light on multiple levels and may point out possible ­inadequacies in many con­­tem­porary buildings.

Richard Neutra, Moore House, Ojai, CA, 1952. View from living room.

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Le Corbusier and Pierre Jeanneret, Villa ­Savoye, Poissy, 1928–31. Living room. Le Corbusier, Villa Shodhan, Ahmedabad, India, 1951–56. Facade facing garden.

Le Corbusier: Purifying Light In the simplicity and purity of their geometric form, Le Corbusier’s early villas from the 1920s have not only proved to be successful ­attempts to give everyday life a new, purist framework but are also architectural manifestations of a new awareness of light. Le Corbusier, who engaged seriously with Greek and Roman archi­ tecture, discovered for himself the hard, rational light beneath the dazz­ling Mediterranean sun. In the spaces he created, light seems to be a ­purifying brightness that illuminates, unveils, and shines through. Obeying above all aesthetic rules, light is there to open up the design value of his compositions to the viewer’s gaze. Usually this took the form of a calculated interplay of several competing sources of natural light, with whose help he tried to dramatize the multiple meanings of the space. Light itself plays only a passive, subservient role in this: quoted by Le Corbusier in the building, it is allowed to help make the Euclidian bodies manifest, permitted to follow their sharp contours in order to create the clarity in the space that the architect so loved. In his late work, by contrast, Le Cor­ busier re­vealed himself more as a shaper of shadows who discovered the ­aesthetic and atmospheric potential of light for modernism and was interested above all in the shadows his sculptural facades cast. The philosophy of lighting of his late work is no longer ­determined by ratio but rather by émotion.

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Richard Neutra: Invigorating Light Richard Neutra’s radical opening of the building’s skin to the out­ side world mirrored modernism’s newly coined concept of the ­environment, which focused less on drawing boundaries than on connecting and linking the entire ecosystem. Influenced by an ­omnipresent “exchange of radiation,” Neutra envisioned the house as a living space in constant interaction with its inhabitants. His obsessive use of transparent building parts derived from a hope they had a positive effect on health. He believed a generous use of glass and reflective surfaces was suited to encouraging the transfor­ mation of energies available in the atmosphere, thus helping the ­residents find spiritual energy and joie de vivre. At the same time, light, reflec­tions, and oscillations between transparency and opacity were ­intended to provide visual stimulation and to help blur ­visually the distinction of the boundaries between inside and outside. Neutra’s concentrated breakdown of form—which found its architectural ­expression in the dematerialization of the ­ corner—seems to have definitively redeemed modernism’s promise of freedom.

Richard Neutra, von Sternberg House, ­Northridge, CA, 1935–36. Bathroom. Richard Neutra, Chuey House, Los Angeles, CA, 1956. Living room.

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Frank Lloyd Wright, Avery Coonley ­Playhouse, Riverside, IL, 1912–13. Interior. Frank Lloyd Wright, Taliesin: Wright’s house and studio, Spring Green, WI, 1911– 59. Wright’s study.

Frank Lloyd Wright: Vitalizing Light Frank Lloyd Wright, one of the founding fathers of modernism, claimed to have discovered fluid space. At the end of his long life, he characterized High Modernism’s tendency to demateriali­za­ tion as inhuman and criticized its buildings as “soulless ­ residences of the shelf” and an “immense prison of glass facades.” Although European modernism acknowledged Wright’s con­ tributions to revolutionizing the traditional spatial box, it regarded with ambivalent feelings the architectural vocabulary of this ­Japanophile, who sought to produce an almost mystical atmosphere in his designs. Wright, who appreciated the wealth of variety of surface materials and who accepted nature as the only teacher, strove to make the changes of the seasons and the hours of the day ­palpable in the building by means of the penetration of light. To that end, he worked with freestanding walls and ceiling panels to ­protectively surround and articulate the open plan. At the same time, he allowed light to penetrate from the sides—reflected ­multiple times—through horizontal and vertical slits and joints. In contrast to European architects, Wright placed much more ­emphasis on a nuanced handling of darkness and effective shadow­ ing. He did not want to leave unexploited any opportunity to offer light various surfaces for reflection. In his work, light played an active role; it lent the various, consciously selected materials ­every conceivable facet, modulation, and nuance of color and there­ by produced the atmospheric moods of light and color that later generations would remember.

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Alvar Aalto: Ephemeral Light Alvar Aalto occupied a position in Europe that was not unlike that of Frank Lloyd Wright with respect to his attitude toward nature and light. Unlike most of his contemporaries, Aalto was aware of the danger of a rootless international architecture. Not wanting to ­reduce light simply to brightness, he was of the view that the various phenomena of light should be combined in the interplay of the ­materials used and their surfaces with an architectural vocabulary that expressed and characterized the place. As a consequence, in his buildings he drew on a number of possibilities in order to make it possible to experience the fleeting Nordic light in his spatial ­concepts. His approach to light in his buildings is reminiscent of the atmosphere in Finland’s dense forests, in which light is filtered through clouds or foliage. For example, Aalto placed multifarious filters between inside and outside in order to refract the light. ­Elsewhere he allowed sunlight to penetrate the rooms directly, where it revealed itself as an illuminating spot but never as a means of flooding the space. Instead, Aalto created various light accents that varied in intensity over the course of the day. As constantly ­changing games with light, they lend his buildings the richly faceted character that has earned him a reputation as a “humanist” ­architect. Aalto succeeded in translating the modern fluid space into a metaphorical landscape by replacing the sober spatial framework with a flexible, highly differentiated spatial image that serves as a stage for light.

Alvar Aalto, Villa Mairea, Noormarku, ­Finland, 1938–39. Music room, projecting roof over entry, Stairway in living room.

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Louis I. Kahn: Purist Light What is hinted at by Aalto’s buildings was further refined by Louis I. Kahn in his massive building volumes. In his oeuvre, he turned away from modernism’s myth of transparency and thus led the way to an “after modernism.” Surrounded by transparent ribs, he sought protecting shells and hollows. For Kahn, light was “animated matter,” that is, light had to be activated by the resistant gravity and density of solid materials. Light was supposed to play with the structure and in particular with the mass, whereby, particularly in his later projects, the architecture served as a kind of resonance chamber that passes the light that streams in on to the interior as indirect radiation. In his minimalist architectural dialogue, Kahn dispensed with everything picturesque; no superficial detail should disturb the elementary order of his light-optimized spatial structure or detract from the sophisticated chiaroscuro painting with shadows from which his building volumes derived their plasti­c­ ity. Kahn was also the one who rehabilitated the window as a hole that modernism had done away with. The dual function of his famous T-shaped window resolved the contradiction between ­satisfying a hunger for light, on the one hand, and a need for security, on the other.

Louis I. Kahn, Margaret Esherick House, Chestnut Hill, PA, 1959–61. Southeast side of living room. Louis I. Kahn, Norman Fisher House, ­Hatboro, PA, 1960–67. Living room with corner window.

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Luis Barragán, Prieto López House, ­Jardines del Pedregal, Mexico City, 1950. Living room. Luis Barragán, Barragán House and Studio, Tacubaya, Mexico City, 1947–48. Living room.

Luis Barragán: Meditative Light Luis Barragán’s buildings articulate an experience with Ibero­Mexican, Catholic splendor, influenced by the architect’s admiration for Le Corbusier, which led to an uncommonly sculptural, angular architecture that plays virtuosically with light and shadow. His credo is the poetry of the plane and its many varieties. His ­experience with Mexico’s glaring sunlight—more a case of too much sun than too little—is reflected in a formal idiom of planar walls that avoid details, designed entirely to provide shade and preserve the coolness of the interior. As with Kahn’s oeuvre, his buildings are instruments for transforming light: light seems almost to bring to life the material, undisturbed by unnecessary accessories, and causes the structure of the usually colorful surfaces to glow. The walls are opened to the sun at strategically compelling points and often offer a spectacular view into lavish gardens. Usually these wall openings, with their unframed windows, are more like trans­ parent walls than windows. Not infrequently, a wall, as a cut end of the opening edge on the side, represents an introduction into the image being dramatized, which the viewer can experience as if peering into a zoetrope. The interiors of these minimalist buildings are dominated by a contemplative, meditative atmosphere. Barra­ gán loved shadow and the semidarkness that models spaces and creates a depth in which contours become blurry and the atmosphere peaceful. Usually the lighting that helps brighten the space is ­indirect, via the ceiling or side walls. With his carefully designed spaces for retreat of cheerful composure, Barragán withdrew from the purely functional aspect of living space; rather, he breathed into European modernism the very spirit of living and loving that many of his contemporaries lacked.

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Tadao Ando: Spiritual Light Tadao Ando developed his philosophy of light primarily by study­ ing the buildings of Le Corbusier, Barragán, and Kahn and then radicalizing their approach to natural light. Moreover, his buildings also feature specifically Japanese influences, such as his penchant for building velvety darknesses suited to blurring contours and strip­ ping objects of their gravity. Ando’s raw concrete architecture has great clarity and calm: firmly anchored in the earth, it seems timeless; only light moves within it. Whatever the Japanese architect builds, it radiates a magic, spiritual effect. Searching for the ­mysteries of light and space, Ando rejects the spectacular that in­ creasingly defines architecture today. In order to escape the ­tri­vialness of the surroundings, he invented the sunken building, in which the interior is shielded from the outside world by large ­enclosing walls. The view into courtyards with small areas of water or greenery is usually only through very low-lying windows, while the sunlight penetrates into the space here and there through slits and small incisions and joints eat into the walls. At the same time, Ando likes to introduce highlights, giving them space to traverse entire rooms as an autonomous design element. As a rule, daylight enters through openings hidden or veiled from the viewer, so that it does not coincide with the paths inside but rather serves to zone the interior. It is above all light’s quality of cre­ ating scale, of placing things in relation to one another that ­ Ando exploits for his buildings. Light for him is no longer some­ thing that provides brightness or illuminates form; instead, it obtains its own, independent presence.

Tadao Ando, Ishii House, Hamamatsu, ­Shizuoka, Japan, 1980–82. Living room.

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Jean Nouvel, Row houses, Cité manifeste, Mulhouse, 2001–5. Living room with ­gallery.

Jean Nouvel: Illusionistic Light Jean Nouvel, who denies having a personal style, prefers to see him­ self as a “stage director” among specialists. He loves vexation and seeks out the spectacular, which is why he develops a new lighting solution for each building. Even in residential buildings he is ­concerned to reformulate concepts; for example, in his effort to offer large spaces with variable interiors even in public housing. Some­ times he cunningly puts light to use to that end, overcoming ­partitioning spatial relationships by means of diffusive of translucent effects of interior and exterior walls. This results in fluid atmo­ spheres of suggestive power. Nouvel, who loves to counter the endur­ ing materiality and proportional clarity of architecture with a vision of the fleeting and manifold, feels utterly at home in the world of film. Many of his public buildings are distinguished by a rich and lively dramatization of light. For this he likes to col­ laborate with artists like Yann Kersalé, who creates stunning ­installations of artificial light for him. His own philosophy of natu­ ral light, by contrast, is expressed in materials or surfaces that ­manipulate light, whose reflective capacity is precisely calculated and whose grille and veil structures are given ornamental designs. ­Nouvel has proved to be a virtuoso of guiding light, as a master of illusionistic effects in which light penetrates glass walls and ceiling vaults; is refracted by perforated panels, grille sieves, and translucent filters; broken up; and then reflected by shiny polished metals and glossy lacquers. The protagonist of decorated surfaces demonstrates that with the help of diffused, reflected, ­colored, and dispersed natural light, they can be designed in as many ways as they can using the familiar methods of artificial light ­decoration.

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Toyo Ito, T House, Yutenji, Setagaya-ku, Tokyo, 1997–99. Stairway from entry; ­studio in the background.

Toyo Ito: Atmospheric Light Toyo Ito is a contemplative intellectual. With his buildings, he ­attempts to reflect both on the archaic need for security and the op­ portunities of a modern demarcation of space. For him, a house is something like a shelter, merely wrapped by a soft veil, around which the urban current of traffic and energy flows lap like water. Ito thus proves to be an early protagonist of semitransparency, devoted to textile tent architecture and extravagant perforated ­metal or frosted cloak glass. Much as his buildings never seem to be self-contained unities sealed off hermetically from the outside world, he also makes almost no subdivisions into spaces in his inte­ riors. Ito’s principle of levels layered behind one another aims ­rather at creating distinct areas that appear to have no center, no be­ ginning or end. These interior worlds are usually delimited by translucently glowing, windowless facades and gleaming ceiling soffits, which help the architect to draw a cloak of blurriness over his motifs. Sharp lines and edges thus dissolve in the fog of the indeterminate, while light and shadow transition into one another softly and almost imperceptibly. Just as transparent as the structure is, so varied are the impressions and feelings in Ito’s spaces, in which a magical moonlight dominates, conveying a sense of legerity. His architecture seems to be exempted from the laws of gravity.

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SANAA, Kazuyo Sejima, Ryue Nishizawa: Suggestive Light A former colleague of Toyo Ito, Kazuyo Sejima is also his master student. Together with her partner, Ryue Nishizawa, she takes Ito’s efforts to dematerialize even further. In their buildings, there are no longer any visible lines of bearing and forces. Architecture is re­ duced to a slender framework for changing impressions. Yet the ephemeral structures of this duo betray little of the clever planning on which the severe elegance and rigorous geometry of their ­designs are based. The frameless planarity so typical of their build­ ings is achieved via complex compositions of mirrorings, views through, and translucent surfaces that seem at once precise and po­ etic. Window and wall—open and closed—lose their usual con­ trasting effect and instead seem interchangeable. The consequence is an architecture without body or shadow that opens a new ­chapter: that of blurriness. Where once light and shadow emphasized space and form, sharp contours are now sacrificed to a plexus of coverings. The perfection of lighting and illumination of these two Japanese architects is no longer the total lighting of modernism and has equally little to do with an antimodernist, theatrical, or even atmospheric staging. Rather, they are searching for a true archi­­­ tecture of light, an architecture that moves on the edge of virtuality.

Ryue Nishizawa Office, Weekend house, Usui-gun, Gunma Prefecture, Japan, 1997–98. Interior with light wells.

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Steven Holl, Stretto House, Dallas, TX, 1990–92. Interior. Steven Holl, D.E. Shaw & Co. Offices, New York, 1992.

Steven Holl: Animating Light Steven Holl’s work is marked by the precise interplay of space, light, and material. Holl prefers sculptural forms comparable to modernism but dispenses with the latter’s functionalist principles and repetition of similar elements. The background for his work is rather his reflection on the phenomenological dimension of archi­ tecture and the connection between the sensory dimension of space and individual experience. The diversity of expression is accord­ ingly an important component of his architecture, which he tries to achieve through a playful confrontation of immaterial light and robust material. In that process, Holl does not view natural light in isolation but as part of a whole, and its influence transforms the shape of the architecture. He is interested in constantly chang­ ing light and the resulting ever-changing appearance of colored surfaces, by means of which he creates spatial compositions of great poetry and sensuality. His interiors are the result of well-thoughtout games with light and color in which the window openings and interior architecture are precisely harmonized. Usually the light falls into the room from different sides, overlapping as it appears on the plastic form. Holl likes to employ moving sky-, sun-, and ­daylight to animate his architectural sculptures, but sometimes he allows colorful highlights and indirect daylight to mutate the walls into colored surfaces like a canvas. His compositions are calcu­ lated to blur spatial boundaries: the guiding of light and color are intended to overwrite the corners, edges, and niches in order to suggest architectural fissures and spatial superimpositions where none exist.

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Selected Bibliography

Max Ernst Haefeli, Koellreuter House, ­Küsnacht, Canton of Zurich, 1931–32. Multiple layer window facade in front of the living area.

In general, we have found that in most cases the existing literature is very physical in orientation and thus all the more difficult for nonspecialists to understand. In ­addition to common standard works on the theme of housing, the two publications edited by Nick Baker and the handbook on lighting design by Peter Tregenza and David Loe became central works for our orientation. The series Jahrbuch Licht und Architektur that Ingeborg Flagge has been editing since 1992, which contains a wealth of essays from different perspectives, is also very important. Other stimulat-­­ ing compendia include the publication Architektur Licht Architektur, also edited by Ingeborg Flagge, and several special issues of journals such as Daidalos and Arch+. The probing studies of Gerhard Auer, who is one of the few authors who always strives for a comprehensive approach to the theme of daylight, should also be men-­­ tioned here. Whereas information from the Internet contributed to the quality of our work only in very limited ways, contact with architects, specialists, and users was far more informative. In particular, a meeting with Christian Bartenbach helped to focus considerably our perspective on dealing with natural light and led to the revision of several of our conclusions. Ultimately, however, it was Gerhard Auer whose exper-­­ tise and experience contributed the most to the success of the present volume.

Natural Light: Technology, Planning

Baker, Nick, A. Fanchiotti, and Koen Steemers. Daylighting in Architecture: A European Reference Book, London: James & James, 1993. ———, and Koen Steemers. Daylight Design of Buildings. London: James & James, 2002. Bartenbach, Christian, and Martin Klingler. “Tageslicht / Daylight.” In Ingeborg Flagge, ed. Jahrbuch für Licht und Architektur 1995, pp. 88–115. ­Berlin: Ernst & Sohn, 1996. Brandi, Ulrike, and Christoph ­Geissmar-­­Brandi. Lightbook: The ­Prac­tice of Lighting Design. Basel: Birkhäuser, 2001. Çakir, A. E., and Gisela Çakir. Projekt Tageslicht: Licht und Ergonomie. http://www.fvlr.de/downloads/­ Lichtergo1.pdf (accessed May 10, 2008). Detail Practice: Lighting Design: ­Principles, Implementation, Case ­Studies. Munich: Edition Detail, 2006.

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Evans, Benjamin H. Daylight in Architecture. New York: McGraw-Hill, 1981. Ganslandt, Rüdiger, and Harald ­Hofmann. Handbuch der Lichtplanung. Wiesbaden: Vieweg, 1992. Hopkinson, R.G. Architectural Physics: Lighting. London: HMSO, 1963. ———, and J. D. Kay, The Lighting of Buildings. 2nd ed. London: Faber and Faber, 1972. IEA (International Energy Agency). Several documents available, for example: “Task 21: Daylight in Buildings: Design Tools and Performance Analysis,” http://www.iea-shc.org/task21/index. html; “Task 21 Source Book,” http:// www.iea-shc.org/task21/index.html; “Task 31: Daylighting buildings in the 21st Century (current),” http://www. iea-shc.org/task31/index.html. On Task 31, see also the Swiss contribution by Nicolas Morel, Antoine Guillemin, and Jean-Louis Scartezzini (EPFL, ­S olar Energy and Building Physics Laboratory LESO-PB): http://www.

empa-ren.ch/Internet-Files/Programm/ Aktuelles/aktualitaeten/Status-Seminar/ pdf-files2004/Morel.pdf (accessed May 10, 2008). Köster, Helmut. Dynamic Daylighting Architecture: Basics, Systems, Projects. Basel: Birkhäuser, 2004. Olgyay, Aladar, and Victor Olgyay. ­Solar Control and Shading Devices. Princeton, NJ: Princeton Univ. Press, 1957. Phillips, Derek. Daylighting: Natural Light in Architecture. Oxford: ­A rchi­tec­­tural Press, 2004. Schultz, Volkher. Projekt Tageslicht: Licht und Architektur, http://www.­ fvlr.de/downloads/Lichtarch1.pdf ­(accessed May 10, 2008). Tregenza, Peter, and David Loe. The Design of Lighting. London: E & FN Spon, 1998.

Light, Space

Ackermann, Marion, and Dietrich Neumann, eds. Leuchtende Bauten: Architektur der Nacht / Luminous Buildings: Architecture of the Night. Exh. cat., Kunstmuseum Stuttgart. Ostfildern: Hatje Cantz, 2006. “The Architecture of Light.” Special ­issue of Daidalos, no. 27 (1988). Auer, Gerhard. “Ahnung und Planung: Zum Licht-Bewusstsein des Archi­ tekten.” In Ingeborg Flagge, ed. Architektur Licht Architektur, pp. 126–41. Stuttgart: Krämer, 1991. Reprinted in Ingeborg Flagge, ed. Jahrbuch Licht und Architektur 1998, pp. 86–97. ­Darmstadt: Das Beispiel, 1998. Baatz, Willfried, ed. Gestaltung mit ­L icht. Ravensburg: Ravensburger ­Buchverlag, 1994. Binet, Hélène, et al. Das Geheimnis des Schattens: Licht und Schatten in der Architektur / The Secret of the Shadow: Light and Shadow in Architecture. Exh. cat., Deutsches Architektur-Museum, Frankfurt am Main. 2nd ed. Tübingen: Wasmuth, 2002. Bollnow, Otto Friedrich. Mensch und Raum. 5th ed. Stuttgart: Kohlhammer, 1984 (first published in 1963). Breuer, Marcel. Sun and Shadow. ­London: Longmans, Green, 1956. Buonocore, Pablo, and Michael A. Critchey. Tageslicht in der Architektur. Sulgen: Niggli, 2001.

Büttiker, Urs. Louis I. Kahn: Licht und Raum / Light and Space. Basel: ­Birk­häuser, 1993. Flagge, Ingeborg, ed. Architektur Licht Architektur. Stuttgart: Krämer, 1991. ———, ed. Jahrbuch für Licht und ­Architektur 1992. Berlin: Ernst & Sohn, 1993. ———, ed. Jahrbuch für Licht und ­Architektur 1993. Berlin: Ernst & Sohn, 1994. ———, ed. Jahrbuch für Licht und ­Architektur 1994. Berlin: Ernst & Sohn, 1995. ———, ed. Jahrbuch für Licht und ­Architektur 1995. Berlin: Ernst & Sohn, 1996. ———, ed. Jahrbuch Licht und Archi­ tektur 1998. Darmstadt: Das Beispiel, 1998. ———, ed. Jahrbuch Licht und Arch­i­ tektur 2000. Cologne: Rudolf Müller, 2000. ———, ed. Jahrbuch Licht und Archi­ tektur 2001–2002. Cologne: Rudolf Müller, 2002. ———, ed. Jahrbuch Licht und Archi­ tektur 2003: Licht und Wahrnehmung. Darmstadt: Das Beispiel, 2003. Futagawa, Yukio, ed. Light & Space: Modern Architecture. 2 vols. Tokyo: A.D.A. EDITA, 1994. Hirdina, Karin. “Belichten, Beleuch­ten, Erhellen: Licht in den zwanziger Jahren.” Public lecture at the Humboldt­Universität zu Berlin, May 1995, http:// dochost.rz.hu-berlin.de/documents/ ovl/hirdina-karin/PDF/Hirdina.pdf (accessed May 10, 2008). ­Also: ­Hintergrund, no. 31 (2006): 21–45. Köhler, Walter, and Wassili Luckhardt. Lichtarchitektur: Licht und Farbe als raumgestaltende Elemente. Berlin: Bauwelt, 1956. “Kommende Transparenz.” Special ­issue of Arch+, nos. 144–45 (December 1998). Korn, Arthur. Glas im Bau und als ­Gebrauchsgegenstand. BerlinCharlotten­burg: Ernst Pollak, 1929. Translated as Glass in Modern Architec­ ture. London: Barrie & Rockliff, 1967. Kramer, Heinrich. “Die Renaissance des Tageslichtes: Die Geschichte eines langen Missverständnisses.” In ­I ngeborg Flagge, ed. Jahrbuch Licht

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und Architektur 1998, pp. 78–85. ­Darmstadt: Verlag Das Beispiel, 1998. Kramer, Heinrich, and Walter von Lom, Licht: Bauen mit Licht. Cologne: Müller, 2002. McGrath, Raymond, and A. C. Frost. Glass in Architecture and Decoration. London: Architectural Press, 1937 (rev. 1961). Meiss, Pierre von. The Elements of ­Architecture: From Form to Place. ­London: Van Nostrand Reinhold, 1989. Oechslin, Werner. “Light: A Means of Creation between Reason and Emotion.” Daidalos, no. 27 (1988): 22–31, 34–38. ———. “Lichtarchitektur.” In Ingeborg Flagge, ed. Architektur Licht Archi­ tektur, pp. 100–117. Stuttgart: Krämer, 1991. Pauly, Danièle. Barragán: Space and Shadow, Walls and Colour. Basel: Birkhäuser, 2008. Reichlin, Bruno. “The Pros and Cons of the Horizontal Window: The Perret– Le Corbusier Controversy.” Daidalos, no. 13 (1984): 65–78. Scheerbart, Paul. Glasarchitektur. Berlin: Der Sturm, 1914. Translated by James Palmes in Dennis Sharp, ed. Paul Scheerbart, “Glass Architecture” and Bruno Taut, “Alpine Architecture.” New York: Praeger, 1972. Schivelbusch, Wolfgang. Licht Schein und Wahn: Auftritte der elektrischen Beleuchtung im 20. Jahrhundert. Berlin: Ernst & Sohn, 1992. Schmoll gen. Eisenwerth, J. A. “Fenster­ bilder: Motivbilder in der europäischen Malerei.” In Beiträge zur Motivkunde des 19. Jahrhunderts, Studien zur Kunst des neunzehnten Jahrhunderts 6, pp. 13–165. Munich: Prestel, 1970. Selle, Gert. “Öffnen und Schliessen: Über alte und neue Bezüge zum Raum.” Wolkenkuckucksheim 9, no. 1 (2004). http://www.tu-cottbus.de/BTU/Fak2/ TheoArch/wolke/deu/Themen/041/ Selle/selle.htm (accessed May 10, 2008). Uhlig, Günther, Niklaus Kohler, and Lothar Schneider, eds. Fenster: Architek­tur und Technologie im Dialog. Brunswick: Vieweg, 1994. Völckers, Otto. Bauen mit Glas: Glas als Werkstoff, Glasarten und Glassorten, Glas in Bautechnik und Baukunst, Die Baubücher 17. Stuttgart: Julius Hoffmann, 1948.

“Vom Umgang mit Licht und Schatten.” Special issue of Der Architekt, no. 9 (1990). Wigginton, Michael. Glass in Archi­ tecture. London: Phaidon, 1996. Zajonc, Arthur. Catching the Light: The Entwined History of Light and Mind. New York: Bantam, 1993. Zanco, Federica, ed. Luis Barragán: The Quiet Revolution. Geneva: Skira; Barragan Foundation; Weil am Rhein: Vitra Design Museum, 2001.

Housing, Architecture

Alexander, Christopher, et al. A Pattern Language: Towns, Buildings, Con­ struction. New York: Oxford University Press, 1977. Banham, Reyner. The Architecture of the Well-tempered Environment. London: The Architectural Press, 1969. Becher, Ursula A. J. Geschichte des modernen Lebensstils: Essen, Wohnen, Freizeit, Reisen. Munich: C.H. Beck, 1990. Behne, Adolf. Der moderne Zweckbau. Munich: Drei Masken, 1926. Translated by Michael Robinson as The Modern Functional Building, ed. Rosemarie Haag Bletter. Texts & Documents. ­Santa Monica, CA: Getty Research ­Institute, 1996. “Between Inside and Outside.” Special issue of Daidalos, no. 13, 1984. Bittner, Regina, ed. Bauhausstil: Zwischen International Style und Lifestyle. Edition Bauhaus 11. Berlin: Jovis, 2003. Colomina, Beatriz. Privacy and Publicity: Modern Architecture as Mass Media. Cambridge, MA: MIT Press, 1994. Dirisamer, Rudolf, Gernot Figlhuber, and Ottokar Uhl. Wohnen: Ein Hand­ buch. Vienna: Löcker, 1984. Faller, Peter. Der Wohngrundriss. ­Ludwigsburg: Wüstenrot-Stiftung; Stuttgart: Deutsche Verlags-Anstalt, 2002. Flagge, Ingeborg, ed. Von 1945 bis heute: Aufbau, Neubau, Umbau. Vol. 5 of Geschichte des Wohnens. Stuttgart: Deutsche Verlags-Anstalt, 1999. Förster, Wolfgang. Housing in the 20th and 21th Centuries / Wohnen im 20. und 21. Jahrhundert. Munich: Prestel, 2006.

Giedion, Sigfried. Befreites Wohnen. Zurich: Orell Füssli, 1929. ———. Space, Time and Architecture: The Growth of a New Tradition. ­Cambridge, MA: Harvard University Press, 1941. Grandjean, Étienne. Wohnphysiologie: Grundlagen gesunden Wohnens. Zurich: Artemis, 1973. Hafner, Thomas, Barbara Wohn, and Karin Rebholz-Chaves. Wohnsied­ lungen: Entwürfe, Typen, Erfahrungen aus Deutschland, Österreich und der Schweiz. Basel: Birkhäuser, 1998. Häussermann, Hartmut, and Walter Siebel. Soziologie des Wohnens: Eine Einführung in Wandel und Ausdifferen­ zierung des Wohnens. Weinheim: ­Juventa, 1996. Kähler, Gert, ed. 1918–1945: Reform, Reaktion, Zerstörung. Vol. 4 of ­Geschichte des Wohnens. Stuttgart: Deutsche Verlags-Anstalt, 1996. ———. Wie gewohnt? Ein Buch über das Wohnen für die Sekundarstufe II. Leipzig: Klett, 2003. Köhler, Bettina. “Phantom Glashaus: Das ‘Un-Private’ als zeitgemässe städtische Lebensform—ein wider­ sprüch­liches Verlangen,” Werk, Bauen + ­Wohnen 89/56, no. 10 (2002): 20–25. ———. “Nichts als Illusion: Die ­Tröstung des modernen Komforts?” Werk, Bauen + Wohnen 90/57, no. 3 (2003): 4–9. Kruft, Hanno-Walter. A History of ­Architectural Theory: From Vitruvius to the Present. Translated by Rona Id Taylor, Elsie Callander, and Anthony Wood. London: Zwemmer, 1994. Lethen, Helmut. “Von der Kälte des Materials in den Zwanziger Jahren.” Daidalos, no. 56 (1995): 50–55. Löw, Martina. Raumsoziologie. ­Frankfurt am Main: Suhrkamp, 2001. Moravánszky, Ákos, ed. Architekturtheorie im 20. Jahrhundert: Eine kriti­ sche Anthologie. Vienna: Springer, 2003. Neutra, Richard. Mensch und Wohnen / Life and Human Habitat. Stuttgart: Alexander Koch, 1956. Petsch, Joachim. Eigenheim und gute Stube: Zur Geschichte des bürgerlichen Wohnens: Städtebau—Architektur— Einrichtungsstile. Cologne: DuMont, 1989.

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Reulecke, Jürgen, ed. 1800–1918: Das bürgerliche Zeitalter. Vol. 3 of Geschich­te des Wohnens. Stuttgart: Deutsche ­Verlags-Anstalt, 1997. Riley, Terence. The Un-Private House. Exh. cat., Museum of Modern Art. New York: Museum of Modern Art, 1999. Rybczynski, Witold. Home: A Short History of an Idea. New York: Penguin Books, 1986. Schivelbusch, Wolfgang. Geschichte der Eisenbahnreise: Zur Industrialisierung von Raum und Zeit im 19. Jahrhundert. Frankfurt am Main: Fischer, 1989. Selle, Gert. Die eigenen vier Wände: Zur verborgenen Geschichte des ­Wohnens. Frankfurt am Main: Campus, 1993. Sennett, Richard. The Fall of Public Man. New York: Alfred A. Knopf, 1974. Taut, Bruno. Die neue Wohnung: Die Frau als Schöpferin. Leipzig: ­K link­hardt & Biermann, 1926. Vetter, Andreas K. Die Befreiung des Wohnens: Ein Architekturphänomen der 20er und 30er Jahre. Tübingen: Wasmuth, 2000. Worpole, Ken. Here Comes the Sun: Architecture and Public Space in ­Twentieth-Century European Culture. London: Reaktion Books, 2000.

Illustration Credits Despite having made every effort to do so, the authors were unable to locate every ­single copyright owner. Upon notification, they are prepared to respond to ­legitimate claims with appropriate compensation. For the works of Theo van Doesburg, Walter Gropius, Ludwig Mies van der Rohe, Jean Nouvel, Gerrit Thomas Rietveld, and Hans Scharoun: © 2008 ProLitteris, Zurich For the work of Luis Barragán: © 2008 Barragan Foundation, Switzerland/ProLitteris, Zurich For the work of Le Corbusier: © 2008 FLC/ProLitteris, Zurich Cover Photo: Hans Eichenberger (Werner Stücheli, Schanzen­graben Apartment Building, Zurich, 1953–54. Roof terrace), Archiv St’A Stücheli Architekten Essay by Gerhard Auer Illustrations: © illumueller.ch

Page 8, 10, 30, 32 all, 35, 42, 67, 69, 70 l, 71 both, 72 b, 75 lt, 75 rb, 76, 81, 85 l, 90, 96 t, 97 both, 109, 116, 117 both, 118 r, 125, 138 b, 147 t, 152 br, 155 b, 159, 162 both t, 163 both r, 166, 172, 174, 175 t, 180, 188 b, 191 l, 199 l, 202 l, 207, 208, 212 b, 217 t, 231, 232. Photo: Viktor Jara—34 t, 55 b, 142, 224. Photo: Hans Finsler, gta Archives, ETH Zurich; © Stiftung Moritzburg, Halle/Saale—34 b, 78, 83. Photo: Walter Mair—36. Photo: Gemmerli, gta Archives, ETH Zurich—37 l. Philips Technical ­Review 20 (1958–59)—37 rt. Fotostiftung Schweiz, Winterthur—37 rb. Bruno Taut, Ein Wohnhaus (Stuttgart: Franckh’sche Verlagshandlung, 1927)—38, 39, 205 b. ­Photo: Illek & Paul, Národní technické muzeum v Praze, Archiv architektury a ­stavitelství—40. Deutsches Filminstitut—DIF, Frankfurt; © Friedrich-Wilhelm­Murnau-Stiftung/Transit Film GmbH—41 t, 49, 52, 53, 59 both, 66 t, 75 lb, 85 r, 92, 94 bl, 105 rt, 133, 147 bl, 147 br, 150 b, 152 m, 152 bl, 160, 204 l. Authors’ archive— 41 b. Photo: Julius Wilcke; © bpk, Berlin, 2004—45, 148, 149 r, 176, 177, 183 r, 202 r. Photo: Rupert ­Steiner—46, 50 b, 80-3, 102/103, 104, 115, 146 b, 213 l. Photo: Julius Shulman; © J. Paul Getty Trust. Used with permission. Julius Shulman Photography Archive. Research Library, The Getty Research Institute, Los Angeles, California— 48. Photo: Hubacher, gta Archives, ETH Zurich—50 t, 96 b. Photo: Rudolf de ­Sandalo, Muzeum města Brna—51. Fondation Le Corbusier, Paris—54. Daimler AG, Heritage Information Center—55 tl, 55 tr. Bruno Taut, Die neue Wohnung: Die Frau als Schöpferin, 4th ed. (Leipzig: Klinkhardt & Biermann, 1926)—56. Paul Artaria, Vom Bauen und Wohnen: Ein Bilderbuch für Laien und Fachleute, 4th ed. (Basel: Wepf, 1948)—57. Dieter Hundertmark, Räume im rechten Licht (1964)— 60. Internationale Kongresse für Neues Bauen, ed. Die Wohnung für das Existenzminimum: Einhundert Grundrisse (Frankfurt am Main: Englert & Schlosser, 1930)— 61 l. Werk 43 (1956)—61 r. Photo: Michael Wolgensinger, gta Archives, ETH Zurich; © 2008 Fotostiftung Schweiz/ProLitteris, Zurich—62 lt. Photo: Leonardo Bezzola, Archiv Atelier 5—62 lm, 62 lb, 62 r: Werk 48 (1961)—63 all. Arkitekten 53, no. 12 (1951)—64 lt. Das neue Frankfurt 5 (1931)—64 rt. Der Aufbau 14 (1959)—64 lb, 64 rb. Deutsche Bauzeitschrift, ed. Verdichtete Wohnformen (Gütersloh: Bertelsmann, 1974)—65. Photo: Rob Gnant, Werk 48 (1961)—66 m. Werk 45 (1958)—66 b, 80-2, 118 l, 155 t, 215 lt. gta Archives, ETH Zurich—68 t. Photo: Sigfried Giedion, ­ gta Archives, ETH Zurich—68 b. Le Corbusier, Textes et planches / L’atelier de la recherche ­patiente (Paris: ­Vincent, Fréal, 1960)—70 r. Franz Schuster, Balkone: ­Balkone, Lauben­gänge und Terrassen aus aller Welt (Stuttgart: Julius Hoffmann, 1962)—72 t. Photo: Fred Boissonas, gta Archives, ETH Zurich—73, 185 b. Photo: Reto Gadola—74 t. Walter Jonas, Das Intra-Haus: Vision einer Stadt (Zurich: ­Origo, 1962)—74 b. Photo: Albert Winkler, Staatsarchiv Bern—75 rt. BKK-3—80-1, 89. Bildarchiv Foto Marburg—80-4. Lacaton & Vassal—82 l. © bpk, Berlin, 2004— 82 r. Michael Sowa—86, 87 both, 88 all. ­Albertina, Wien—91. © bpk / Nationalgalerie, Staatliche Museen zu Berlin, Photo: Jörg P. Anders—93. Photo: Martin Gerlach (t), Photo: Jan Štenc (b), Umělecko­průmyslové museum v Praze—94 t. Theo van ­Doesburg, Grundbegriffe der neuen gestaltenden Kunst (Munich: Langen, 1925)— 94 br. Photo: Frank den Oudsten—95. Innendekoration 45 (1934)—99. Moderne

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Bauformen 34 (1935)—100. Photo Péter, gta Archives, ETH Zurich—101, 212 t. ­Photo: M. Gravot, gta Archives, ETH Zurich—105 l, 105 rb, 106 both. Photo: Ezra Stoller © Esto—107 l, 188 t, 216 both. Photo: Urs Büttiker—107 r, 145. Photo: ­Yukio Futagawa, GA: Global Architecture, no. 76 (1996)—111 l, 164 rb, 192, 193, 221. Photo: Hisao Suzuki, El Croquis 77(I) + 99 (2000)—111 rt, 119, 120 both, 157 tr, 157 br, 167 bl, 191 r. Photo: Margherita Spiluttini—111 rb, 122, 123, 143 b. Photo: Eduard Hueber—113. Photo: Ben Schnall, Marcel Breuer Papers, Archives of ­A merican Art, Smithsonian Institution—121. Photo: Horstheinz Neuendorff, ­Süd­westdeutsches Archiv für Architektur und Ingenieurbau, Universität Karlsruhe (TH), Werkarchiv Egon Eiermann—128. Photo: Peter Hemann, gta Archives, ETH ­Zurich—132. Heinrich Hebgen, Bauen mit der Sonne. Vorschläge und ­A nregungen (Essen: Rheinisch-­Westfälisches Elektrizitätswerk AG—Heidelberg: Energie-Verlag, 1982); Drawing and adaptation: Gabriela Rutz—134, 138 t, 139 both t, 143 t. © Nick Baker and Koen Steemers; Drawing and adaptation: Gabriela Rutz— 139 bl. © Roset ­Möbel GmbH, Gundelfingen, Germany—139 br, 141 lb, 141 rt. ­Photo: Peter Eder—140 t. Willy Boesiger and Oscar Stonorov, eds. Le Corbusier und Pierre Jeanneret: Ihr gesamtes Werk von 1910–1929 (Zurich: Girsberger, 1930)— 140 b, 154. © Nick Baker and Koen Steemers; Drawing: André de Herde—141 lt. R.G. Hopkinson, ­Architectural ­Physics: Lighting (London: HMSO, 1963)—141 rb. Weichlbauer, Ortis—144. Bartenbach LichtLabor—146 t. Photo: Ruedi Walti—149 l. querkraft—150 t, 150 m. Photo: Nicholas Kane, arcaid.co.uk—151 t, 151 m. Photo: Gerald Zugmann—151 b. ­archiguards—152 both t. Photo: Christian Richters—153. Delugan Meissl ­Associated Architects—156 both l. Steidle Architekten—156 r. ­Photo: Reinhard ­Görner—157 tl, 157 tm, 157 bl, 165, 170. Drawing: Gabriela Rutz—158, 175 both b. Photo: Bruno Klomfar—161 l, 196. Photo: Richard Weston—161 r, 206 r. Photo: ­Armando Salas ­Portugal; © Barragan Foundation, Switzerland/ProLitteris, Zurich—162 b. Photo: Klaus Frahm—163 l, 217 b. Photo: Yukio Futagawa, GA. ­Global ­Architecture, no. 48 (1979)—164 both l. © Franck Hammoutène—164 rt. Photo: ­Rien van Rijthoven—167 lt. Photo: Danièle Pauly—167 br. Photo: Martin Schranz—168 t. Photo: Jérôme Habersetzer—168 b. Photo: Lucien Hervé; © Research Library, ­The Getty Research Institute, Los Angeles, California, 2002.R.41—169 t. Étienne Grandjean, Wohnphysiologie: Grund­lagen gesunden Wohnens (Zurich: ­A rtemis, 1973)—169 b. Photo: © Paul Ott, Graz—171. Detlef Glücklich, Energieund ­kosten­bewusstes Bauen von Wohnhäusern (Cologne: Rudolf Müller, 1985); ­Drawing and adaptation: Gabriela Rutz—173. Photo: Walter Binder, gta Archives, ­ ETH Zurich—181. Photo: Ralph Hut—183 l. Lotte Tiedemann, Menschlich wohnen: Lebensvorgänge als Grundlage zur Wohnungs­planung (Bonn: Domus, 1956)—185 t, 201 lt. Architecture & Design Collection, ­University Art Museum, University of ­California, Santa Barbara, R. M. Schindler Collection—186. Innendekoration 42 (1931)—187. Fred Fischer, Der Wohnraum (Zurich: Artemis, 1965); Drawing and ­adaptation: Gabriela Rutz—189. Courtesy, Museum of Fine Arts, Boston, The ­Hayden Collection—Charles Henry Hayden Fund; Photograph © 2008 ­Museum of Fine Arts, Boston—190 all. Pierre von Meiss, De la forme au lieu: Une ­introduction à l’étude de l’architecture (Lausanne: Presses polytechniques romandes, 1986)—194 t. Photo: Jordi Sarrà—194 both b. ­Francis ­Soler—197. Photo: Ernst Linck, gta Archives, ETH Zurich—199 r. Courtesy of The ­National Gallery of ­I reland; Photograph © The National Gallery of Ireland—200. Volkher Schultz, ­Projekt ­Tageslicht: Licht und Architektur; Drawing and adaptation: Gabriela Rutz— 201 lb. Photo: Ulrike Schröer—201 r. ­Moderne Bauformen 32 (1933)—203. Photo: Michael Freeman—204 r. UCLA Library, Department of Special Collections—205 t, 210. Photo: Julius Shulman, gta Archives, ETH Zurich; © J. Paul Getty Trust. Used with permission. Research Library, The Getty Research Institute, Los Angeles, ­California—206 l, 218 both. Photo Yoshio Takase, ­© RETORIA, GA Architect, no. 8 (1987)—213 r. Photo: Arthur Luckhaus, UCLA Library, Department of Special Collections—214 l. The Frank Lloyd Wright ­Foundation, Scottsdale, AZ— 214 r. Photo: Paul Rocheleau—215 lb. Photo: Eino Mäkinen, Alvar Aalto Museum, 215 r. Alvar Aalto Museum; both © Alvar Aalto Museum/Alvar Aalto Foundation— 219. Photo: Philippe Ruault—220. Photo: Shinkenchiku-sha, Andrea ­Maffei, ed. ­Toyo Ito. Works, Projects, Writings (Milano: Electa, 2002)—222 both. Photo: Paul Warchol

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On the Authors Gerhard Auer Gerhard Auer, born in 1938, is a professor and licensed architect. He received his ­degree in architecture from the Universität Stuttgart in 1965; since 1967 he has been a practicing architect and urban designer. Since 1980, he has been professor for ­design at the Technische Universität Braunschweig. Also conducted research and pro­ vided expert opinions in Germany and abroad. Published many articles on ­a rchi­tectural theory and served as coeditor of the journal Daidalos. Since the 1980s he has concentrated on the topic of light: light, color, and sound as media in ­a rchitecture, theory and practice of lighting design in public spaces, urban concepts for light, and curating light art. Recent publications: “Die Baukünste des Zwielichts: Notizen zu einer Architektur der Autolumineszenz,” in Licht ist nicht sichtbar— ­L icht macht sichtbar, exh. cat. (Frankfurt am Main: Fachhochschule Frankfurt am Main, 2006); “Meta-Dekor: Zur Lichtkunst im öffentlichen Raum,” Die Alte Stadt, no. 1 (2007), focusing on the city in light; and “Space, Light, and Sight,” in Andreas ­Huber, ed. New Approaches to Housing in the Second Half of Life, Living Con­cepts 2 (Basel: Birkhäuser, 2008). Internet: www.gerhardauer.de Michelle Corrodi Born in 1971, she received her architecture degree from the ETH Zurich. 2000–2001: Assistant to Professor Herbert Kramel in the Faculty of Architecture at the ETH Zurich; 2002–8: Academic associate at the ETH Wohnforum. 2005–8: Copywriter in the architectural office of Baumschlager & Eberle; since 2008: Assistant managing director at Hauptmann & Kompanie advertising agency, Munich and ­Zurich. Klaus Spechtenhauser Born in 1969, MA, art history and Slavic languages and literature. Since 2002: ­academic associate at ETH Wohnforum; 2002–7: Assistant to Professor Arthur Rüegg in the Faculty of Architecture at the ETH Zurich. Active as a journalist on archi­ tectural and cultural history of the twentieth century; editing and copyediting of several publications. Editor of, among other works, The Kitchen: Life World, Usage, Perspectives, Living Concepts 1 (Basel: Birkhäuser, 2006); with Arthur Rüegg: Charles-Edouard Jeanneret/Le Corbusier: Maison Blanche; History and Restoration of the Villa Jeanneret-Perret, 1912–2005 (Basel: Birkhäuser, 2007). Currently ­working on a ­dissertation on the Czech architect Jaromír Krejcar.

Acknowledgments Special thanks to: Christian Bartenbach (Bartenbach LichtLabor, Aldrans, Austria), Ingrid Bell (copyediting), Muriel Comby, Dietmar Eberle, Reto Gadola, Sylvia Halm, Andreas Huber, Daniel Morgenthaler (Birkhäuser), Angela Müller, Lukas von Orelli (Velux Stiftung), Gabriela Rutz, Christoph Schierz (Center for Organizational and ­Occupational Sciences—ZOA, ETH Zurich), Daniel Weiss (gta Archives, ETH ­Zurich), Andrea Wiegelmann (Birkhäuser), as well as numerous friends and acquain­ tances whose comments and inspiration influenced the present work.

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Other volumes of Living Concepts: Klaus Spechtenhauser (ed.) The Kitchen: Life World, Usage, Perspectives Living Concepts 1 ISBN 978-3-7643-7281-1 2006. Birkhäuser Andreas Huber (ed.) New Approaches to Housing for the Second Half of Life Living Concepts 2 ISBN 978-3-7643-8635-1 2008. Birkhäuser