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1Edition: 20/03/2007 | Updated version at www.erco.com

Basics

Simulation and calculation

Indoor lighting

Lighting control

Designing with light

Outdoor lighting

Lighting technology

Glossary

The Guide provides extensiveinformation on topics rangingfrom the physical basics of light-ing through to possible solutionsfor specific lighting situations

in short, a veritable encyclo-paedia of architectural lighting.The knowledge modules makeuse of the interactive possibilitiesoffered by the Internet, e.g. forillustrating time-dependent phe-nomena, experiments or contrastsbetween alternative solutions:www.erco.com/guide

E Guide


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E GuideBasics

It is inadequate simply to portraythe eye as an optical system whendescribing human perception. Italso needs to be explained howthe image is interpreted. Both theperceptual psychology and theobjects of perception are impor-tant factors in understandinglighting design.

History Seeing and percep-tion


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E GuideBasics

History

Right up until the 18th centurypeople only had two light sourcesat their disposal: natural daylightand the flame the latter beingthe only artificial light sourcesince the Stone Age. These twotypes of lighting dictated thepatterns of life and architecturedown through the ages, but anew epoch was ushered in withthe invention of gas lighting and

then electric lighting.

Quantitative lightingdesign

Qualitative lightingdesign

Perception-orientatedlighting design


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With the advent of electricallighting, obtaining illuminancelevels similar to those of daylightbecame a question of how muchtechnical effort one was prepared

to invest. At the end of the 19thcentury, one attempt at provid-ing street lighting was to mountfloodlights on lighting towers.However, the glare and harshshadow produced caused moredisadvantages than advantagesand so this form of outdoor light-ing was soon abandoned.Whereas inadequate light sourceswere the main problem initially,a prime concern later on washow to sensibly deal with theoverabundance of light. Increas-ing industrialisation gave rise tointensive studies in the field ofworkplace lighting, investigat-

ing the influence of illuminancelevels and lighting type onproduction efficiency. The stud-ies resulted in extensive rulesand regulations governing theminimum illuminance levels, thequalities of colour rendition andglare limitation. This catalogueof standards was to serve as aguideline for lighting far beyondthe area of the workplace; in fact,it still determines the practiceof lighting design right up tothe present day. However, thisapproach left the psychology ofperception totally unconsidered.The issues of how people perceivestructures clearly and how light-ing also conveys an aestheticeffect were beyond the scope ofthe quantitative lighting rulesand regulations.

The American Electric Light Tower(San Jos 1885)

E GuideBasics | History

Quantitative lighting design


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Restricting the view of humanperception to a physiologicallyorientated level led to unsat-isfactory lighting concepts.Approaches at a new lightingphilosophy that no longer solelyconsidered quantitative aspectsarose in the USA after World WarII. Expanding the physiology ofthe visual apparatus by addingthe psychology of perception

meant that all factors involvedin the interaction between theperceiving observer, the objectviewed and the facilitatingmedium of light now came underconsideration. The perception-orientated lighting design nolonger primarily thought in thequantitative terms of illuminancelevels or luminance distribution,but in terms of the qualitativefactors.


Qualitative lighting design


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Perception-orientated lighting design

The perception-orientatedlighting design of the 1960s nolonger considered man and hisneeds as a mere recipient of hisvisual surroundings but as anactive factor in the perceptionprocess. The designers analysedwhat was the significance of theindividual areas and functions.Using the pattern of meaningthus established, it was then

possible to plan the lighting asa third factor and to develop anappropriate lighting design. Thisrequired qualitative criteria and acorresponding vocabulary, whichin turn allowed both the require-ments placed on a lighting systemand the functions of the light tobe described.

Richard Kelly William Lam


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Richard Kelly (1919-1977) wasa pioneer of qualitative lightingdesign who borrowed existingideas from perception psychol-ogy and theatrical lighting and

combined them into a uniformconcept. Kelly broke away fromthe rigid constraints of using uni-form illuminance as the centralcriterium of the lighting design.He replaced the question of light-ing quantity with the question ofindividual qualities of light. Thesewere designed according to aseries of lighting functions, whichwere in turn geared towards theperceiving observer. In the 1950sKelly made a distinction herebetween three basic functions:ambient luminescence, focal glowand play of brilliants.

E GuideBasics | History | Perception-orientated lighting design

Richard Kelly

Introduction


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Richard Kelly

Focal glow

To arrive at a differentiation,Kelly came up with a secondform of light, which he referredto as focal glow. This is wherelight is first given the expresstask of actively helping to con-vey information. The fact thatbrightly lit areas automaticallydraw our attention now comesinto consideration. By using asuitable brightness distributionit is possible to order the wealthof information contained in anenvironment. Areas containingessential information can beemphasised by accented lighting,whereas secondary or distracting

information can be toned down

Play of brilliantsThe third form of light, playof brilliants, results from theinsight that light not only drawsour attention to information, butcan also represent information inand of itself. This applies aboveall to the specular effects thatpoint light sources can produceon reflective or refractive materi-als. Furthermore, the light sourceitself can also be considered to bebrilliant. This play of brilliantscan add life and ambiance, espe-cially to prestigious venues. Whatwas traditionally produced bychandeliers and candlelight cannow be achieved in a modernlighting design by the targeteduse of light sculptures or by cre-ating brilliant effects on illumi-nated materials.

Ambient luminescenceKelly called the first and foun-dational form of light ambientluminescence. This is the elementof light that provides general

illumination of the surroundings;it ensures that the surroundingspace, its objects and the peoplethere are visible. This form oflighting facilitates general orien-tation and activity. Its universaland uniform orientation meansthat it largely follows along thesame lines as quantitative light-ing design, except that ambientluminescence is not the finalobjective but just the founda-tion for a more comprehensivelighting design. The aim is not to

produce blanket illumination, orone size fits all lighting at thesupposed optimum illuminancelevel, but to have differentiatedlighting that builds on the base

layer of the ambient light.

by applying a lower lighting level.

This facilitates a fast and accurateflow of information, wherebythe visual environment is easilyrecognised in terms of its struc-tures and the significance of theobjects it contains. This appliesjust as equally to orientationwithin the space (e.g. the abilityto distinguish quickly between amain entrance and a side door) asfor emphasising certain objects,such as when presenting goodsfor sale or when highlighting themost valuable sculpture in a col-lection.


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Richard Kelly

Glass House

Architect: Philip JohnsonLocation: New Canaan,Connecticut, 1948-1949

It was on this Glass House projectthat Kelly developed the basicprinciples of indoor and outdoorlighting which he was to laterapply to countless residential andbusiness properties. Kelly avoidedthe use of blinds for the sunlightbecause he found they obscuredthe view and impaired the feel-ing of distant space. Instead, toreduce the harsh daytime bright-ness contrast between insideand outside, Kelly used dimmedlighting on the interior walls. Forthe night, he designed a conceptthat works with the reflection

of the glass facade and retainsthe spatial feeling. Kelly recom-mended candles for the interioras this would give sparkle and addan exciting atmosphere. Severallighting components in the out-door area augment the view outof the living area and create spa-tial depth. Projectors on the roofilluminate the front lawn and thetrees beside the house. Additionalprojectors highlight the trees

in the middle ground and thebackground, thereby making thelandscape backdrop visible.

Photos courtesy of the Kelly

Collection.

Seagram Building

Architects: Ludwig Mies van derRohe and Philip Johnson

Location: New York, New York,1957

The vision behind the SeagramBuilding was to have a tower oflight that would be recognisablefrom afar. Working together withMies van der Rohe and PhilipJohnson, Kelly achieved this aimby having the building shine fromthe inside out. This was doneusing luminous ceilings in theoffice levels, whereby a two-stagelight switch for the fluorescentlamps enabled energy to be savedat night. The illumined area at theplinth of the building gave theimpression that this multi-storeybuilding is floating above thestreet. An impressive view intothe building at night is affordedthanks to uniform vertical illu-mination of the buildings core,produced by recessed ceilingluminaires. A carpet of light startsin the indoor area and continuesonto the forecourt. To achieve auniform pattern of solar protec-tion on the facade during thedaytime, the blinds on the win-dows only have three settings:open, closed and half-open.


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Richard Kelly

New York State Theater

Lincoln Center for the PerformingArtsArchitect: Philip Johnson

Location: New York, New York,1965

For the New York State TheaterKelly explored the use of crystal-line structures for the design ofthe chandelier in the auditoriumand the lighting of the balconybalustrades in the foyer. Thechandelier in the auditorium hada diameter of about three metersand consisted of a number ofsmaller diamonds of light. Inthe foyer, the luminaires on thebalustrade were designed to looklike jewels in a crown, therebyunderlining the grandeur of the

room. The light sources wereshielded towards the front side ofthe balustrades, but on the insidetheir multi-facetted structureproduced impressive reflections.This results in brilliance effectscomparable with the sparkle ofprecious stones. In addition, Kellyalso conceived the lighting in allthe other areas of the LincolnCenter, except the interior of theMetropolitan Opera House.

Kimbell Art Museum

Architect: Louis I. KahnLocation: Fort Worth, Texas, 1972

The clever use of natural lightin the Kimbell Art Museumoriginates from the teamworkof Louis Kahn and Richard Kelly.Kahn designed a series of North-South orientated galleries whosevaulted ceilings featured a sky-light running along their apexes,while Kelly was responsible forthe daylight reflector systemmade of curved aluminium plate.Perforations allow daylight topenetrate through this plate,thereby reducing the contrastbetween the underside of thisreflector and the daylight-illu-minated concrete vaulting. Thecentral section of this dishedaluminium is kept free of per-forations so that direct daylightis shut out. In areas with no UVprotection requirements, such asthe entrance or the restaurant, acompletely perforated reflectoris used. Computer programs wereused to calculate the reflectorcontour and the lighting proper-ties that were to be expected.The underside of the daylightreflector system was fitted withtracks and spotlights. Kelly sug-gested putting plants in the inner

courtyards in order to tone downthe harsh daylight for the indoorareas.


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Richard Kelly

Yale Center For British Art

Architect: Louis I. KahnLocation: New Haven,Connecticut, 1969-1974

Louis Kahn teamed up with Kellyto design a system of skylightsfor the illumination in the YaleCenter for British Art. The designbrief from the museum was thaton sunny and overcast days thepictures were to be exclusivelyilluminated by daylight. Artificiallighting was only to be mixed inwhen there was very low daylight.The domed skylights feature apermanently mounted louvreconstruction on the topside,allowing diffuse northern lightinto the building while avoidingdirectly incident light on walls or

floors when the sun is high. Theskylights are made of an upperPlexiglas dome with UV-protec-tion and a sandwich construc-tion consisting of: a translucentplastic plate for dust protection,a mirror-finish light diffuser anda bi-laminar, acrylic, prismaticlens underneath. Tracks on theundersides of the domed skylightshold wallwashers and spotlights.The design process utilised com-puter calculations and full-scalemodels.


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Activity needsThe activity needs describe theneeds resulting from perform-ing activities within a visualenvironment. The characteristics

of the visual task at hand are thecrucial factor for these needs. Theanalysis of the activity needs istherefore largely identical withthe criteria for quantitative light-ing. There is also considerableagreement for this area when itcomes to the objectives of light-ing design. The aim is to arriveat a functional lighting that willprovide the optimum visual con-ditions for the activity in question be it work, leisure activities orsimply moving through the space.In contrast to the proponents

of quantitative lighting design,Lam objects to a uniform lightingthat is simply designed to suitwhatever is the most difficultvisual task. Instead, he proposes a

differentiated analysis of all thevisual tasks that arise, an analysisconducted according to location,type and frequency.

Biological needs

Lam sees the second complexof his system, i.e. the biologicalneeds, as being more essential.The biological needs sum upthe psychological demands thatare placed on a visual environ-ment and are applicable in everycontext. Whereas activity needsresult from a conscious involve-ment with the surroundings andare aimed at the functionality ofa visual environment, biologicalneeds largely concern uncon-scious requirements which arefundamental for evaluating asituation emotionally. They areconcerned with the feeling ofwellbeing in a visual environ-ment. The starting point for Lamsdefinition is the fact that ourattention is only dedicated to onespecific visual task in momentsof utmost concentration. Ourvisual attention almost alwayswidens to observe our entire sur-roundings. This allows changes

in the environment to be perceived

immediately and behaviour to beadapted to the altered situationwithout delay. The emotionalevaluation of a visual environmentdepends not least on whether thatenvironment clearly presents therequired information or whether itconceals it from the observer.


William Lam

OrientationOf all the fundamental psycho-logical demands placed on avisual environment, Lam ranks theneed for clear orientation as par-amount. Orientation can be ini-tially understood in spatial termshere. In which case, it would thenrelate to how discernable desti-nations and routes are and tothe spatial location of entrances,exits and other specific facilitieswithin the environment, e.g. areception desk or the individualareas of a department store. Butorientation also concerns infor-mation on further aspects of thesurroundings, such as the time ofday, the weather or what is goingon in that area. If this informa-tion is missing, as may be the casein closed spaces in departmentstores or in the corridors of large

buildings, then the environment isperceived as unnatural and evenoppressive. It is only by leavingthe building that we can catch upwith the information deficit.

Orientation Time of day

Weather Surroundings


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The majority of the informationthat we receive about the worldaround us comes through oureyes. Light is not only an essentialprerequisite, it is the medium bywhich we are able to see. Throughits intensity, the way it is distrib-uted and through its properties,light creates specific conditionswhich can influence our percep-tion. Lighting design is, in fact,

the planning of our visual envi-ronment. Good lighting designaims to create perceptual con-ditions which allow us to workeffectively and orient ourselvessafely while promoting a feelingof well-being in a particularenvironment. At the same timeit enhances the environment inan aesthetic sense. The physicalqualities of a lighting situationcan be calculated and measured.Ultimately, it is the actual effectthe lighting has on the user of aspace and his subjective percep-tion, that decides whether alighting concept is successful ornot.

E GuideBasics

Seeing and perception

Physiology of the eye Psychology of seeing Constancy

Perception of gestalt Objects of perception


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Edition: 20/09/2007 | Updated version at www.erco.com

When describing human percep-tion, it is inadequate to portraythe eye as an optical system. Theprocess of perception is not amatter of how an image of ourenvironment is transferred to theretina, but how the image isinterpreted and how we dif-ferentiate between objects withconstant properties in a changingenvironment.

E GuideBasics | Seeing and perception

Physiology of the eye

Optical system Receptors Adaptation


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Eye and camera The process of perception isfrequently explained by compar-ing the eye with a camera. In thecase of the camera, an adjust-able system of lenses projects

the reversed image of an objectonto a film. The amount of lightis controlled by a diaphragm.After developing the film andreversing the image during theenlarging process, a visible, two-dimensional image of the objectbecomes apparent. Similarly, inthe eye, a reversed image is pro-jected onto the retina of the eyevia a deformable lens. The iristakes on the function of the dia-phragm, the light-sensitive retinathe role of the film. The imageis then transported via the opticnerve from the retina to the brain,where it is adapted in the visual

cortex and made available to theconscious mind.In regard to the eye, however,there are considerable differ-ences between what is actuallyperceived and the image on theretina. The image is spatiallydistorted through its projectiononto the curved surface of theretina. Through chromatic aber-

E

Perspective

GuideBasics | Seeing and perception | Physiology of the eye

Optical system

Spherical aberration. Projectedimages are distorted due to thecurvature of the retina.

If we perceive objects that arearranged within a space, theperspectives of the images pro-duced on the retina are distorted.A square perceived at an angle,for example, will produce a trap-ezoidal image on the retina. Thisimage may, however, also havebeen produced by a trapezoidalsurface viewed front on. The onlything that is perceived is onesingle shape the square thatthis image has actually produced.This perception of a square shaperemains consistent, even if theviewer or object move, althoughthe shape of the image projectedon the retina is constantly chang-ing due to the changing perspec-tive.

Chromatic aberration. Images areblurred due to the various degreesof refraction of spectral colours.

Perceptual constancy: percep-tion of a shape in spite of thefact that the image on the retina

is changing with the changingperspective.

ration light of various wave-lengths is refracted to varyingdegrees, which produces colouredrings around the objects viewed.These defects, however, are elimi-

nated when the image is beingprocessed in the brain.


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E GuideBasics | Seeing and perception | Physiology of the eye

Receptors

Receptors There are two different types ofreceptor: the rods and the cones,which are not distributed evenlyover the retina. At one point, theso-called blind spot, there are

no receptors at all, as this is thepoint at which optic nerves enterthe retina.

Receptor density An area of the retina called thefovea is the focal point of thelens. In this area, the concen-tration of the cones is greatest,whereas the density of the conesreduces rapidly outwards to theperiphery. Here we find the great-est concentration of rods, which

do not exist in the fovea.

The older of these two systems,from an evolutionary point ofview, is the one consisting of rods.The special attributes of this sys-

tem include high light-sensitivityand a great capacity for perceiv-ing movement over the entirefield of vision. On the other hand,rods do not allow us to perceivecolour; contours are not sharpand it is not possible to concen-trate on objects, i.e. to studyitems clearly even if they are in

Rods

Number N of rods and cones onthe retina in relation to the angleof sight

the centre of our field of vision.The rod system is extremely sen-sitive and is activated when theilluminance level is less than 1 lux.

Our night vision features, particu-larly the fact that colour is notevident, contours are blurred andpoorly lit items in our peripheralfield of vision are more visible can be explained by the proper-ties of the rod system.

The cones form a system withvery different properties. This isa system which we require to seethings under higher luminousintensities, i.e. under daylight orelectric light. The cone systemhas lower light-sensitivity and isconcentrated in the central areain and around the fovea. It allowsus to see colours and sharpercontours of the objects on whichwe focus, i.e. whose image fallsin the fovea area. In contrast torod vision, we do not perceive theentire field of vision uniformly;the main area of perception is in

the central area. The peripheralfield of vision is also significant,if interesting phenomena areperceived in that area; in thatcase our attention is automati-

Cones cally drawn to these points. Thisis then received as an image onthe fovea to be examined moreclosely. Apart from noticing sud-den movement, striking coloursand patterns, the main reasonfor us to change our direction ofview is the presence of high lumi-nances our eyes and attentionare attracted by bright light.

Relative spectral luminous effi-ciency of rods V and cones V inrelation to the wavelength

Spectral colour sensitivity of thecones in relation to the wave-length


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E GuideBasics | Seeing and perception | Physiology of the eye

Adaptation

Day and night One of the most remarkableproperties of the eye is its abil-ity to adapt to different lightingconditions. We can perceive theworld around us by moonlight or

sunlight, although there is a dif-ference of a factor of 100,000 inthe illuminance. The extent oftasks the eye is capable of per-forming is extremely wide a

Luminance This ability to adapt to the illumi-nance is only influenced to a verysmall extent by the pupil. Adap-tation is performed to a largedegree by the retina. The rod andcone system responds to differ-ent levels of light intensity. Therod system comes into effect inrelation to night vision (scotopicvision), the cones allow us to seeduring the daytime (photopic

vision) and both receptor systemsare activated in the transitiontimes of dawn and dusk (mesopicvision).Although vision is therefore pos-sible over an extremely wide areaof luminances, there are clearlystrict limits with regard to con-trast perception in each individuallighting situation. The reason forthis lies in the fact that the eyecannot cover the entire range ofpossible luminances at one and

Adapting from dark to light situ-ations occurs relatively rapidly,whereas adapting from light todarkness requires a considerablylonger time. A good exampleof this is how bright we find itoutside having come out of adark cinema auditorium duringthe daytime or the transitoryperiod of night blindness weexperience when entering a verydark room. Both the fact thatcontrast in luminance can only

Adaptation time

Typical illuminances E and

luminances L under daylight andelectric lighting.

be accommodated by the eyewithin a certain range and thefact that it takes time to adapt toa new level of lighting, or bright-ness, have an impact on lightingdesign. For that reason lightingdesign requires, for instance, thepurposeful planning of differentluminance levels within a spaceor deciding on the adaptation oflighting levels in adjacent spaces.

the same time. The eye adapts tocover one narrow range in whichdifferentiated perception is pos-sible. Objects that possess toohigh a luminance for a particularlevel of adaptation cause glare,that is to say, they appear to beextremely bright. Objects of lowluminance, on the other hand,appear to be too dark.

faintly glowing star in the nightsky can be perceived, although itonly produces an illuminance of10-12 lux on the eye.

Luminance range L of rod vision(1), mesopic vision (2) and conevision (3). Luminances (4) andpreferred luminances (5) in inte-rior spaces. Absolute threshold ofvision (6) and threshold of abso-lute glare (7).)


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Psychology of seeing

To understand what visual percep-tion is all about, it is not so muchthe transport of visual informa-tion that is of significance. It israther the process involved in theinterpretation of this information,the creation of visual impressions.The question that arises is whetherour ability to perceive the worldaround us is innate or the resultof a learning process. Another

point to be considered is whethersensory impressions from outsidealone are responsible for theperceived image or whether thebrain translates these stimuli intoa perceivable image through theapplication of its own principlesof order. There is no clear answerto this question. Perceptual psy-chology is divided on this point.

Contour Overall shape Colour


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E GuideBasics | Seeing and perception | Psychology of seeing

Contour Experience, and the expectationslinked with it, may be so strongthat missing elements of a shapeare perceived as complete or indi-vidual details amended to enable

the object to meet our expecta-tions. The perception of a shapewith missing contours is simplybased on shadow formation.

Overall shape Experience leads us to recognise

an overall shape by being able toidentify essential details.

Colour This picture illustrates how acolour is matched to the respec-tive pattern perceived. The colourof the central grey point adjustsitself to the black or white colourin the perceived pattern.


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Constancy

Fixed objects produce retinalimages of varying shapes, sizesand brightness. Due to changesin lighting, distance or perspec-tive, this indicates that mecha-nisms must exist to identify theseobjects and their properties and toperceive them as being constant.There is no single, simple explana-tion for the way perception works.Optical illusions provide an oppor-

tunity to examine the perform-ance and objectives of perception.

Brightness Luminance gradient Three-dimensionality

Wall structure Beam of Light Perception of colour

Perspective Size


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E GuideBasics | Seeing and perception | Constancy

Brightness The fact that a medium greyarea will appear light grey if it isbordered in black, or dark grey ifit is bordered in white. This canbe explained by the fact that the

stimuli perceived are processeddirectly brightness is perceivedas a result of the lightness con-trast between the grey area andthe immediate surroundings.What we are considering here isa visual impression that is basedexclusively on sensory inputwhich is not influenced by anycriteria of order linked with ourintellectual processing of thisinformation.

The perception of brightnessof the grey field depends onthe environment in brightsurroundings, an identical greyappears darker than in dark sur-roundings.

Luminance gradient The continuous luminance gradi-

ent across the surface of the wallis interpreted as a property of thelighting. The wall reflectance fac-tor is assumed to be constant. Thegrey of the sharply framed pictureis interpreted as a material prop-erty, although the luminance isidentical to the luminance in thecorner of the room.

Three-dimensionality Changing luminance levels mayarise from the spatial form of theilluminated object; examples ofthis are the formation of typicalshadows on objects such as cubes,cylinders or spheres.

The spatial impression is deter-mined by the assumption thatlight comes from above.

By inverting the picture, the per-ception of elevation and depth isreversed.

The spatial form of an object canbe recognised by the gradient of

the shadows.


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Wall structure Irregular or uneven luminancescan result in confusing lightingsituations. This is evident, forexample, when luminous pat-terns created on the walls bear

no relation to the architecture.The observers attention is drawnto a luminous pattern that can-not be explained through theproperties of the wall, nor as animportant feature of the lighting.If luminance patterns are irregu-lar, they should, therefore, alwaysbe aligned with the architecture.

The lighting distribution on anunstructured wall becomes adominant feature.

Beam of Light The visible pool of light deter-mines whether it is perceived asbackground or as a disturbingshape. Light distribution that is

not aligned with the shape of thepicture is perceived as a disturb-ing pattern.

The same lighting distribution ona structured wall is interpreted asbackground and not perceived.

Light distribution that is notaligned with the architecturalstructure of the space is perceivedas disturbing patterns that do notrelate to the space.

Perception of colour The perception of colour, similarto the perception of brightness,is dependent on neighbouringcolours and the quality of thelighting. The necessity for us to beable to interpret colours is basedon the fact that colour appear-ances around us are constantlychanging. A colour is thereforeperceived as being constant bothwhen viewed in the bluish lightof an overcast sky or in warmerdirect sunlight colour photo-graphs taken under the sameconditions, however, show thedistinct colour shifts that wemust expect under the particulartype of light.


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Perspective Our misinterpretation of lines ofthe same length shows that theperceived size of an object doesnot depend on the size of theretina image alone, but that the

distance of the observer from theobject is significant. Vice versa,objects of known sizes are usedto judge distances or to recog-nise the size of adjacent objects.From daily experience we knowthat this mechanism is sufficientto allow us to perceive objectsand their size reliably. Therefore,a person seen a long way awayis not perceived as a dwarf anda house on the horizon not as asmall box. Only in extreme situa-tions does our perception deceiveus: looking out of an aeroplane,objects on the ground appear tobe tiny; the viewing of objects

that are considerably fartheraway, e.g. the moon, is muchmore difficult for us to handle.

In this case the perspective resultsin an optical illusion. The verticalline to the rear appears to belonger than the line of identicallength in the foreground.

Size To allow for the perception ofsize, we have a mechanism thatbalances the perspective distor-tion of objects. It guarantees that

the changing trapezoidal andellipsoidal forms in the retinaimage can be perceived spatiallyas being normal, rectangular orround objects by being aware ofthe angle at which the object isviewed.

Constancy with regard to per-ception of size. Due to the per-spective interpretation of thisillustration, the luminaires areall perceived as being the samesize in spite of the variations insize of the retina images.


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Perception of gestalt

Before a property can be attrib-uted to an object, the objectitself must be recognised, thatis to say, distinguished from itssurroundings. This process ofinterpretation has been usedto formulate laws accordingto which certain arrangementsare grouped together to formshapes, i.e. objects of percep-tion. These laws of gestalt are of

practical interest to the lightingdesigner. Every lighting installa-tion comprises an arrangementof luminaires on the ceiling,on the walls or in the space. Thisarrangement is not perceivedin isolation, but in forms orgroups in accordance with thelaws of gestalt. The architecturalsurroundings and the lightingeffects produced by the lumi-naires produce further patterns,which influence in our perceptionof the space.

Closed form Proximity Inside

Symmetry Shapes of equalwidth

Continuous line

Pure form Identity


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E GuideBasics | Seeing and perception | Perception of gestalt

Closed form An essential principle of the per-ception of gestalt is the tendencyto interpret closed forms as pureshapes.

Proximity Elements arranged close togetherare grouped according to thelaw of proximity and form a pureshape. The example on the leftdemonstrates that we first see acircle and then an arrangementof luminaires. The circles arearranged in such a strict order

that the imaginary linking linesbetween them is not straightlines, but forms a continuouscircle, not a polygon.Luminaires are grouped in pairs. Four points are grouped to form

a square.

From eight points on, a circle isformed.

Inside Shapes that are not completelyclosed can also be perceived as agestalt. A closed shape is alwaysseen as being on the inside ofthe linking line the formativeeffect therefore only works inone direction. This inner side isusually identical to the concave,surrounding side of the line thatencloses the shape. This in turnleads to a formative effect evenin the case of arcs or angles, mak-ing a pure shape visible inside theline, that is to say, in the partlyenclosed area. If this leads to aplausible interpretation of theinitial pattern, the effect of theinner side can be significant.

An arc makes a pure shape visibleon the inside of the line.


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Symmetry In regard to symmetry, the per-ception of a form as a pure shapeis based on simple, logical struc-ture. On the other hand morecomplex structures belonging to

the same pattern disappear intoan apparently continuous back-ground.

Shapes of equal width A similar result occurs in parallel

shapes of equal width. This is notstrictly a case of symmetry. Aprinciple of order and organisa-tion is, however, evident, allowingus to perceive a pure shape. Twoparallel lines show similarity.

Even without strict symmetry,it is possible to recognise a pureshape.

When two square luminaires areadded to the pattern of circulardownlights, the arrangement isperceived according to the lawof symmetry to form two groupsof five.

Continuous line A basic law of gestalt is to preferto perceive lines as steady con-tinuous curves or straight lines,and to avoid bends and kinks.Our preference to perceive con-tinuous lines is so great that itcan influence our overall inter-pretation of an image.

Law of gestalt relating to con-tinuous lines. The arrangement isinterpreted as two lines crossing.


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Pure form When it comes to two-dimensional shapes, the law ofthe continuous line conformswith the law of pure form. Inthis case, shapes are organised to

create figures that are as simpleand clearly arranged as possible.

Identity Besides spatial layout, the struc-

ture of the shapes themselves isalso responsible for their forma-tion into groups. The shapes inthe accompanying drawing arenot organised according to prox-imity or axial symmetry, but ingroups of identical shapes. Thisprinciple of identity also applieswhen the shapes in a group arenot absolutely identical but onlysimilar.Luminaires of the same type are

grouped together.

The downlight arrangement isgrouped into two lines accordingto the law of pure form.

The arrangement is interpreted astwo superimposed rectangles.


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Objects of perception

We are not however, consciousof every object that comes withinour field of vision. The way thefovea prefers to focus on small,changing scenes shows that theperception process purposefullyselects specific things to look at.This selection is inevitable, as thebrain is not capable of processingall the visual information in thefield of view. It also makes sense

because not all the informationthat exists in our environment isnecessarily relevant to us.

Activity Information Social


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E GuideBasics | Seeing and perception | Objects of perception

Activity The value of any particularinformation relates to the cur-rent activity of the observer.This activity may be work ormovement-related or any other

activity for which visual infor-mation is required. Lighting con-ditions under which the visualtask can be perceived to an opti-mum degree can be determinedfrom the above-mentioned spe-cific features. It is possible todefine ways of lighting whichwill be ideal for specific activities.

Visual field (1), preferred visual

field (2) and optimum field ofvision (3) of a person standingand sitting for vertical visualtasks

Preferred field of vision for

horizontal visual tasks. Preferredangle of view 25

Information There is another basic need forvisual information that goesbeyond the specific informationrequired for a particular activity.

This is not related to any particu-lar situation, it results from mansbiological need to understand theworld especially mans need tofeel safe. To evaluate danger, wemust be aware of the structureof the environment. This appliesto orientation, weather ,time ofday and information relating toother activities occurring in thearea. If this information is notavailable, e.g. in large, windowless

Social In regard to mans social needs the need for contact with otherpeople and the need for privatespace are somewhat contradic-tory and require careful balance.The focus on which visual infor-mation is required is determinedby the activities and basic biologi-cal needs. Areas likely to providesignificant information on theirown or by being highlighted - areperceived first. They attract ourattention. The information con-tent of a given object is respon-sible for its being selected as anobject of perception. Importantly,

buildings, the situation is oftenconsidered to be unnatural andoppressive.

the information content influ-ences the way in which an objectis perceived and evaluated.


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GuideDesigning with light

E

Light plays a central role in thedesign of a visual environment.The architecture, people andobjects are all made visible bythe lighting. Light influences ourwell-being, the aesthetic effectand the mood of a room or area.

Architectural lighting Planning process Practical planning

Visualising light


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E GuideDesigning with light

Architectural lighting

Lighting interiorspaces

Connecting spaces Illuminate objects

Design with colouredlight

It is light that first enables spatialperception. Above and beyondthis, our perception of architec-ture can also be influenced withlight: it expands and accentuatesrooms, creates links and deline-ates one area from another.


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Forming functionalzones

Defining spatialborders

Emphasising archi-tectural features

E GuideDesigning with light | Architectural lighting

Lighting interior spaces

Light can alter the appearanceof a room or area without physi-cally changing it. Light directsour view, influences perceptionand draws our attention to spe-cific details. Light can be usedto divide and interpret roomsin order to emphasise areas orestablish continuity between theinterior and exterior. Light distri-bution and illuminance have a

decisive influence on how archi-tecture is perceived.


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E GuideDesigning with light | Architectural lighting | Lighting interior spaces

Defining spatial borders

Floor illumination emphasisesobjects and pedestrian surfaces.Vertical spatial borders areemphasised by illuminating wallsurfaces. Uniform light distribu-

tion emphasises the wall as awhole, whereas accentuating,grazing light gives the wall struc-ture by adding patterns of light.Bright walls create a high levelof diffuse light in the room.

Vertical illumination is used to

shape the visual environment.Room surfaces can be differ-entiated using different levelsof illuminance to indicate theirimportance. Uniform illumina-tion of the surfaces emphasisesthem as an architectural feature.A decreasing level of brightnessacross a wall is not as effective asuniform wallwashing at definingroom surfaces. Lighting effectsusing grazing light emphasisethe surface textures and becomethe dominant feature. Indirectlighting of a ceiling creates dif-fuse light in the room with thelighting effect being influencedby the reflectance and colour ofits surface.

Observation

Conclusion

Applications

Projects:Conrad International Hotel,SingaporeLamy, HeidelbergEzeiza Airport, Buenos AiresLight and Building, Frankfurt

Wall bright Wall dark


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E GuideDesigning with light | Architectural lighting | Lighting interior spaces

Emphasising architectural features

The illumination of architecturaldetails draws attention away fromthe room as a whole towardsindividual components. Columnsappear as silhouettes in front of

an illuminated wall. Narrow-beam downlights emphasise theform of the columns. Grazinglight accentuates individual ele-ments or areas and brings outtheir form and surface texture.

Rooms can be given a visual

structure by illuminating thearchitectural features. By usingdifferent levels of illuminance,different parts of a room can beplaced in a visual hierarchy. Graz-ing light can cause highly three-dimensional features to caststrong shadows.

Observation

Conclusion

Applications

Projects:Tokyo International ForumInternational Hotel, SingaporePalacio de la Aljaferia, ZaragozaCatedral de Santa Ana, Las Palmas


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Inside lookinginside

Inside lookingoutside

Outside lookinginside

Outside lookingoutside


Connecting spaces

Combining rooms can createcomplex architectural patterns.Light interprets these in terms oftheir structure and orientation.Targeted lighting enables theviewer to look into an area andcreates spatial depth. The con-sideration of material qualitiesin combination with the correctilluminance, colour of light andlight distribution is an important

aspect in the design stage.


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E GuideDesigning with light | Architectural lighting | Connecting spaces

Inside looking inside

The bright rear wall gives theroom depth and accentuates thespatial perspective. Illuminatedobjects in the background achievea similar effect. If the emphasis

of the illuminance level is shiftedfrom the back to the front areaof the room, then the focus ofattention will also shift from thebackground to the foreground.

Observation

Light makes surfaces or objects

visible and allows them tobecome the focus of attention.Dark spatial zones cause spatiallimits to disappear and recedeinto the background. Differenti-ated spatial lighting can producea hierarchy of how spaces areperceived. Illuminating verticalsurfaces is of particular creativeimportance for the design sincea better effect is achieved as theresult of spatial perspective thanwhen illuminating horizontalsurfaces.

Conclusion

Applications

Projects:Museum Georg Schfer,SchweinfurtCatedral de Santa Ana, Las PalmasDZ Bank, BerlinGuggenheim Museum, Bilbao


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Inside looking outside

A high illuminance level in theinterior combined with a darkexterior creates a strong reflec-tion on the facade plane. Theinterior visually appears to double

in size from the exterior due tothe reflection. Objects in the out-door area are not recognisable.As the illuminance level in theinterior decreases and the lumi-nance in the exterior increases,the mirror effect is reduced andobjects on the exterior becomerecognisable.

Observation

Conclusion The reflection on the glass

becomes less as the luminancein front of the glass decreasesand the luminance behind theglass increases. Well shieldedluminaires in front of the glassplane cause less reflection. Lowerilluminance in the interior allowsbetter perception of the exterior.When directing luminaries onthe exterior, direct glare into theindoor area should be avoided.

Applications

Projects:Miho Museum, OsakaHarvey Nichols Restaurant,LondonPrivate home, New South WalesABN AMRO, Sydney


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Outside looking inside

The high illuminance level of day-light causes a strong reflectionon the glass surface. Objects inthe indoor area are not percept-able. As the illuminance level

in the outdoor area decreases,the reflection becomes less. Thisallows illuminated objects orsurfaces in the indoor area tobecome visible. The glass is nolonger perceptible.

Observation

Conclusion The reflection on the glass

becomes less as the luminance infront of the glass decreases andthe luminance behind the glassincreases. Luminaires in front ofthe glass that are well shieldedand integrated into architecturecause less reflection of them-selves. A low illuminance levelin the indoor area produces adeep spatial effect at night. Theillumination of objects in indoorareas such as shop windows requires very high illuminanceto make these objects visible dur-ing the day due to the high illu-minance level outside. Adjustingthe indoor lighting to the chang-ing daylight is recommendable.A higher illuminance level duringthe day and a low level in theevening reduces the contrast.Applications

Projects:Lamy, HeidelbergRitz-Carlton, SingaporeDat Backhus bakery, HamburgBlue Lagoon Spa, Reykjavik


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Outside looking outside

A bright rear wall lends depth tothe room and helps delineate theroom limits. Illuminated objects inthe background achieve a similareffect. If the emphasis of the

illuminance level is shifted fromthe back to the front area of theroom, then the focus of attentionwill also shift from the back-ground to the foreground.

Observation

Conclusion Light makes surfaces or objects

visible and brings them into theforeground. Dark zones of theroom make the room limits dis-appear and the effect of areasrecedes into the background. Dueto the low illuminance level atnight, the required illuminancesare less than for indoor lighting.

Applications

Projects:Hong Kong Convention andExhibition CentreMiho Museum, OsakaFederal Chancellery, BerlinPrivate home, Milan


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E

Light directs our view and focusesthe attention on details. The direc-tion of light, illuminance and thelight distribution all determinethe effect of an object in its sur-roundings.

GuideDesigning with light | Architectural lighting

Illuminate objects

Direction of light Vary the lightdistribution

Accentuate objects


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E

Directed light from the frontproduces a strong modelling abil-ity. Light from above causes theobject to cast strong shadows onitself. Light from behind creates

a silhouette. The steeper the inci-dent light, the more pronouncedthe shadow effect.

Observation

Conclusion If the light from the front is alsocoming slightly from one side, itgains a strong descriptive power.Light that is solely head-onhardly causes any shadow in thedirection of vision and the objectloses some of its 3-dimensionalappearance. Very steep incidentlight is suitable for objects having

a very shallow texture in order tomake them more 3-dimensional.

GuideDesigning with light | Architectural lighting | Illuminate objects

Direction of light


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Applications

Projects:Pinacoteca Vaticana, RomeGuggenheim Museum, BilbaoHermitage, St. PetersburgHermitage, St. Petersburg

Arrangement The steeper the incident light, themore pronounced the shadoweffect. Objects can be illuminatedwell when the direction of light isbetween 5 and 45 to the verti-

cal. The optimal direction of lightfor illuminating objects is at 30.This avoids strong reflected glareor undesirable shadows on peopleor objects.

E GuideDesigning with light | Architectural lighting | Illuminate objects

Direction of light

Highlighting is used for modellingobjects in:- museums- exhibitions

- salesrooms

Preferred luminaire groups- spotlights- floodlights


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Vary the light distribution

Narrow-beam spotlights accentu-ate the object and make it standout against the surroundings. Thebeam of light is stretched into anoval using a sculpture lens. Flood

lenses spread out the narrowbeam and create a soft brightnessgradient.

Observation

Conclusion The narrower the beam of lightcast on the object, the strongerthe effect. Sculpture lenses areparticularly suitable for project-ing light at objects over theirentire height. With their widelight beam, flood lenses illumi-nate the surroundings stronger

and represent the object in itsspatial relationship.

Spotlights

Sculpture lens

Flood lens

Applications

Projects:Bunkamura Museum of Art, TokyoMuseo del Prado, MadridVigeland Museum, NorwayHermitage, St. Petersburg

Highlighting is used for modellingobjects in:- museums- exhibitions- salesrooms

Preferred luminaire groups- spotlights with accessories


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Accentuate objects

The objects and the wall are givengeneral lighting by wallwashers.Beams from individual spotlightsadd emphasis to the objects.A higher brightness contrast

increases the level of accentua-tion.

Observation

Conclusion When the brightness contrastof the ambient surroundings tothe object is 1:2, a contrast canhardly be noticed. When the ratiois 1:5, a minimum brightnesscontrast is established betweenprimary and secondary points ofinterest. A contrast of 1:10 brings

out the difference very well. Abrightness contrast of 1:100detaches the object very stronglyfrom its ambient surroundingsbut an unintentional dissectionof the wall can arise.

1:1

1:5

1:10

Applications

Projects:Museo Ruiz de Luna Talavera,SpainGerman Architectural Museum,FrankfurtGuggenheim Museum, BilbaoMuseo Picasso, Barcelona

Highlighting of objects on walls isa practice used in:- museums- exhibitions- trade-fair stands- salesrooms


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Design with coloured light

Colour is a significant componentof visual perception. It cannotbe perceived without daylight orartificial lighting. The combina-tion of lamps and filters allowsa multitude of design possibili-ties for emphasising or alteringthe lighting effect of rooms andobjects with coloured light. Theterm colour of light covers bothwhite and coloured light. Warm

white, neutral white and daylightwhite are derived from the whitecolour of light. The coloured lightcovers the entire visible spectrum.

Colour Colour systems Colour of light

Colour mixing Colour rendition Colour effect

Colour contrast Ambient colours Coloured highlighting


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E GuideDesigning with light | Architectural lighting | Design with coloured light

Colour

The light colour refers to a colourwhich is emitted by a light source.The light colour is produced as aresult of the emitted spectrumof light. The type of light colour

is defined by hue, saturation andbrightness. Using filters producescoloured light. This enables thecolouration of rooms to be modi-fied without changing the roomsphysically. Mixing several lightcolours is referred to as additivecolour mixing.

Light colour

The body colour arises as a resultof the incident light and the spe-cific absorption properties of thesurface. Therefore, the tri-stimu-lus value of a body colour canonly be determined in combina-tion with the type of light withwhich it is illuminated. In additionto hue, brightness and saturation,the body colour of an object isalso defined by the reflectance.When illuminating coloured wallsor objects with coloured light, thereciprocal effect of light colourand body colour is paramount.This interplay is the basis of sub-tractive colour mixing. The chro-matic effects can be intensifiedor altered.

Body colour


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Colour systems

In the CIE standard colorimetricsystem, body colours and lightcolours are represented in acontinuous, two-dimensionaldiagram. The spectral constitu-

tion of light colours results fromthe type of light, while that ofbody colours results from thetype of light and the spectralreflectance or transmittance. Thedimension of brightness is leftunconsidered here; this meansthat only the hue and saturationof all colours can be determinedin the diagram. The coloured areais enclosed by a curve on whichthe chromaticity locations of thecompletely saturated spectral col-ours lie. At the centre of the areais the point of least saturation,which is designated as a whiteor uncoloured point. All levels of

saturation of one colour can nowbe found on the straight linesbetween the uncoloured pointand the chromaticity location inquestion. Similarly, all mixturesof two colours are likewise to befound on a straight line betweenthe two chromaticity locations inquestion. Complementary coloursare located opposite each otherin the CIE model and combine toform white.

CIE system

In the Munsell system, bodycolours are arranged accordingto the criteria of brightness,hue and saturation to producea complete sample catalogue inthe form of a three-dimensionalmatrix. Brightness here refers tothe reflectance of a body colour;the hue refers to the actual col-our, while the term saturationexpresses the degree of colora-tion, from the pure colour downto the uncoloured greyscale.Whereas a two-dimensional dia-gram is sufficient for colours oflight, a three-dimensional systemis required for body colours dueto reflectance.

Munsell system


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Colour of light: White light

The higher red component inwarm white light allows rooms toappear warmer than with neutralwhite light. The higher blue com-ponent in daylight white light

creates a cooler atmosphere.

Observation

On presentation lighting, makingspecific use of colours of lightallows luminous colours to beachieved on the objects beingilluminated. Daylight white lightis often used in office rooms toaugment the daylight.

Conclusion

Applications

Projects:Sony Center, BerlinGlass pavilion, Glass technicalcollege, RheinbachHong Kong and Shanghai BankERCO, Ldenscheid

Warm colours of light are pre-

ferred above all at lower illumi-nances and with directed light,whereas cold colours of light areaccepted at high illuminancesand diffuse illumination. Whitelight is described by specifyingthe colour temperature, colourrendition, chromaticity locationand spectrum. The white colourtemperature is divided into threemain groups: warm white, neutralwhite and daylight white. A goodcolour rendition with the lightingwill only produce a low colourdeviation. The chromaticity loca-tion identifies the colour withinthe CIE diagram.


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Colour of light: Coloured light

Compared to the primary coloursyellow, blue and red, the coloursamber and magenta appearweaker in their expressiveness.Yellow and red colours of light

create a warm atmosphere in aroom. Blue colours of light allowa room to give a cooler impres-sion.

Observation

In architectural lighting, colours

from the daylight spectrum arefelt to be natural: magenta (con-ditions of light at sunset), amber(atmospheric light at sunrise),night blue (clear night sky) andsky blue (light of the sky by day).For coloured light, the data con-cerning chromaticity locationand spectrum are important. Thechromaticity location is speci-fied by the co-ordinates in theCIE diagram, whereby a colour oflight can be formed by differentcolour spectra.

Conclusion

Applications

Projects:ERCO P3, LdenscheidZrich Insurance, Buenos AiresTeattri Ravintola, HelsinkiTeattri Ravintola, Helsinki

Coloured light is used for- exhibitions- trade-fair stands- salesrooms- event lighting


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Colour mixing: Light colour and body colour

Subtractive colour mixing occurswhen coloured surfaces areilluminated with coloured light.Mixing two of the subtractiveprimary colours magenta, cyan

and yellow, produces the addi-tive primary colours red, greenor blue. Warm body colours areemphasised by a warm whitecolour of light. Cold body coloursappear brighter and more satu-rated under cold neutral coloursof white light, especially daylightwhite.

Observation

The appearance of a body colour

can seem more saturated andbrighter when the lighting on itis of similar colour. Body coloursappear less saturated, or darker,when the coloured lighting is dis-similar. The actual appearance ofthe results of subtractive colourmixing depends on the spectralconstitution of the componentsbeing mixed.

Conclusion

Applications

Projects:Shop Colette, ParisGreater London AuthorityTeattri Ravintola, HelsinkiERCO Trade Fair, Hanover

In practice, when illuminatingcoloured surfaces, it is recom-mendable to perform lightingtests or calculations. The sameapplies to the use of colour filters.

Wall: BlueLight: Warm white

Wall: BlueLight: Blue

Wall: BlueLight: Magenta

Wall: BlueLight: Yellow


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Colour rendition

The quality of the reproductionof colours is termed colour rendi-tion. Linear spectra have a verygood colour rendition. Linearspectra only permit one single

colour to be perceived well. Mul-tiline spectra reproduce severalcolours of the relevant spectrumwell, but in the intermediate are-as the colour rendition is weaker.Blue and green colours appearcomparatively grey and mattunder warm white incandescentlight despite excellent colourrendition. However, these huesappear clear and bright underdaylight white light from fluo-rescent lamps despite poorercolour rendition. When renderingyellow and red hues, this phe-nomenon of respective weakeningand intensifying of the chromatic

effect is reversed.

Observation

Incandescent lamp

Continuous spectra lead to goodcolour rendition. Incandescentlamps or daylight have the colourrendition index Ra 100.

DaylightContinuous spectra lead to goodcolour rendition. Incandescentlamps or daylight have the colourrendition index Ra 100.


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Because the eye is able to adaptto light of the most differentcolour temperatures, the colourrendition must be determineddependent on the colour tem-

perature. Tungsten halogenlamps feature very good colourrendition. The rendition qualityof fluorescent lamps and metalhalide lamps ranges from goodto average. The degree of colourdistortion against a referencelight source is indicated using thecolour rendition index Ra or thecolour rendition grading system.The colour rendition index is onlyused for white colours of light.

Conclusion

Fluorescent lamp

Discharge lamps such as fluores-cent lamps or metal halide lampsfeature a multiline spectrum.Their colour rendition is thereforelower than Ra 100.


Colour rendition

Physics The same colours of light canproduce a different rendition ofa body colour due to differentspectral constitution. Continuous

spectra lead to a unifrom colourrendition. Linear spectra only cor-rectly render a very small colourrange. Multiline spectra are com-piled from different linear spectraand thus improve the colour ren-dition. The more spectra can bebound to one linear progression,the better the colour rendition.Incandescent lamps feature alinear spectrum, while dischargelamps have a multiline spectrum.

Linear spectrum Continuous spectrum Multiline spectrum

Applications

Very good colour rendition isimportant for- exhibitions

- trade-fair stands- salesrooms- offices- workstations


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Colour effect

- Red is the colour of fire andthe expression for power, warmthand energy. The colour has adominant effect. Where palered is concerned, the aspect of

warmth decreases while its light-ness increases.- Yellow is the lightest colour inthe colour wheel, but used in theforeground it does not have thesame energy as red.- Blue is the colour of the sky andis one of the cold colours whichgives an effect of depth. Darknavy blue has a rather melan-choly effect, whereas blue-greenemanates peace.- Green is the colour of vitality.Its nuances range from calmingto refreshing.- White is one of the non-coloursand is the polar opposite of black.

White stands for purity.- Black stands for darkness andappears sinister and negative.- Grey is one of the non-coloursand appears indifferent.

Observation

The effect of colours is explained

from the physiological point-of-view of actually seeing colour andthe psychological aspects of sen-sory perception. The lure of col-ours triggers associations and isinterpreted in the context of thesocial and cultural environment.The different hues belonging toa colour can, in turn, also haveother effects. The effect of indi-vidual colours can be increased byway of a colour contrast.

Conclusion

Applications

Projects:Saab City, LondonLight and Building 2000,FrankfurtRestaurant Aioli, ViennaTeattri Ravintola, Helsinki

Colour effects are particularlyimportant for- exhibitions- trade-fair stands- sales areas- restaurants


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Colour contrast

The seven colour contrasts origi-nated from the colour theory ofJohannes Itten. This approach isnot based on physical and chemi-cal properties of colours, but on

their subjective effects.

The primary colours yellow, redand blue produce the strongestcontrast. The colour contrastbecomes weaker with secondaryor tertiary colours or as the satu-ration decreases.

Colours themselves

The non-colours black and

white produce the strongestcontrast. Even with the propercolours, their effect is significant.A light colour next to a darkcolour has a stronger effect thannext to an equally light or lightercolour. The effect of hues can beintensified by greater differencesin brightness.

Light-dark

In the colour wheel, the warmcolours with red and yellow com-ponents are located opposite tothe cold blue hues. Green andmagenta form the neutral transi-tions. The effect of a predominantcolour can be increased whencombined with an accent fromthe opposite colour.

Cold-warm

WarmCold


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Colour contrast

The effect of the simultaneouscontrast has its origin in how theeye processes perception. Afterstaring at a colour for a long timeand then looking at a neutral

grey, the eye forms a simultane-ous contrast colour. Red leads toa green tinged grey shade. Greencauses a grey area with a redtinge to appear. Colours changetheir effect due to the influenceof the surrounding colours.

Simultaneous

The pairs of colours lying oppo-site in the colour wheel form thecomplementary contrast from aprimary colour and the secondary(mixed) colour made of the othertwo primary colours. Yellow-vio-let displays the largest light-darkcontrast, orange-blue the largestcold-warm contrast. Red-greenhave the same light intensity. Thecomplementary contrast causes

the brilliance of the colours toincrease.

Complementary


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Colour contrast

The quality contrast, or intensitycontrast, describes the distinctionbetween pure colours and murkycolours. Mixing pure colours withgrey shades makes the former

murky and dull, and the quality ofcolour purity is lost. Pure colourshave a dominating effect overmurky colours.

Quality

The quantity contrast refers to

the relationship of the size of onecoloured area with the next. Alarge coloured area with a smallarea in a contrast colour increasesthe chromatic effect of the maincolour.

Quantity


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Ambient colours

White light that is reflected by acoloured surface takes on the col-our of the surface and becomesthe predominant colour of lightfor the whole room. When light-

ing a coloured wall with colouredlight, this effect can be increased,reversed or inverted.

Observation

The colour of light in a room isinfluenced by the decoration ofthe room. In comparison to dif-fuse light, direct light increasesthe effect of the light when illu-minating a coloured surface. Theeffect of a body colour can beintensified by using coloured lightof a similar colour. Strong colourcontrasts appear brighter for thesame illuminance than a weaker

colour contrast. Lesser colourcontrasts can be perceived better

Conclusion under brighter lighting. Withinclosed rooms the effect is hardlyperceptible due to the phenom-enon of colour constancy.

Wall: YellowWhite light: Warm white

Wall: RedColoured light: Magenta

Wall: WhiteColoured light: Amber

Wall: YellowColoured light: Sky blue

Applications

Projects:Polygon Bar, LondonGreater London AuthorityTennispalatsi Cultural Museum,HelsinkiApropos Cln Concept Store,Cologne

In practice, when illuminatingcoloured surfaces, it is recom-mended that lighting tests orcalculations be carried out.

Coloured accent lighting isused for- exhibitions- trade-fair stands- sales areas


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Coloured highlighting

Coloured accent lighting andcoloured background lightingchanges the effect of objects inthe room. The colour saturationof the object increases in the

foreground when the backgroundbrightness is decreased. Bluecolours seem to recede into thebackground, while the chromaticeffect makes magenta come tothe fore.

Observation

Lighting effects can be intensifiedusing coloured light. Strong col-our contrasts increase the bright-ness contrasts. High brightnesscontrasts likewise increase thecolour contrasts. Natural overalleffects arise due to warm coloursof light and filter colours such asSkintone, magenta and amber,or due to cold colours of lightsuch as sky blue and night blue.

Conclusion

Wall: WhiteStele: Night blue

Wall: MagentaStele: White

Wall: AmberStele: Magenta

Wall: Sky blueStele: Amber

Applications

Projects:Museo de Bellas Artes, BilbaoZrich Insurance, Buenos AiresTeattri Ravintola, HelsinkiLight and Building 2002,Frankfurt

Coloured accent lighting isused for- exhibitions- trade-fair stands- sales areas


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GuideDesigning with light

Planning process

E

The planning process provides anoverview of the sequence of theindividual tasks in lighting design.This process is closely linked withthe planning procedure for anarchitectural design. The findingsof the analysis are firstly chan-nelled into the concept planningand are then finalised for imple-mentation in the design. In addi-tion, maintenance schedules are

a prerequisite for maintaining thequality of light on site.


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E GuideDesigning with light | Design practice

Project analysis

The basis for every lighting designconcept is an analysis of theproject; the tasks the lighting isexpected to fulfil, the conditionsand special features. A quantita-

tive design concept can to a largeextent follow the standards laiddown for a specific task. Stand-ards dictate the illuminance level,the degree of glare limitation, theluminous colour and colour ren-dering. When it comes to quali-tative planning, it is necessaryto gain as much information aspossible about the environmentto be illuminated, how it is used,who will use it and the style ofthe architecture.

A central aspect of project analy-sis is the question of how thespaces that are to be illuminatedare used; it is important to estab-lish what activity or activitiestake place in the environment,how often and how importantthey are. This comprehensiveanalysis of the task gives rise toa series of individual visual tasks,the characteristics of which must

in turn also be analysed. Twocriteria relating to a visual taskare the size and contrast of thedetails that have to be recordedor handled; there then followsthe question of whether colouror surface structure of the visualtask are significant, whethermovement and spatial arrange-ment have to be recognized orwhether reflected glare is likely tobe a problem. The position of thevisual task within the space andthe predominant direction of viewmay also become central issues.

Introduction

Utilisation of space


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E GuideDesigning with light | Design practice

Project analysis

From the point of view of archi-tecture and ambience, a buildingor space should be made visible,its characteristics accentuatedand its ambience underlined. Thisrequires detailed information onthe architecture and on the over-all architectural concept com-plete with the intended indoorand outdoor effect by day andnight, the use of daylight and the

permissible energy consumption.This also includes informationon materials, reflectance and thecolour scheme. In Architecturallighting its not primarily aboutthe lighting which emphasisesthe building structures and char-acteristic features for a particularperspective, but rather how tocreate the required aestheticeffect in a space. The questionof the building shape, of spatialshape, modules and rhythmicalpatterns, which can be identifiedand expressed by light and lumi-naires constitutes the centralissue.

Architecture and ambience

Psychological requirements The psychological requirementsinclude perception of the widersurroundings to establish thetime of day, the weather and tofacilitate spatial orientation. In

large buildings frequented by dif-ferent users, the need for visualguidance can become a impor-tant issue. An orderly and clearlystructured environment contrib-utes to the general feeling ofwellbeing. Differentiated lightingcan provide spatial delineationfor areas with separate functions.Where there are conversationalzones within larger areas, it maymake sense to create privateareas by using suitable lighting.


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E

Lighting concepts list the proper-ties that lighting should possess.They give no exact informationabout the choice of lamps orluminaires or about their arrange-

ment. Project analysis provideslighting quality guidelines givinginformation about the individualforms of lighting. These relateto the quantity and variousquality features of light, andalso gives the degree of spatialand temporal differentiation. Apractical design concept requiresconsultation with the othertrades involved. It must meetthe specifications of the relevantstandards and take both invest-ment costs and running costsinto consideration. The challengeof a qualitative lighting design isto develop a design concept that

combines the technical and aes-thetic requirements of complexguidelines. A concept that deliv-ers the required performance witha commensurate level of techni-cal expertise and the highest levelof artistic clarity will produce themost convincing solution.

In the design phase, decisionsare made regarding the lampsand luminaires to be used, thearrangement and installation ofthe luminaires and any requiredcontrol gear and control devices.This also allows a reliable calcula-tion of illuminance and costs.No strict process can be set out,nor even one describing gener-ally routine design stages. Thedecision regarding lamp type canbe made at the beginning of aproject or left until an advancedplanning stage; luminaire arrange-ment can be determined by thechoice of a certain luminaire orcould be the criteria for luminaireselection. Lighting design shouldbe seen as a cyclical process inwhich developed solutions arerepeatedly compared to thestated requirements.

Design

GuideDesigning with light | Design practice

Lighting concept


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E

A wide range of luminaire types e. g. spotlights and light struc-tures - are exclusively designedto be installed as additive ele-ments. They may be mounted

on track or lighting structures,suspended from the ceiling(pendant luminaires) or surfacemounted onto the wall or ceil-ing. The range of downlights andlouvered luminaires available isso vast and their designs differsubstantially, which means thatnumerous modes of installationare required. In the case of wallor floor mounting the luminairesmay be surface-mounted orrecessed into the fabric of thebuilding. Ceiling mounting allowsa variety of possibilities: recessedmounting, surfaced mounting orpendant mounting. The Installa-

tion Instructions for the lumi-naires explain the installationand maintenance of the lumi-naires in detail.

The maintenance of a lightinginstallation generally compriseslamp replacement and thecleaning of the luminaires, and

possibly also re-adjustment orrealignment of spotlights andmovable luminaires. The mainobjective of maintenance is toensure that the planned illumi-nance is maintained, i. e. to limitthe unavoidable reduction ofluminous flux of a lighting instal-lation. The reasons for the reduc-tion in luminous flux may bedefective lamps and the gradualloss of luminous flux by the lampsor a decrease in light output dueto soiling of the reflectors orattachments. In order to avoida reduction in luminous fluxall lamps must be replaced andluminaires cleaned at regularintervals. Qualitative aspects mayalso be decisive for maintenance.When one lamp in a geometricalarrangement of luminaires failsit may have a detrimental effecton the overall illuminance in thespace. The task of the lightingdesigner is to draw up a main-tenance plan that meets therequirements of the given situa-tion and includes the necessaryinformative literature.

Maintenance

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Installation


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E GuideDesigning with light

Practical planning

Having completed the projectanalysis and developed a lightingconcept, the next phase entailspractical planning: decisionsregarding the lamps and lumi-naires to be used, the arrange-ment and installation of the lumi-naires. A detailed design can bedeveloped from a concept basedprimarily on lighting qualities.

Choice of lamps

Mounting

Luminaire selection

Maintenance

Luminaire arrange-ment


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E GuideDesigning with light | Practical planning

Choice of lamps

Selecting the right lamp for theluminaire depends on the actuallighting requirements. For thesuccessful implementation ofa lighting concept the physicalaspects, such as colour rendition,and the functional criteria aredecisive.Modelling Colour rendition Light colour

Luminous flux Economy Radiant emission


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Choice of lamps

Modelling and brilliance areeffects produced by directedlight. Compact light sources suchas low-voltage halogen lamps ormetal halide lamps are a prereq-

uisite for this. When illuminatingsculptures, presenting merchan-dise or lighting interestinglytextured surfaces, the modellingability and brilliance are of cen-tral importance.

The colour rendition of the lightsource is determined by theactual lamp spectrum. A continu-ous spectrum ensures the optimal

colour rendition. Linear or bandspectra generally worsen the col-our rendition. A very good colourrendition quality is produced byincandescent lamps includingtungsten halogen lamps.

Colour rendition

The light colour of a lampdepends on the spectral distri-bution of the emitted light. Inpractice, the light colours arecategorised into warm white,neutral white and daylight white.Warm white lamps emphasise thered and yellow spectral range,whereas blue and green, i.e. coolcolours, are accentuated underdaylight white light.

Light colour

Modelling

Ranges of the colour renditionindex Ra for different lamp types

Ranges of colour temperature TFfor different lamp types


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Luminaire selection

The choice of light sources out-lines the technical qualities ofthe lighting design concept andthe limits to the lighting qualitiesthat can be achieved. The light-ing effects that can be obtainedwithin this range depend on thechoice of luminaires in which thelamps are to be used. The choiceof lamp and luminaire is there-fore closely related. Opting for a

particular light source will reducethe choice of luminaire, and viceversa, the choice of luminaire willrestrict the choice of lamp.

Light distribution Luminous colour Methods of mounting

Luminance Illuminance Safety requirements


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E GuideDesigning with light | Practical planning | Luminaire selection

Light distribution

Uniform general lighting is astandard lighting concept. Forgeneral lighting, wide-beamluminaires such as downlightsand light structures are suitable.

Uniform lighting can also beachieved by indirect illumination.However, a lighting concept thataims solely to create isolatedlighting accents is the exception.Often, accent lighting will containgeneral lighting components toallow the viewer to perceive thespatial arrangement of the illumi-nated objects. Spill light from theaccentuated areas is frequentlysufficient to provide adequateambient lighting. Luminaires thatemit a directed, narrow beamcan be used for accent lighting.Adjustable spotlights and direc-tional luminaires are ideal.

general differentiated

Uniform general lighting usingwide-beamed illumination

Differentiated lighting usingnarrow-beam light fromspotlights


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E GuideDesigning with light | Practical planning | Luminaire selection

Light distribution

The decision for narrow orwide light distribution is closelyconnected with the concept ofgeneral or differentiated light-ing. Luminaires with a beam

angle of less than 20 are knownas spotlights and above 20 asfloodlights. With downlights, thecut-off angle also gives an indi-cation of the width of the lightdistribution. Wide light distribu-tion creates a higher proportionof vertical illuminance.

wide narrow

Wide light distribution forindirect lighting

Narrow-beam light for high-lighting


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Symmetrical light distributionis used for providing even light-ing. The light distribution can bewide for downlights used for thegeneral lighting of horizontal sur-

faces. With spotlights, the lightdistribution is narrow beamed toprovide highlighting. Luminaire

en erco guide

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