Studiu de caz privind designul si calitatea iluminatului

1. Introducere2. Aspecte psihologice influentate de iluminat3. Factori fizici care influenteaza calitatea iuminatului 4. Conceptele iluminatului si metode care conduc la un design al iluminatului bun5. Concluzii

1. Introducere

Cum iluminam un magazin cu jucarii pentru copii? Dar o sala de conferinte? Ce ne face sa ne simtem bine sis a revenim in acel loc? De ce nu vrem sa petrecem timp intr-un anumita zona iluminata a incaperii?

Cred ca exista multi factori care influenteaza raspunsul de mai sus, ca tine de psihologie, designul iluminatului, starea sau tehnica folosita in realizarea iluminatului ambiental. Probabil unele din intrbarile de mai sus se regasesc in gusturile fiecaruia dar studiu si experienta poate sa ne ajute de a raspunde la anumite intrebari de mai sus.

se spune ca lumina este a 4 dimensiune a arhitecturii .Cred ca cel mai important in realizarea iluminatului residential este dat de raspunsul la intrebarea ‘’ ce ne face sa ne simtim ca acasa’’ . Daca intrebarea ofera solutii specialistiilor din iluminat atunci nu doar estetica tine de iluminat ci si procese psihologice. Bazele de informatii in literature de specialitate privind iluminatul provin din documente stintifice si proiecte practice.

2. Aspecte psihologice influentate de iluminat

Oamenii care lucreaza la birou sustin constant ca iluminatul este un factor important alaturi de mobilier si design. Este foarte greu de obtinut rezultate din experimente pe esantioane de oameni care sa ofere informatii asupra unui tipar eficient de iluminat datorita …. Natura omului contine effecte fundamentale psihologice care se regasesc si la calitatea iluminatului – parformanta la birou, confort si starea de bine. Aceste pot varia din cauza unor caracterisctici ale iluminatului ca si : luminance/illuminance , uniformitate, stralucirea, flicker, spectral power distribution. De exemplu psihologii sustin ca controlul poate modera reactiile la stress iar lipsa acestuia duce la sentimente de neajutorare. Exista cercetari care afirma ca un numar procentaj ridicat de oameni prefer sa aibe control asupra iluminatului din birou dar interesant este faptul ca 2 cercetatori Veitch and Gifford in urma unui experiment au observant ca persoanele care au avut control asupra iluminatului au avut performante la munca mai slabe si creativitate mai scazuta decat participant la test care nu au avut control asupra iluminatului. Totusi existent unui control nu a realizat diferente mari de performanta. Intr-un experiment separate Nelson et al. a descoperitca cresterea iluminarii de la 100 la 300 lx oamenii s-au observant (antonim) la 3 stari psihologice :concentrare, starea de bine si activitatea) iar la femei s-au imbunatatit iar In aceeasi tema

Leslie and Hertleb in urma unui experiment sugereaza faptul ca exista diferente intre preferintele dintre sexe.

Daca vine vorba de manipularea afectiva cauzata de impactul iluminatului ambiental in urama unui experiment reisese ca Reflexul de tresărire este un factor important si poate fi definit ca "un val de mişcări flexoare care se răspândeşte cranio-caudal de-a lungul axei neuronale, care este determinat de un eveniment senzorial produs brusc la o anumită intensitate luminoasa"

Prezenta cercetare foloseşte psihofiziologia pentru a explora efectul iluminatului ambiental asupra amplitudinii reflexului de tresărire măsurat în timpul expunerii la imagini placate sau neplăcute . Rezultatele noastre sugerează că iluminatul ambiental poate juca un rol important în modularea răspunsului psihologic afectiv la diferite tipuri de conţinut şi intensitate a imaginilor. Acest lucru a fost evident pentru amplitudinea măsurată a reflexului de tresărire pentru imaginile prezentate în condiţii de "lumină".". Pe de altă parte, nu s-au înregistrat diferenţe în amplitudinea tresăririi între expunerile la cele trei tipuri diferite de imagini atunci când examinarea tresăririi a fost facută într-un mediu întunecat. În plus, întunericul nu a făcut decât să potenţeze răspunsul RT la imagini plăcute şi neutre, dar nu a avut niciun efect modulator asupra imaginilor neplăcute. Dupa cum se poate observa în Figura 2, în condiţii de "întuneric" răspunsul psihologic este aproape identic pentru toate cele trei tipuri de imagini. Acest lucru sugerează că un mediu întunecat ar putea să nu aibe nicio influenţă asupra modului în care sunt procesate imaginile neplăcute, dar un mediu de vizionare întunecat duce la creşterea activării motivaţionale aversive pentru imagini neutre şi plăcute.

Environmental appraisal and affect are interconnected theories. One, appraisal, analyzes the meanings we extract from scenes we view. The other concerns our emotional response to them and predicts desirable behavioral responses if that response is positive. Both are in embryonic states of development. In particular, we lack replicable knowledge about the structure of interpretations of luminous conditions -- how many dimensions are there, and what are they?

Varsta isi spune si ea cuvantul cand vine vorba de preferinta privind ilumintul. Cei mai invarsta prezinta cu covingere spre un iluminat puternic.

Este necesar sa tinem cont si de mecanismele psihologice care produc urmari de comportament ca raspuns la conditiile de iluminat.Cand vom intelege de ce anumite conditii ale iluminatului produc un comportament dorit atunci vom putea…..

Oamenii folosesc distributiile luminoase ca baze de a judeca appeareance spatiului, memoria afectiva sau preferinte.

Interactiunea sociala si comunicarea

S-a constatat ca o comunicare de durata mai mare dar si mai zgomotoasa este datorata unui nivel de iluminare ridicat. Sanders, Gustanski, and Lawton (1974) observed this effect in naturally-occurring groups in a university corridor (over the range 10-270 lx). Groups of female university students conversing about fictional job candidates were louder, however, under low illuminance (400 lx) than high illuminance (1274 lx) (Veitch & Kaye, 1988). Veitch and Kaye speculated

that the reason for the difference in results lies in different expectations for the settings involved. This hypothesis isconsisted with Gifford’s (1988) finding that intimate communication was greater with a homelike decor than a classroom decor. Gifford (1988) studied the quantity of general and intimate written communication in relation to illuminance and decor. He reported trends in which both types of communication were increased under higher illuminance (60 and 900 lx), and concluded that arousal theory can account for the outcome. The theory is that higher illuminance levels induce greater arousal and, in this case, more communication.

Biner (1991) demonstrated that 1650 lx illuminance increases general arousal in comparison to 30 lx; but Kaye (1988) found that lower illuminance was associated with increased self-reported arousal (500 vs 1200 lx).

Tabele si notatii ARTICOLSaunders (1969) found that illuminance ratios lower than 0.7 caused asubstantial increase in dissatisfaction, although the drop in satisfaction from 1.0 to 0.7 was small.Luminance ratios of 1:1 are considered optimal in North America, with 3:1 (i.e., task brighterthan surround) being acceptable (Rea, 1993). These values are nominally based on researchresults (Guth, 1970).

Biological and health effects. The role of light in the regulation of circadian rhythms iswell known (e.g., Hill, 1992). Light exposure suppresses melatonin secretion; melatonin inducessleep. In healthy subjects, exposure to monochromatic (509 nm) light overnight suppressesmelatonin secretion in a dose-dependent manner (Brainard et al., 1988). This knowledge has ledto the demonstration that bright light exposure can facilitate shift workers’ adjustment (Czeisler,Johnson, Duffy, Brown, Ronda, & Kronauer, 1990).Health and comfort. Fluorescent lamps have long been associated with complaints ofvisual discomfort and headache (cf. Stone, 1992). Putative causes of these effects include bothflicker rate and spectral power distribution (Wilkins, 1991, 1993).

3. Factori fizici care influenteaza calitatea iuminatului

Un factor important este cunoasterea cat mai mult a incaperii unde se va efectua planurile de iluminat. De exemplu uniformitatea este in stransa legatura cu inaltimea camerei in cazul iluminatului natural prin …….. . Avand aceeasi parametrii si crescand inaltimea tavanului lumina transmisa este distribuita pe o suprafata mai mare la nivelul pardoselii asta in cazul iluminarii uniforme . In acceasi tema se afla si culoarea care este redata peretiilor sau tavanului.De accea pentru a obtine o incapere cat mai luminoasa se poate opta la o culoare deschisa a tavanului si culorile saturate pe suprafetele secundare sau mai mici unde distributia luminii nu este asa importanta.

Este important de stiut ca un nivel de iluminare ridicat poate atrage atentia sic a acest lucru poate fi folosit eficient in spatii ca si clasele pentru studenti sau elevi desi in aceeasi directive iluminatul spatiului de lucru nu are acceasi effect.

Simulation and realityOften, the quality of a simulation is judged by its proximity to reality and the question is asked as to whether the rendering is correct or no more than a photorealistic representation. The criterion of physically correct data refers to the numerical values provided by the quantitative simulation. Screen displays or colour printouts can never give the same impression as the actual environment. A photographer controls the incident light by opening or closing the aperture and the same creative approach is taken in the production of a rendering. A further limitation is the range of contrasts on the output media. None of the following can correctly reproduce the luminance contrast which will be seen in reality: colour printout, screen display or the projected image of a beamer.A photorealistic impression of a qualitative simulation can provide a far more authentic representation of the anticipated lighting effect, such as the progression of light and shadow or reflections off surfaces.

4. Conceptele iluminatului si metode care conduc la un design al iluminatului bun

In ciuda variabilitatii preferintelor individuale si in ciuda diferentelor culturale se pare ca exista un lucru comun care poate fi aplicat si anume nivelurile de iluminat mai mari sunt preferate.\

Preferences for illuminance levels are generally higher than the recommended levels.Despite known cultural differences in illuminance preference (Belcher, 1985), this is trueregardless of culture. For example, Leslie and Hartleb (1990) found that American universitystudents chose an average illuminance of 1557 lx for a reading task, which is 1000 lx higher thanthe recommended level for such a task and age group (Rea, 1993). Similarly, 1500 lx was ratedmost highly for clerical office work at a time when the American standard was 1000 lx (Barnaby,1980/Hughes & McNelis, 1978).

Begemann, Aarts, and Tenner (1994) (see Aarts, 1994, for a detailed report) found thatDutch office workers added an average of 800 lx of artificial light, regardless of daylight orweather conditions; the Dutch illuminance standard for offices is 500 lx. British office workerswere more satisfied with a horizontal illuminance of 800 lx than with the then-standard 400 lx(Saunders, 1969). Boyce (1973) also reported that higher illuminances were preferred by allparticipants in a British sample, regardless of their age, over the range 160-1600 lx taskilluminance. One exception to this pattern is a pilot study involving French office workers, inwhich illuminance preferences were consistent with recommended practice (Berrutto, Avouac-Bastie, Fontoynont, & Belcher, 1994).

Experienta ne-a invatat ca daca aceste concepte sunt bine proportionate va rezulta un iluminat de success. ( trebuie gasit un nume la play of brilliants)

Atat folosirea corpurilor de iluminat si a skylights exista riscul de a aparea un discomfort iar atentia trebuie acordata ( raspunsul ) spre evitarea folosirii luminii excesive spre campul visual al oxupantului si evitarea relexiei luminii pe suprafata de lucru

Lumina ambientala, iluminatul de accent sau iluminatul scenic sunt principalele elemente ale iluminatul calitativ. Toate acestea au fost combinate de designer Richard Kelly tinand cont de perceptia psihologica si iluminatul teatral ( invers sens propozitii)

Se pare ca iluminatul pe suprafetele vertical ar fi cheia spre satisfactia ocupantului in spatiu iluminat de aceea oamenii prefera peretii mai iluminati decat cei intunecati iar o posibila explicatie ar fi imaginarea ferestrelor pe acestia. Acum o intrebare apare si accea este, cat de ridicat ar trebui sa fie aceste suprafete vertical? Quality of the Visual Enviroment (QVE) impreuna cu Iluminating Engineering Society of North America si International Association of Lighting Designers au condus o serie de studii pilot pentru preferintele in conditii de iluminat diferite. In toate cele trei experimente pilot a

Perceptia noastra despre arhitectura poate fi influentata de lumina prin definirea zonelor si a spatiilor dintre acestea , legaturi intre spatii ……..

Faptul ca un o zona in gri mediu va aparea ca un gri luminous daca este incadrat in negru si un gri intunecat daca este incadrat in alb. Acest lucru este perceput ca impresie vizuala in care stimulii proceseaza contrastul dintre gri si zonele alaturate astfel.

Luminance Distribution and Illuminance Uniformity across RoomsLighting designers may consider luminance distribution, the pattern of light and darkacross vertical and horizontal surfaces, to be synonymous with lighting quality. “Hide thesource, light the walls; don’t cause glare problems” is how one well-known designer summarisedhis views on lighting quality for offices at a seminar on office lighting (M. Kohn, May 3, 1996,Ottawa, Canada).

Recent exista un mod interesant in care designer in iluminat (executa ) proiectele si anume prin rapoarte dintre diferite zone ale spatiului , de exemplu in intre background si task, sau intre pareti si tavan iar prin anumite experimente acestia au obtinut anumite rezultate care binenteles pot varia mult datorita psihologiei si modului de perceptive.

Yorks and Ginthner found that visitors to a mock office preferred to have a bright wall in front of the desk, and tended to move farther into the room towards the brighter wall (although this finding is questionable, given the small sample size and unusual data analysis).102 Tregenza et al. found that preferred wall:desk illuminance ratios were different for the front, rear, left and right walls.83 Their participants preferred a brighter wall behind the desk.

The luminance distribution between the task and its distant background, and horizontal illuminance ratiosacross a space, have become more important with the advent of task/ambient lighting designs. Bean and Hopkins found that the highest percentage of raters were satisfied with task lighting when the illuminances for the task and background (ambient) lighting were equal.99 They recommended that task:background illuminance ratios be close to 1:1. However, McKennan and Parry found that nonuniform distributions can be acceptable.34 All the installations, both localized (directed from the ceiling to the desk) and local (task lamps) lighting, were rated as satisfactory, even though some of these systems produced illuminance ratios for desk surfaces and wall:task that were much lower than the recommended practice

Miller reported an informal experiment in which conference attendees rated their opinions of five scenes in simulated offices.3 The most-preferred scene had approximately equal amounts of lighting energy directed at the walls and working plane. The task illuminance of that scene was 387 lx and the ratio of maximum to minimum wall luminance was 3:1 (the range over all scenes was 2:1 to 4.5:1, and illuminance ranged from 108 to 646 lx).

This pilot study paved the way for a more detailed examination of ceiling and wall luminances in relation to acceptability judgments.97 In that study, for direct/indirect luminaires, higher desktop illuminance was preferred (range 300-700 lx) and ceiling:wall luminance ratios between 1:3 and 3:1 were preferred over the extremes of 1:5 and 5:1. For low-brightness recessed parabolic louvered luminaires, the participants preferred having some light on the walls: ceiling:wall luminance ratios of 1:3 and 1:5 were preferred over 1:1. In a re-analysis of the data combining all lighting systems, they found that the best predictor of acceptability judgments was the average of the wall and ceiling luminance, which they called volumetric brightness. Higher values predicted greater acceptability. In thatstudy, for direct/indirect luminaires, higher desktop illuminance was preferred (range 300-700 lx) and ceiling:wall luminance ratios between 1:3 and 3:1 were preferred over the extremes of 1:5 and 5:1. For low-brightness recessed parabolic louvered luminaires, the participants preferredhaving some light on the walls: ceiling:wall luminance ratios of 1:3 and 1:5 were preferred over1:1. The degree of acceptable nonuniformity remains undetermined. The relationship appears to depend on the level of overall illuminance. Slater et al. (1993) found thatilluminance ratios as low as 0.6 between desks in an open office were acceptable when roomilluminance was high (730 lx), but the lower limit of acceptable illuminance uniformity betweendesks for lower illuminance (350 lx) was 0.7. This suggests that at low illuminance, people wantmore uniformity.

GlareGlare is to light as noise is to sound. Just as noise is unwanted acoustic energy, glare isunwanted luminous energy. Lighting professionals distinguish between two types of glare:disability glare and discomfort glare (Rea, 1993). Disability glare describes the effect ofscattered light, from luminaires or bright surfaces, when it reduces the contrast between a viewedobject and its background. Discomfort glare refers to the experience of physical symptomsassociated with viewing bright sources, either in the field of view or by reflection. Thus, onecould distinguish these two types of glare in terms of their behavioural effects: Disability glare isa visual performance effect, and discomfort glare is a comfort and health effect. Each isassociated with particular glare sources. Systematic attempts have been made to developpredictive models for these behavioural outcomes on the basis of luminous conditions.

O sculptura poate fi iluminata in diferite moduri oferind impresii dupa fiecare caz….? Exista combinatia dintre un iluminat uniform,lumina directionata si lumina din spate care ar parea situatia cea mai atragatoare si complete . Daca sculptura este iluminata doar cu un spot formandu-se o lumina directionala pe aceasta se vor descoperii atat umbre cat si forme care vor iesi in evidenta. Daca se doreste obtinerea doar a formei sculpturii aceasta se foloste un iluminat de fundal , sculptura astfel va trece intr-un plan second.

Daca vine vorba de impresia psihologica a culorilor se cunoaste ca culorile calde dau senzatia de continuitate iar culorile reci o senzatie vizuala de ‘oprire’.

Spatiile mari care sunt illuminate exista riscul de a aparea monotone daca nu sunt divizate in mai multe suprafete cu nivele de iluminat diferite si pot fi impartite ca o solutie de iluminat in spatii de asteptare, de traffic sau prin spatii in care se doreste impresionarea oameniilor. (exhibition) . Prin acest mod se

imbuntateste orientarea iar prin adaugarea si a altor culori se imbunatatest contrastul iar aceste zone primesc o particularizare.

Lumina indirect ape tavan creaza o lumina directa in camera influetata de reflexia de pe suprafata acestuia.

Cum putem realiza un spatiu care este destinat relaxarii sau sa creeze acest sentiment ? Un iluminat neuniform mai ales a peretiilor. Culorile calde contribuie de asemenea la acest sentiment

Intimitatea – acest sentiment este realizat prin folosirii luminii in umbre. Sablonul petntru aceste spatii este printr-un iluminat scazut si neuniform iar zonele ocupate sa fie inconjurat de o lumina mai mare. Adesea se folosesc lumini vertical in decrimentul luminilor orizontale

Criterile care duc la un design al inuminatului complet: aspectul spatiului si pozitionarea ferestrelor, culoarea si textura suprafetelor, stralucirea (direct glare), Distributia luminii pe suprafete, distributia luminii pe spatial de lucru, modelarea prin lumina a obiectelor, punctele de interes , reflexia suprafetelor, umbrele rezultate, campul visual al ochiului, sisteme de control al iluminatului dar si un factor essential lampile folosite.

Uniformitatea

. We need to pay special attention to controversies that will arise when comparing predictions made under differing models. For example, uniformity recommendations, which are based on visual performance models, advocate near-unity luminance or illuminance ratios.7,8,9 The literature reviewed here, however, suggests that nonuniformity does not degrade visual performance and is acceptable, provided that the task is lit sufficiently. Nonuniformity across a room appears to be preferable to uniformity because it creates interest and can highlightTotusi exista o limita in care neuniformitatea este acceptata si aceea este ‘’dupa ce limita neuniformittea se trensforma in dintr-un contrast atragator intr-o sursa care are o intensitate luminoasa mare’’

5. ConcluziiExperimentele pot comfirma diferite teorii si informatii dar rezultatele acestor studii sunt influentate de preferintele fiecaruia dar pana acum au fost multe incercari de a determina ce conditii rezultate iluminatului oamenii prefer. Oricum se pare ca oamenii prefera iluminatul suprafetelor verticale si iluminatul neuniform poate fi caractericzat ca fiind ‘’interesant’’ dar nu exista un consens in determinarea valorii nivelului de iluminat iar sistemele de iluminat direct/indirect se pare ca sunt mai preferate decat sistemele de iluminat doar direct. Citind experimentele facute de diferiti oamenii pasionati de iluminatul spatiilor imi propun ca urmare a acestui articol realizarea unui spatiu care sa fie iluminat in diferite moduri. Pe un esantion de 100 de oameni spatiul va fi iluminat in cat mai multe moduri (cele prezentate mai sus) in scopul de a afla cat mai multe despre preferintele oameniilor. Un lucru este cert , exista loc de destule informatii in domeniului iluminatului spre o calitate inalta a luminatului dand sentimental de stare de bine oameniilor.

Such research will not take away from the creativity and importance of lighting designers and applications specialists. The research itself will not the answer the question, .How can we provide good lighting quality?. The .how. depends on the lighting systems available (including daylighting), energy-use considerations, and the budget. It requires an integration of lighting and architecture, so that the patterns of

luminances are not only within some acceptable range (set out from research results), but meaningful in the space. The reflectances and finishes of walls, ceilings, floors, window treatments, and furnishings are also part of this answer. These matters lie in the domain ofthe lighting practitioner, whose skills will be increasingly needed to determine how best to achieve the luminous conditions known to contribute to human well-being.