brightness contrast and visual acuity in daytime museum

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Brightness Contrast and Visual Acuity in Daytime Museum Lighting

Dewi Anisa Auriani Pribadi, Joice Sandrasari

Architecture Department, Faculty of Engineering, University of Indonesia, Depok, 16424, Indonesia

E-mail: [email protected]

Abstract

This research is based on a pursuit of theoretical explanation regarding inappropriate lighting condition in daytime museums located in Jakarta. The thesis focuses on brightness contrast between task and ambient lighting systems as the issue that has lessened the quality of vision inside such museums. The issue is further discussed by considering conservation guidelines, general perceived brightness, illuminance ratio, adaptation and glare. A relationship to visual acuity is also included to understand the contribution of brightness contrast in creating a relevant luminous museum environment. Analysis is based on comparison between museum lighting principles and data collected through observation and interviews in three case study museums, and visitor data collected through online questionnaire. The research shows that high task/ambient brightness contrast results in less visual comfort and less visual acuity. Adaptation and glare also contribute in determining visual acuity. The research also shows that none of all case study museums have successfully achieved relevant luminous museum environment. Keywords: museum lighting, brightness contrast, visual acuity, adaptation, glare

Kontras Tingkat Terang dan Ketajaman Visual pada Pencahayaan Museum

Abstrak Skripsi ini bertujuan untuk mencari penjelasan teoretis dari keadaan pencahayaan pada museum di Jakarta yang beroperasi pada siang hari. Penelitian ini berpusat pada kontras tingkat terang antara system pencahayaan Task dan Ambient yang mengurangi kualitas penglihatan di dalam museum tersebut. Pembahasan isu skripsi ini juga didukung dengan pedoman konservasi, tingkat terang umum, rasio illuminance, adaptasi, dan silau. Hubungannya dengan ketajaman visual juga dipertimbangkan untuk memahami kontribusi kontras tingkat terang dalam menciptakan lingkungan museum bercahaya yang relevan. Analisis didasarkan pada perbandingan antara prinsip pencahayaan museum, data observasi dan wawancara di tiga museum studi kasus, dan data pengunjung yang diperoleh melalui kuesioner online. Penelitian ini menunjukkan bahwa kontras tingkat terang yang tinggi pada sistem pencahayaan task/ambient mengurangi kenyamanan dan ketajaman visual. Adaptasi dan silau juga mempengaruhi ketajaman visual. Penelitian ini juga menunjukkan bahwa semua museum studi kasus belum berhasil menciptakan lingkungan museum bercahaya yang relevan. Introduction Conveying visual information regarding the exhibits is the main objective of a museum.

Comfortable visual experience is a priority in creating an enjoyable journey inside the

exhibition space. Therefore, it is important to provide appropriate lighting for the visitors.

Appropriate lighting means creating a relevant luminous environment in which a visitor’s

Kontras Tingkat..., Dewi Anisa Auriani Pribadi, FT UI, 2014

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need of activity and biological visual information needs are being fulfilled. This requires

considerations not only for visual acuity in observing the exhibits and reading written

explanations. Lighting design for museum environment also requires considerations of

illuminants for the surrounding in order to create an overall comfortable environment.

However, the needs for lighting in a museum must be kept in balance with the requirements

of conservation. This calls for attention to deterioration caused by UV radiation and visible

light spectrum. Therefore, both relevant lighting design and protection for conservation need

to be considered in the discussion of museum lighting design.

Unfortunately, the benefits of lighting design are yet to be fully experienced in museums

located in Jakarta. According to personal observation made during previous visits to these

museums, the interior spaces are rarely accommodated with appropriate lighting. Most of

these museums operate during work hours (between 8.00 a.m. to 5.00 p.m.). However, natural

light is hardly used appropriately as a light source. On the other side, artificial light installed

can hardly provide adequate lighting inside the museums. Dark spaces are commonly found

inside the exhibition space. Observing the exhibits and reading written explanations become a

struggle most of the time. Glare is also commonly found on the surface of glass on the

showcase.

The research objective is to find theoretical explanation of inappropriate lighting condition in

daytime museums found in Jakarta. Relationship between quantitative value of illuminance

ratio and qualitative value of brightness contrast is to be clarified in this research.

Relationship between brightness ratio, adaptation, glare, visual comfort and visual acuity is

expected to be understood by the end of this research.

The extent of this research includes basic understanding of lighting design, museum lighting

design principles and the perception of brightness contrast. Topics regarding human eye

adaptation, glare as distraction, as well as visual acuity are also considered. Visual acuity is

discussed in relation to the comfort level in observing exhibits and in reading written

explanations related to the display.

The case study includes three different museums located in Jakarta. The museums are

Museum Nasional Building A, Museum Nasional Building B and Museum Asmat Taman

Mini Indonesia Indah. The case study museums are chosen due to their similarities of daytime


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operation hours and natural history exhibits. However, the three museums have

distinguishable lighting design character, which makes an interesting discussion. Data

collection of the museums includes current lighting condition, interviews and visitor past

experience inside the museums.

Literature Review Lighting design involves a series of distribution and manipulation of light sources to enhance

intended activity inside a space. However, museum lighting design must equally consider the

need of conservation to ensure safety of exhibits. On the other hand, visual comfort and visual

acuity of visitors must be maintained at all time. Therefore, understanding museum lighting

design must include a study of lighting design in general, museum conservation lighting

principles and basic understanding of visual perception. Specific to this research,

understanding of visual perception will be focusing on the perception of brightness.

Lighting determines how a space is perceived by the human eye. This perception can be

formed by receiving visual signals from both natural and artificial light sources. Natural light

source includes daylight from the sun and the sky. Artificial light source includes adjustable

sets of lamps, luminaires and mounting strategies which can be used to create different

lighting systems (Lechner, 2001).

Both natural and artificial lighting are available for use inside daytime museums. However,

specific to museum environment, visual needs for lighting must be balanced with protection

from deterioration for the exhibits. This applies strongly for fugitive materials which include

organic materials originating from living organisms. Protection from ultraviolet and visible

light must be appropriately assigned to exhibition space. Lessening exposure by reducing

illuminance and/or period of contact with visible light is preferable. Thomson (1978)

described that the standard maximum illuminance level for fugitive materials is 50 lux and the

standard maximum illuminance level for stronger materials is 150 lux. Artificial light is more

preferable in both cases since strong daylight is more dangerous yet less manageable.

Adaptation schemes must also be provided accordingly. The human eye must be given at least

a minute or so to adjust to new brightness level (Thomson, 1978), and complete adaptation

takes about an hour (Lechner, 2001).


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These requirements should also be equipped with lighting quality that can create a relevant

luminous environment. Lam (1977) explained that a relevant luminous environment provides

sufficient lighting for the main activity. The main activity of observing exhibits in museums is

best accommodated with Task Lighting System. However, fulfilling biological information

needs in the background is also as important to achieve relevant luminous museum

environment. Therefore, Task Lighting System is usually equipped with Ambient Lighting

System for the surroundings. This creates a foreground-background lighting systems

relationship known as Task/Ambient Lighting System. Emphasis on exhibits by task lighting

system on the foreground ensures that the eye can freely see what it needs to see without any

distraction.

Distraction can be in a form of uncomfortable darkness or brightness level created by

inappropriate brightness contrast between task and ambient lighting systems. Theoretically,

the perceived level of brightness does not have any linear relationship with the measured

value of illuminance. Brightness is a relative value, meaning that it is perceived based on the

comparison with other visible brightness level. Hence, brightness can be observed in terms of

brightness contrast. Two different brightness contrasts create simultaneous contrast, which

can also affect how brightness in general is perceived. High brightness contrast can result in

distracting glare. Glare in itself can also be an additional distraction due to very high level of

illuminance. The absence of these distractions can greatly enhance visual acuity. Visual acuity

is the sharpness of vision. Visual acuity is very important for the main activity in museums

which includes the ability to see details of exhibits and to clearly read their explanation cards.

Research Method Theory literatures are collected from various sources prior to case study observation. Theory

researched includes basic understanding of lighting design, museum lighting design principles

and the perception of brightness contrast. Topics regarding human eye adaptation, glare as

distraction, as well as visual acuity are also considered. Visual acuity is discussed in relation

to the comfort level in observing exhibits and in reading written explanations related to the

display.

Case study museums located in Jakarta are researched through a series of observation,

documentation and interviews. The case study includes three different museums located in


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Jakarta. The museums are Museum Nasional Building A, Museum Nasional Building B and

Museum Asmat Taman Mini Indonesia Indah. The case study museums are chosen due to

their similarities of daytime operation hours and natural history exhibits. However, the three

museums have distinguishable lighting design character, which makes an interesting

discussion.

Quantitative data related to existing lighting condition of the museums are collected during

survey visits to the museums. Supporting qualitative data is also collected during these visits

from personal observation and experience as well as interviews with museum staffs.

Quantitative data regarding visitor visual experience in the museums is collected through

online questionnaire forms. The summary of questionnaire data used is based on the answers

of 20 respondents per case study museum.

The overall theory gathered is used as basic principles in analysing the case study museums.

The data collected during survey visits to case study museums will be compared to respective

questionnaire results. The analysis on the three museums results in the explanation of current

lighting conditions in daytime museums located in Jakarta.

Results and Discussion The case study museums are chosen based on three characteristics: (1) located in Jakarta, (2)

operates during daytime, and (3) displays natural history exhibits. Similarity in location

makes a more relevant sunlight distribution comparison. Daytime operation time makes sure

that both natural and artificial light sources are taken into account. Natural history exhibits is

chosen for the similarity of material strength, which determines 50/150 maximum illuminance

guideline to use.

The three chosen case study museums are Building A and Building B of Museum Nasional in

Central Jakarta, and Museum Asmat of Taman Mini Indonesia Indah in East Jakarta. The

explanation of each museum will include short history and background and current lighting

condition. Proportion of light sources, adaptation schemes and glare will be included.

The analysis will be focusing on brightness contrast between task lighting as foreground

lighting system and ambient lighting as background lighting system. General perception of


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brightness inside the space will also be considered as qualitative measure. Task/Ambient

illuminance ratio will also be included as a comparison.

Table 1: Summary of Case Study Observation

Values

Case Study 1 Case Study 2 Case Study 3

Indonesian Ethnography

Exhibition of Museum Nasional, Jakarta

Humanity and Science and

Technology and Economy

Exhibition of Museum Nasional,

Jakarta

Museum Asmat Taman Mini

Indonesia Indah, Jakarta

Adaptation before entering Sufficient in time span but not in standard illuminance* *scheme 2

Sufficient in time span and standard illuminance

Insufficient both in time span and standard illuminance

The visitor eye is not ready

The visitor eye is ready


General Proportion of Light Sources Daylight is dominant Artificial Light is dominant

Daylight is dominant

Sumatera-Java Annex Java Bali-Papua

Section1,2 Section 3 Section 4a,4b

Section 1,2,3 Corridor A,B

General Proportion of Task/Ambient Brightness

Ambient is dominant Task is dominant Ambient is dominant

Sumatera-Java Annex Java Bali-Papua

Section 1 Section 2,3 Section 4a,4b

Section 1,2,3 Corridor A,B

General Brightness

Spread Mostly Darker and Standard

Mostly Darker and Standard


General Brightness in relation to Task/Ambient Brightness contrast

There is a linear relationship (The higher brightness contrast, the darker)



General Brightness in relation to Illuminance Ratio

No linear relationship



Illuminance Ratio

Spread Mostly too low or too high

Mostly standard and too low

Mostly too low

Illuminance ratio in relation to Task/Ambient Brightness Contrast

No linear relationship No linear relationship


Illuminance Ratio in relation to General Brightness




Breach of 50 lux Yes, in 3/5 Sections Yes, in 1/5 Sections

Yes, in 2/5 Sections

Glare Direct glare Discomfort Discomfort Discomfort

Indirect Glare on Showcase

Disability and Discomfort

Discomfort Discomfort


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The comparison of the three case study museums is shown in Table 1. The lighting quality of

each museum seems to vary. Case Study 2 can be said to be the best of the three, since it has

the least breach of 50 lux maximum illuminance, preserves the dominance of task lighting and

artificial light source use, provides sufficient adaptation scheme, and manages to avoid

disability glare at the same time. Case Study 3 comes second since breach of 50 lux maximum

illuminance and disability glare is still avoided despite other lighting qualities similar to Case

Study 1.

The data collection has also answered some of the questions of the research. Firstly,

task/ambient illuminance ratio does not directly determine or have any linear relationship with

task/ambient brightness contrast. Hence, there must be other factors that help determine the

perception of brightness inside a space.

The pattern in each case study museum shows that where daylight is dominant, ambient light

appears much brighter to the observer. This is most likely because artificial light in most of all

three museums are specifically located to highlight the exhibits. Therefore, the observer’s

brain automatically categorizes daylight as ambient light. This assumption applies even more

in Case Study 1 and Case Study 3, since Case Study 2 does not readily have a large number of

windows compared to the other two. The strong ambient light hence makes the task artificial

light appears much darker.

This shows that brightness is indeed first and foremost a relative value. The perception of

brightness is largely determined by comparison of coexisting brightness levels inside the

space. The explanation also shows that strong daylight upsets the intended lighting system

priority. Visitors must be able to freely see the exhibits they need and want to see. However,

the strong daylight and therefore the strong ambient lighting it creates overpowered the more

relevant signal of task lighting. In other words, the background becomes a distraction for the

foreground. Case Study 2 shows that artificial light can still provide good quality of ambient

light as substitute for the less controllable daylight.

This is an important issue, since the focus selector is automatically attracted to unusual

qualities, in this case the brighter signal. This means that if the visitors would like to


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consciously see the exhibits in Case Study 1 and Case Study 2, they have to concentrate

harder to ignore the bright ambient background. This is even harder to be done since there is

still adaptation and glare issues that the visitors have to deal with at the same time.

Therefore, in order to provide relevant luminous environment, light sources emitting extreme

brightness anywhere inside the space should be avoided. We must at least make sure that

brightness contrast is preserved constantly throughout the space to eliminate distracting

brightness contrast.

Secondly, the comparison also shows that the higher the brightness contrast between task and

ambient lighting, the darker the museum space is perceived. This is true despite of any

measured illuminance ratio, light source proportion, adaptation scheme and glare level. The

perception of general brightness has also shown the importance of simultaneous contrast.

Adjacent spaces with the same task/ambient brightness ratio is perceived similarly in terms of

general brightness. On the other hand, adjacent spaces with different brightness ratio will

have different general perceived brightness. This shows that visible brightness contrast from

adjacent spaces is added into the comparison in determining general brightness of the space

we inhabit.

Hence, it is important to understand that preservation of brightness contrast throughout the

exhibition space as a whole is very important. Preserved brightness contrast inside one

exhibition section can be upset by another section with different brightness contrast. This will

make the space appear darker or brighter than intended. When the space appears darker as a

result, biological comfort of visitors may be affected negatively. This will reduce the

relevance of the luminous environment.

In order to understand further about the effect of brightness contrast to visual experience of

visitors, a study of visual comfort and visual acuity will be discussed in the next chapter. The

relationship between brightness contrast, adaptation and glare will also be discussed further in

the next chapter.

Online questionnaire response from selected 20 respondents for each museum is used to

collect visitor data to support the analysis. The data will also be used to reassess data gathered

in the previous chapter. Questions regarding proportion of light sources proportion, adaptation


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inside exhibition space, general perception of bright and dark areas, indirect glare on

showcase glass surface and inclination to revisit are also included as supporting data.

Table 2 shows that in general, artificial light gains more favour from the respondents. This

shows that daylight is indeed perceived as distraction due to its strong intensity. It seems that

respondents also associates daylight as ambient light, and therefore bothered when it takes

over the intensity of artificial light. It seems that the strong daylight in Case Study 1 makes

the artificial light appear less helpful, evident from the general perception of light sources

being distractive.

Table 2: Summary of Comparison between Case Study Observation and Questionnaire Respondent Answers

Values

Case Study 1 Case Study 2 Case Study 3

Indonesian Ethnography Exhibition of

Museum Nasional, Jakarta

Humanity and Science and

Technology and Economy Exhibition of Museum Nasional,

Jakarta

Museum Asmat Taman Mini

Indonesia Indah, Jakarta

Adaptation Prior to entrance to exhibition space

Sufficient in time span but not in standard illuminance* *scheme 2

Sufficient in time span and standard illuminance

Insufficient both in time span and standard illuminance


The visitor eye is ready


First Impression Dark Bright Bright**

Overall Impression

Dark* *one respondent changed to bright after visiting for more than an hour

Bright Bright** **two respondents mentioned dark upon entering and leaving, after visiting for less than 30 minutes

Light Sources General Proportion of Light Sources

Daylight is dominant Artificial Light is dominant

Daylight is dominant

Influence of light sources in General

Distracting Helpful Helpful

Artificial Light is more favoured



Task/Ambient brightness

General Proportion of Task/Ambient Brightness

Ambient is dominant Task is dominant Ambient is dominant

General perceived brightness

Spread Mostly Darker and Standard



General perceived brightness as mentioned by

More dark than bright areas

More dark areas than bright areas

More bright areas than dark


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Case Study 1 and Case Study 2 shows that the better the adaptation scheme, the brighter the

space is perceived despite of the low illuminance level. However, Case Study 2 shows that

despite lack of adaptation, the space can still be perceived as bright. This is probably due to

the strong daylight distributed to the interior from open double-doors. Respondents have also

maintained their first impression of brightness until the end of their visit. However, one

respondent spending more than an hour inside Case Study 1 changed their impression to

bright. This shows that after the eye is given enough time to adjust inside exhibition space, the

perception of general brightness can still be altered.

The general brightness inside the space is perceived differently in each case study.

Respondents see more dark areas than bright areas in Case Study 2. One might argue that it is

due to the absence of extreme daylight distribution. However, respondents see more bright

areas than dark areas only in Case Study 3, although Case Study 1 also has strong daylight

distribution. Therefore, strong daylight might not be the only determinant. Most likely, the

other factor is the distributional pattern of daylight itself. Even though daylight is not

distributed evenly inside each section in Case Study 3, it is distributed in a consisted pattern

throughout the whole museum. Therefore, the consistent pattern set the general brightness

inside the museum by maintaining the same simultaneous contrast combination.

Case Study 1 suffers from the danger of disability glare on showcase glass covers. This is a

great concern, since disability glare means that visitors are unable to receive important visual

signal from the exhibits, let alone to observe detail and properly read explanation texts. Most

respondents Glare Direct glare Discomfort Discomfort Discomfort

Indirect Glare on Showcase





Visual Comfort

General Viewing

Fairly Comfortable Comfortable Fairly Comfortable

Visual Acuity Observing Details

Fairly Comfortable Comfortable Fairly Comfortable

Reading Texts Fairly Comfortable Comfortable Comfortable

Revisit 10 Decline 2 mention darkness as reason

4 Decline No mention of lighting as reason

10 Decline 1 mentions natural light is too overwhelming as reason


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respondents evidently agree that this is the case since they can hardly reach a comfortable

experience in seeing, observing details and reading texts.

In comparison, discomfort glare results in different answers of respondents regarding visual

comfort and visual acuity in Case Study 2 and Case Study 3. It shows that discomfort glare

can still be influenced by other factors to improve the visual experience inside the exhibition

space. Respondents are generally comfortable in Case Study 2 since they are given

appropriate adaptation scheme and good proportion of task lighting as the foreground of

lighting systems inside the space.

These two factors maintain visual comfort and visual acuity despite the dominance of dark

areas over bright areas and the existence of discomfort glare on showcase glass surface.

Therefore, discomfort glare has less severe effect on visual comfort and visual acuity

compared to disability glare. However, this is not to say that discomfort glare is not to be

removed wherever possible.

In conclusion, the respondent answers compared to case study observation shows that general

brightness inside a space is firstly determined by the brightness contrast inside a space. In

terms of task/ambient brightness contrast and light sources proportion, there is a general

favour for artificial lighting, which is generally expected to function as task lighting.

Therefore, task lighting must always be preserved as the foreground lighting system and

extremely bright light sources should be avoided at all cost.

General brightness can also be determined before visitors enter the exhibition space through

adaptation method to set new general brightness standard. However, adaptation can also alter

the perception of general brightness after the eye adjusts for more than an hour inside the

exhibition space.

Indirect glare on showcase glass cover can be avoided by maintaining the right brightness

contrast as mentioned above. This might include other strategies such as using the right

shading on daylight sources and using the right angle for lighting fixtures. However, disability

glare must be avoided at all cost, since it greatly reduces relevance in the luminous museum

environment in terms of visual comfort and visual acuity. On the other hand, discomfort glare


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can still be assisted with good brightness contrast and appropriate adaptation scheme.

Nevertheless, discomfort glare is not to be maintained wherever improvements can be made.

In general, the general lighting condition comparison of the three case studies has not been

changed, but rather confirmed by the respondents. Case Study 1 still struggles the most with

brightness contrast issues which lead to hardly comfortable visual experience in general. This

is also evident from the fact that 2 out of 10 respondents who declined to pay another visit

mention lighting condition as their reasons. Case Study 3 is positioned in the middle in the

comparison, with a mix of lighting issues and achievements, and only 1 out of 10 respondents

who decline another visit mentioning lighting as his/her reason.

Case Study 2 has the best condition compared to the other three with dark areas dominance

and discomfort glare as the only brightness issue. It has only 4 people declining to revisit with

no complain of lighting condition as the reason. However, neither of three case study

museums have achieved outstanding brightness ratio condition due to existence of dark spaces

and glare in general, and the lack of very comfortable visual experience inside the exhibition

space.

Unfortunately, according to the analysis above, out of the three case study museums, none

have provided relevant luminous museum environment. The maximum 50 lux illuminance for

fugitive materials is still breached in all three museums. One museum out of three also did not

use any UV protection at all.

Each section seems to have preserved their respective Task/Ambient brightness contrast.

However, the contrast is still too high, usually due to extreme sunlight side windows or open

double doors. This results in high brightness contrast, which also create direct and indirect

glare. This makes the section appears darker. Although in one out of three museums the

extreme of daylight is strongly reduced, all case study museums suffer from simultaneous

contrast created by adjacent space. The condition is worsened by the lack of proper adaptation

scheme prior to entrance in two out of three museums.

As a result, high brightness contrast creates unhealthy balance between task lighting on

exhibits (foreground) and ambient lighting on the surrounding (background). Strong daylight

is not only dangerous in terms of material deterioration, but it can also deny the freedom of


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seeing what we want and need to see. Its high intensity will result in distraction of direct

glare. The high brightness contrast resulting in a darker space might also make us feel

biologically threatened subconsciously. This will divide our focus of attention that is ideally

preserved for the exhibits.

General comfort in seeing is basically lessened or gone by this stage, let alone any

concentration for observing details and reading texts. Besides being continuously bothered by

aforementioned visual noise, there is still indirect glare on glass surfaces. In the end, it is

almost a wonder that any level of visual acuity can be achieved at all in such condition.

Conclusion

Lighting in museum environment must be designed with conservation strategies in mind.

Ultraviolet and visible light is after all the most dangerous deterioration agent for exhibits.

This principle is especially important in museum displaying exhibits with fugitive materials.

Although sacrifices in lighting can possibly reduce the viewing comfort of these exhibits,

losing exhibits to deterioration can result in the museum having nothing to display at all.

In order to create relevant luminous museum environment, the visitors should be free to see

what they want and need to see regarding the exhibits. Specifically, observing exhibit details

and reading explanation texts. This can be achieved by ensuring a good balance between

foreground and background. The focus selector must not be distracted by the background, so

concentration of viewer can freely move on the foreground.

This foreground-background balance applies to different lighting systems used inside

exhibition space, namely Task/Ambient Lighting System. The quality of lighting can be seen

from how bright and dark it is perceived, and whether it enhances the intended activity. The

quality of brightness is first and foremost a relative value. Therefore, its qualitative

measurement is usually referred to as brightness contrast. Brightness contrast is not directly

determined by illuminance ratio. However, brightness contrast is perceived based on the

extremes of light sources inside the space. These extremes, such as strong daylight can also

lead to the phenomenon of direct and indirect glare.


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Brightness contrast also determines the general brightness perceived inside a space. The

higher the contrast, the darker the space in general is perceived. However, simultaneous

contrast also contributes to the equation. Differences of brightness contrast level between two

adjacent spaces can make the one with higher contrast appear even darker and the one with

lower contrast appear brighter. Nevertheless, adaptation of the eye may also alter the general

brightness perceived inside the space.

In conclusion, proper task/ambient brightness ratio has not been maintained properly in all

natural history daytime museums in Jakarta observed in this research. This unfortunately

results in irrelevant luminous environment. It is not to say that they represent the general

lighting condition of museums in Jakarta or in Indonesia in general. The issue of brightness

also should not be taken as the only consideration in creating relevant luminous museum

environment. Hopefully, the humble solution offered in this research can be any of use in

improving museums in Jakarta and maybe in other parts of Indonesia.

Suggestions There are several steps that can be performed to provide relevant luminous museum

environment through task/ambient brightness contrast management. These steps are gathered

as a result of theoretical understanding gained from analysis done in this research.

The steps include:

1. Find maximum illuminance guideline and proportion of light source according to

the material.

2. Use protection from Ultraviolet wherever necessary, especially for daylight

distribution.

3. Decide on task and ambient brightness contrast inside the space according to

qualitative assessment, while maintaining maximum illuminance level.

4. Maintain task/ambient brightness contrast by

a. Avoiding extremes (light sources with brightness level that is too high or

too low which can upset intended brightness ratio),

b. Spreading both task and ambient lighting consistently throughout one

section of exhibition space,


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c. Avoiding glare at all cost by shading strategies, material choice or simply

using appropriate angle for lighting fixtures,

d. Maintaining the same task/ambient brightness ratio and even spreading for

all exhibition space to create the same brightness level perceived in each

section of the space, and

e. Providing adaptation scheme through entrance space with the same general

brightness. The process should at the same time put visitors at least one

minute apart between the outdoor and the exhibition space.

This research and the resulting suggestion above are still far from complete. Therefore future

research regarding the topic is highly encouraged. There are several suggestions of topics for

future research. First, further defininition and analysis on extreme brightness qualities and its

effects on task/ambient brightness ratio. Second, definition and strategies to develop what is

considered as good task/ambient brightness ratio. Third, factors other than extremes,

simultaneous contrast, adaptation and glare which influence task/ambient brightness ratio.

Last but not least, research using the same objective and method as this thesis with more

thorough data collection and analysis will absolutely be most welcome.

References

Bapak Asep, 17 May 2014. Interview on UV Protection and Lighting Fixtures in Museum

Nasional. Jakarta.

LAM, W. M. C. (1977). Perception and Lighting as Formgivers for Architecture. New York:

McGraw-Hill.

LECHNER, N. (2001). Heating, Cooling, Lighting: Metode Desain untuk Arsitektur. Jakarta:

PT. RajaGrafindo persada.

THOMSON, G. (1978). The Museum Environment. Butterworth.


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