You have to worry about the type of lightbulbs and the UV, and the infrared radiation, and now you also have to keep in mind the museum light color temperature. But what does that mean and why is it relevant?
Imagine you are about to go into a cafe or restaurant for what you hope will be a romantic date and you have a choice between two places. One of them has a white light setup and the other a golden light. You will probably go for the golden place. What if, on the other hand, you are meeting an online seller to buy a coat you saw online? In that case, you’d do better to examine your purchase in the white light.
Here’s another example. Some of us like to work in cold white light while some of us prefer warm orange lights. Why? Here are some reasons you might hear:
- Orange light makes me sleepy. It makes me want to rest, not work.
- Bluish light makes me feel energized!
- I hate cold lights for working. It makes me feel sanitized and bored. White light makes my eyes tired.
- I can’t see what I’m doing properly in warm lights. Everything looks orange.
The “temperature” of a light source when we are referring to its coloration, not its actual infrared radiation, will affect not only how other objects look to us, but also how we feel. So how do you pick the correct museum lighting color temperature for your collections and your patrons? Will it affect the energy efficiency of your lighting system? And does it affect degradation rates? Let’s learn a bit more below.
Understanding Color Temperature
The Correlated Color Temperature (CCT), also just called color temperature, is measured in degrees Kelvin and determines the hue or visual “warmth” or “coolness” of a light. It can be a bit confusing because you would expect the lower temperatures to be considered colder, but it actually works the other way around.
As you can see in this illustration, “warm” redder light is to the left with the lower K temperatures and grows “colder” or bluer as it moves to the higher numbers.
A candle will have a color temperature of about 1800 K at the very left end of this spectrum.
For halogen and incandescent light bulbs, the color temperature will be directly related to the temperature of the filament inside the bulb. According to the Canadian Conservation Institute Technical Bulletin 36 on LED lighting, you will find traditional incandescent lights at around 2800 K and quartz halogen lamps around 3000 K. In other words, they will give out “warm” light.
If you have decided to use natural lighting as part of your museum lighting strategy, be aware that daylight can vary from 3000-10,000 K depending on cloud cover and the time of day. That means that you can have a very cold light in the morning and a very warm light at dusk. Make sure you talk to a lighting professional to take into account the natural changes of daylight and the curatorial requirements of your exhibition.
How does museum lighting color temperature affect experience?
The color temperature of light affects how we perceive colors, as different light sources can enhance or diminish certain hues. For example, warm light can make reds and yellows more vivid, while cold light can make blues and greens more vibrant.
The color temperature of light also affects the mood and atmosphere of the exhibition space, as warm light can create a cozy and intimate feeling, while cold light can create a bright and spacious feeling.
Unfortunately, or perhaps fortunately? studies on color temperature in museum or gallery settings do not agree on what the “best” color temperature is for visitor experience. A 2015 study found participants were most “comfortable” viewing paintings in a space with a warm 2850 K light but found paintings best “definition” at 6500 K – which incidentally is about the color of daylight. Other studies from around 2014 to 2017 also seem to suggest participants prefer temperatures close to the daylight-like 5000-6000 K range. Generally speaking, then, we can say there is no “best” theoretical lighting color temperature for an exhibition.
How do you choose your lighting color temperature?
Take into account the following considerations:
- The type and style of your institution: Are you a modern art or contemporary art museum with large open spaces and white or concrete walls, or are you a historical society in a historical property from the 18th century with small rooms that would have been traditionally candlelit?
- The type and style of the artworks: Different artworks may require different color temperatures to highlight their features and convey their message. For example, paintings with warm colors may look better under warm light, while sculptures with cool colors may look better under cold light. Portraits with a lot of skin tones will benefit most from warmer lights. Artwork with fluorescent paint will do better with colder lights.
- The theme and purpose of the exhibition: Different exhibitions may have different goals and intentions, which can influence the choice of color temperature. For example, an exhibition that aims to evoke a historical or nostalgic mood may benefit from warm light, while an exhibition that aims to showcase industrial or innovative works may benefit most from cold light.
- The original intent of the artist: It is possible that a living artist will want their artwork displayed in a particular way, under a particular light. It is also expected that if you are exhibiting historical objects, that they would be more accurately represented by candlelight tones.
- The preference and expectation of the visitors: Different visitors may have different preferences and expectations for museum lighting, which can affect their satisfaction and enjoyment. For example, some visitors may prefer warm light for its natural and comfortable feeling, while others may prefer cold light for its clear and accurate vision. Remember that we are not all the same and people with disabilities might enjoy their visit under particular light temperatures and intensities.
Will certain color temperatures affect deterioration rates?
When it comes to fading and light damage, you should be more concerned about the quality of your lightbulb, the amount of visible light, UV and infrared radiation your objects get, and the amount of time your objects are exposed. A warm lightbulb that has been chosen for its excellent Color Rendering Properties and low UV emissions, or which has a good UV filter on it, will not cause any more comparable damage than a cold lightbulb of the same characteristics. When you worry, worry about quality, not color.
Caveats when picking museum lighting color temperature
While it is possible to say that color temperature will be mostly about preference, this does not necessarily mean you can have two exhibition spaces next to each other with completely different color temperature light bulbs in them. Remember that your visitors’ eyes will take a few minutes to adjust to changes in lighting from one space to another. While you can use a range of color temperatures to create contrast and variety, if you change lighting colors (or even brightness) suddenly, you can negatively affect visitor experience. Speak to your exhibitions officers and lighting specialists to find a combination that works well for you.
Color temperature in light bulbs can be directly related to the type of light bulb itself. For example, while you should be able to buy LEDs in just about any color you are looking for, this is not the case for incandescent or halogen bulbs, where you will be limited to the warmer hues.
Don’t forget color temperature is just another aspect of lighting systems, and not necessarily the most important one. Regardless of the temperature you buy, make sure your Color Rendering Index (CRI) is high enough (at least 85-90) – the quality of the light should be good regardless of its hue.
So much information! Please just tell me what to do
If this is all just too much for you, here are some baseline recommendations for museum lighting color temperature:
- Beware non LED lamps with 2500-2900 K. They could have very bad color rendering properties.
- If you want warm LEDs to replace your old filament bulbs, 2700-2800 K is a good parkball number.
- Beware pre-2018 and/or bad quality LEDs. They will be just as harmful, if not worse, than traditional halogen or incandescent light bulbs.
- 3000 K is a good all-purpose color temperature choice if you’re not worried about minor details.
- For lab spaces or conservation areas, talk to your staff. They will probably prefer lights closer to daylight temperature.
- Regardless of temperature, check for UV and IR emissions from your lamps.
- Regardless of temperature, don’t forget light damage is related to exposure time, so be aware of your light quotas.
- Regardless of temperature, choose high quality lights with high Color Rendering Indexes.
Conclusions
The choice between warm or cold museum lighting color temperature depends on various factors, including the specific needs of the collection and the desired visitor experience. In a field so driven by standards and guidelines, it can be comforting to know that there is no “best” color temperature for lighting, so you do enjoy flexibility in this respect. However, don’t forget that light damage is directly related to exposure time and intensity as well as UV and IR, so when you are thinking about temperatures, don’t forget to prioritize quality and continued monitoring.
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