You hang a picture in daylight, and it looks perfect. That evening you switch on the lamps, and the blues have gone grey and the whites have turned cream. The picture hasn't changed. The light has.
A print has no colour of its own in the dark. It shows the colours that the light lets it show. Choosing the right bulb is the cheapest way to make art look better, and most people never think about it.
Colour temperature
White light isn't one colour. It ranges from yellowish to bluish. That range is measured in kelvin, written K, and it is printed on every bulb box.
| Kelvin | Name on the box | What it looks like |
|---|---|---|
| 2200K to 2700K | Extra warm, warm white | Golden, like candlelight or an old filament bulb |
| 3000K | Warm white, soft white | Warm, a little cleaner |
| 3500K to 4000K | Neutral white, cool white | Clean white, neither yellow nor blue |
| 5000K to 6500K | Daylight | Bluish white, like a bright overcast sky |
The names are confusing. A lower number is called warmer, because it looks like firelight. A higher number is called cooler, because it looks like the sky.
What each does to a picture
Warm light, 2700K
- Flatters: reds, oranges, pinks, yellows, golds and browns. They glow.
- Dulls: blues, violets and teals. They move towards grey or green.
- Whites turn cream.
- The mood is soft and cosy.
Neutral light, 3500K to 4000K
- Shows all colours fairly evenly.
- Whites look white.
- The best all-round choice for art, and what most galleries use, at about 3000K to 4000K.
Daylight, 5000K and above
- Flatters: blues, cyans and cool greens. They look crisp.
- Dulls: warm colours, a little. Skin tones and sunsets can look cold.
- The mood is bright and alert, and in a living room in the evening it can feel harsh, like an office.
CRI: the number most people miss
Two bulbs can have the same colour temperature and show colours very differently. The second measure is the colour rendering index, or CRI. It runs up to 100 and tells you how faithfully a light shows colours compared with daylight.
- CRI 80: ordinary household LEDs. Acceptable. Reds in particular look flat.
- CRI 90 and above: colours look full and true. This is what you want on art.
- CRI 95 and above: used in galleries and studios.
A low-CRI bulb leaves parts of the spectrum weak, so the inks that depend on those parts have little to reflect. If your art looks lifeless in the evening, the CRI of the bulb is often the reason. High-CRI bulbs cost a little more and are easy to find. Look for "CRI 90+" on the box.
Matching the light to the art
- Cool art: blues, teals, violets. Neutral white, 3500K to 4000K. Under warm bulbs these lose their clarity. Examples: Blue Mountain Fog, Cosmic Deer, Wolf Pack, Cyber Wave Escape.
- Warm art: reds, pinks, oranges. Warm white, 2700K to 3000K, makes them rich. Examples: Japanese City Punk FX.3, in red and pink.
- Art with both. Much neon art sets pink against blue, or orange against blue. Use neutral white, with a high CRI, so that neither side loses. Examples: Koi Attack, Light Nebula, Hand of the Stars.
- Black and white, silver and grey. Neutral white keeps it crisp. Warm light turns it sepia, which you may or may not like. Examples: Black Hole, Chrome and Blue.
- Pale, snowy pictures. Neutral or slightly cool, to keep the whites clean.
See warm vs cool colours in wall art.
But the room has to be lived in
Most people want warm light in the evening, and they are right. It is restful, and cool light late at night can make it harder to wind down. You don't have to light the whole room for the sake of a picture.
The answer is to give the art its own light.
- Keep the room lamps warm, 2700K.
- Put a small spotlight, track light or picture light on the art, at 3000K to 3500K with a CRI of 90 or more.
The room stays cosy, and the picture is seen properly. The difference between 2700K and 3000K or 3500K is small enough that the two don't clash.
If you want one kind of bulb throughout, 3000K with a high CRI is the best compromise. It is warm enough for a living room and clean enough for most art.
Dimmable and tunable bulbs
- Dimmers let you lower the light without changing bulbs. Some LEDs, sold as "warm dim", turn more golden as they dim, as old bulbs did.
- Tunable white bulbs can be set anywhere from warm to cool with an app or a remote. They let you try each setting on your own art and see which is best. Check the CRI before buying. Some smart bulbs have a low one.
Coloured light
RGB strips and coloured bulbs are a separate matter. They remove colours from a picture, and need handling with care. See RGB lighting and neon art and how to light wall art with LED strips.
Where to put the light
- From above, at about 30 degrees from the wall. This lights the picture evenly and sends reflections down to the floor, away from your eyes.
- Not straight on. A light pointing square at a framed print shows as a bright spot in the cover.
- Not too close. A light near the top of a picture makes a bright top and a dark bottom.
- Use LED. It gives off very little heat and almost no ultraviolet, so it is the safest light for prints. See sun fading.
Matte surfaces are forgiving. Canvas and matte paper don't throw back a glare, which makes them easy to light. See matte vs glossy prints.
Daylight changes too
Daylight isn't constant. It is cool and blue at midday and on overcast days, and warm and golden in the early morning and the evening. A north-facing room has cool, even light all day. A west-facing room turns golden in the late afternoon. A picture will look different at breakfast and at dusk. That is part of the pleasure of having it.
Before you buy
Think about when you will see the piece most. If it is for a room you use mainly in the evening under warm lamps, remember that cool colours will be softer there than on your screen. See why colours look different on screen and in print.
A two-minute test
Take a lamp with a warm bulb and one with a neutral or daylight bulb. Hold each near the picture in turn, with the other lights off. You will see at once which the picture prefers.
The short version
- Kelvin tells you how warm or cool the light is. CRI tells you how true the colours will be.
- Warm light flatters reds and pinks. Neutral light is fairest to everything. Cool light flatters blues.
- For art, choose CRI 90 or more.
- Keep the room warm and give the art a neutral light of its own.
Browse the canvas art collection.