Color temperature is a number, measured in kelvin (K), that describes how orange or how blue a light is. Candlelight is about 1,800K and deep orange, midday sun about 5,500K and close to white, and the blue sky that lights a shadow 10,000K or more. It matters because your camera records the color of the light on everything it touches, while your eyes quietly ignore it.
The sunrise above shows two lights at once. The sun on the horizon is low and orange, and it turns the trees on the island a warm red. The snow in the foreground is lit mostly by the sky, which is blue, so the same white snow comes out cool. Nothing in the scene changed color. The light did. Once you can read that, you can predict what a photo will look like before you take it, fix it when it goes wrong, and use it when it helps.
Why low numbers are warm: the glowing-metal scale
Heat a piece of iron and it starts to glow. First dull red, then orange, then yellow-white, and if you could keep going without it melting, bluish white. Physicists describe an ideal glowing object, a “black body”, whose color depends only on its temperature. Color temperature borrows that scale: a light has a color temperature of 3,000K if it matches the color of a black body heated to 3,000 kelvin. The kelvin is the scientific unit of absolute temperature, named after the physicist William Thomson, Lord Kelvin. Its zero is absolute zero, and each kelvin is the same size as one degree Celsius, so a “kelvin value” is simply a temperature counted up from there.
That is why the scale runs the opposite way to the words artists use. In paintings, orange and red are “warm” and blue is “cool”. On the kelvin scale, orange light comes from a cooler glowing object and blue light from a hotter one. So low numbers mean warm-looking light and high numbers mean cool-looking light. Two small points of language: kelvin takes no degree sign (write 5,500K, not 5,500°K), and the number says nothing about how hot the lamp or the room is. A 6,500K LED panel runs no hotter than a 2,700K one.
Only light that comes from heat truly has a color temperature: flames, the sun, and incandescent and halogen bulbs. Everything else, including LEDs, fluorescent tubes and streetlights, gets a “correlated color temperature”, the nearest match on the scale. That difference matters later on this page, because a correlated number can hide a green or magenta lean that the kelvin value does not describe.
The color temperature of common light
These are typical values. Real sources vary with the bulb, the weather, the haze in the air and the height of the sun, so treat each as a range, not a fixed fact.
| Light source | Typical color temperature | How it looks to a camera set for daylight |
|---|---|---|
| Candle flame, campfire | about 1,800 to 2,000K | Deep orange |
| Sodium streetlight | about 2,000K (correlated, very narrow spectrum) | Orange-yellow, hard to correct |
| Sun right at the horizon | about 2,000 to 3,000K | Orange to red-orange |
| Household incandescent bulb, “warm white” LED | about 2,700 to 3,000K | Orange-yellow |
| Halogen and studio tungsten lamps | about 3,200K | Yellow-orange |
| Low sun in the golden hour | about 3,000 to 4,000K | Golden |
| “Cool white” fluorescent and LED | about 4,000 to 5,000K (correlated) | Near neutral, often a little green |
| Direct sun in the middle of the day | about 5,000 to 5,500K | Neutral |
| Electronic flash | about 5,500 to 6,000K | Neutral to faintly cool |
| Overcast sky | about 6,000 to 7,500K | Slightly blue |
| Open shade on a clear day | about 7,000 to 10,000K | Clearly blue |
| Clear blue sky, with no direct sun | 10,000K to well over 15,000K | Strongly blue |
Notice how much of the table is daylight. “Daylight” is not one color. The sun at the horizon and the shade on a clear afternoon are thousands of kelvin apart, and that is the single most useful thing on this page for anyone who shoots outdoors.
Daylight is not one color: sun, sky and the time of day
Air scatters short, blue wavelengths much more than long, red ones. For blue light at 450 nanometers against red at 700, the ratio is (700 ÷ 450) to the fourth power, which is about 5.9, so blue is scattered nearly six times as strongly. That one fact explains most of outdoor color:
- The sky is blue because it is made of scattered sunlight, and most of what is scattered is blue.
- The low sun is orange because its beam crosses far more air. Near the horizon the sunlight passes through roughly 38 times as much atmosphere as when the sun is straight overhead, and most of the blue has been scattered out of the beam by the time it reaches you.
- Shadows on a clear day are blue because the sun cannot reach them. They are lit by the sky, and the sky is a very high color temperature light.
- Overcast light is slightly cool and even, because clouds mix the sun and the sky into one soft source, a little bluer than direct midday sun.
- After sunset everything is lit by sky, with no direct sun at all, which is why blue hour is blue.
The frosty island above is the clearest proof that the sun and the sky are two different lights. The snow is the same white everywhere. Where the sun reaches it, it records close to neutral. Where the trees cast shadows, the snow is lit only by the sky and comes out blue. No white balance setting can make both areas white at once, because they are lit by light thousands of kelvin apart.
The sky itself is not one color either. At sunrise, the part near the sun is orange and the part overhead is still blue, as in the bridge photo. As the sun climbs, the direct light cools quickly: deep orange at the horizon, golden for the first hour or so, and close to neutral by mid morning. In the evening the same sequence runs in reverse. The height of the sun matters far more than the clock, so the timing shifts with season and latitude.
Want to know when the low, warm light starts and ends where you are? The golden hour calculator works it out for any date and place, and golden hour photography covers how to use it.
This is also why open shade is flattering but blue, and why a portrait in shade often needs warming. The light is soft because it comes from the whole sky, and it is blue for exactly the same reason.
Why your eyes miss it and the camera does not
Your visual system adjusts to the color of the light around you. Walk from a sunny street into a lamp-lit room and the room looks orange for a moment, then within a minute or so the walls look white again. This is called chromatic adaptation, and it is why color temperature surprises people: you did not see the orange, so the orange photo looks like a camera fault.
A sensor has no such habit. It counts red, green and blue light and records what arrived. Under a household bulb far more red arrives than blue, so a white wall records as orange. In shade far more blue arrives than red, so a white shirt records as blue. The camera is not wrong. It is reporting the light more honestly than your eyes do.
Adaptation is one of several ways your eyes differ from a sensor; how the human eye compares to a camera covers the others, including dynamic range.
Two kelvin numbers: the light’s and the camera’s
Most confusion about color temperature comes from using one word for two different numbers.
- The light’s color temperature is a property of the scene. A lamp is about 2,700K. Shade is about 7,500K.
- The camera’s white balance setting, also given in kelvin, is what you tell the camera the light is, so it can remove that color.
When the two numbers match, white objects come out white. When the setting is lower than the light, the photo goes blue. When the setting is higher than the light, the photo goes orange. That is why moving the camera’s kelvin slider up makes the photo look warmer: you are telling the camera the light is bluer than it is, so it adds orange to cancel blue that is not there.
| Light in the scene | Camera set to 3,200K | Camera set to 5,500K | Camera set to 7,500K |
|---|---|---|---|
| Lamp, about 2,700 to 3,000K | Near neutral, a touch warm | Orange | Strongly orange |
| Midday sun, about 5,500K | Strongly blue | Neutral | Warm |
| Open shade, about 7,500K | Very blue | Blue | Neutral |
Read across a row and you see one light rendered three ways. Read down a column and you see one camera setting meet three lights. Neutral sits where the numbers match.
Want to feel this rather than read it? The white balance page has a tool where you pick a light and drag kelvin and tint until the whites turn white, and it covers presets, Auto and custom settings in full.
Try it with the white balance tool below: move the kelvin slider and watch which way the picture shifts, then find the setting that makes the scene look neutral.
Why the kelvin slider feels uneven: mireds
Kelvin steps are not equal steps of color. A 500K change at the warm end is a large, obvious shift. The same 500K change at the cool end is barely visible. A second unit, the mired (short for “micro reciprocal degree”), fixes this. It is one million divided by the kelvin value, and equal mired steps look roughly equal to the eye.
| Kelvin step (500K each) | Mireds at each end | Mired change |
|---|---|---|
| 2,500 to 3,000K | 400.0 to 333.3 | 66.7 |
| 3,000 to 3,500K | 333.3 to 285.7 | 47.6 |
| 5,500 to 6,000K | 181.8 to 166.7 | 15.2 |
| 6,000 to 6,500K | 166.7 to 153.8 | 12.8 |
| 9,500 to 10,000K | 105.3 to 100.0 | 5.3 |
The step from 3,000 to 3,500K is about 3.7 times as large as the step from 6,000 to 6,500K, even though both are “500K”. Turn it around and the same visible shift of 50 mireds is about 530K starting from 3,000K (to roughly 3,530K), about 2,090K starting from 5,500K (to roughly 7,590K), and about 3,130K starting from 6,500K (to roughly 9,630K). In practice: fine tune in small kelvin steps under lamps, and in big ones in shade.
Mireds also explain colored filters. A gel shifts light by a fixed number of mireds, and gel shifts add up. Turning 5,500K daylight into 3,200K tungsten color is 312.5 minus 181.8, a shift of about +131 mireds. A gel built to do half of that, +65 mireds, turns a 5,500K flash into about 4,050K. Two of them together make roughly 3,200K. The same +131 mired gel over a 6,500K source gives about 3,500K, a much larger change in kelvin, because the gel works in mireds, not kelvin.
When a kelvin number is not enough: tint and spectrum
The kelvin scale describes one line of colors, from orange to blue. Light can also lean green or magenta, off that line. Many fluorescent tubes and lower quality LEDs cast green, and some LEDs lean magenta. No kelvin value cancels a green cast. That needs the separate tint control, which moves color between green and magenta. Skin shows it first: a slight green tint makes people look ill long before the rest of the frame looks wrong.
Two lights can share the same correlated color temperature and still show colors differently, because the number describes only the overall color, not what the light is made of. Sunlight and incandescent light contain every color in a smooth spread. Many LEDs and tubes have peaks and gaps. A measure called the color rendering index (CRI) scores how faithfully a light shows a range of test colors against a reference, out of 100. A low CRI light can make reds dull or skin flat even when white balance is perfect, and no setting can add back color that was never in the light.
Sodium streetlights are the extreme. The old low-pressure kind puts out almost all its light in one narrow band of yellow-orange, and even the common high-pressure kind leaves most colors weak. White balance can turn the orange toward gray but cannot restore the blues and greens. Accept the color as part of the night, add your own light, or convert to black and white.
Seeing a color you cannot fix with the kelvin slider? Color cast covers where casts come from and how to remove them, including tint.
Mixed color temperatures in one scene
A white balance setting can match only one light. A room lit by a 2,700K lamp and a window full of 7,000K sky has two, and whatever you choose, one part of the frame goes orange or blue. Dusk in a city does the same, with warm windows and streetlights against a deep blue sky. There are four ways to handle it:
- Remove one source. Switch off the lamp, draw the curtain, or move your subject so one light dominates.
- Balance for the subject. Set white balance for the light on the face or the main object and let the rest go warm or cool.
- Match the sources. An orange gel on a flash makes it match lamp light, so one setting works for both. Balancing flash and ambient light covers how.
- Correct in editing, area by area. With a RAW file you can warm one part of the frame and cool another. Fixing mixed light in post walks through it.
Often the best answer is none of these. Warm windows against a blue dusk sky is one of the most reliable color pairings in photography, and it exists only because the two lights differ. Splitting the difference with a middle setting usually leaves both looking slightly wrong.
Using color temperature on purpose
Neutral is a choice, not a rule. A sunrise corrected to neutral loses the reason you got up for it, and a candlelit table turned gray stops feeling like candlelight. Warm light reads as comfort, evening and home. Cool light reads as cold, early morning, distance or quiet.
Look back at the two snow photos on this page. In the sunrise at the top, the warm direct light on the trees is what says “dawn”. In the frosty island, the blue in the shadows is most of what says the air was cold. Warm those shadows to pure white and the scene loses its temperature and its time of day, even though nothing else changes.
To keep or strengthen warmth, set the camera’s kelvin value higher than the light, or choose the Cloudy or Shade preset. To make a scene cooler, set a lower value or choose Tungsten. Shooting RAW lets you decide later with no loss of quality, because the white balance is stored as an instruction rather than applied to the pixels. A JPEG has it applied when you press the shutter, and big corrections afterward cost color quality.
Try it in the simulator below: set a white balance at least 1,500K warmer than the light in the scene, and watch the camera lay a golden glow over everything.
Want to use color for mood across a whole photo? Color grading goes further than white balance, and color in photography covers how colors work together.
Test your eye: pick the photo below with the warmer color cast, then read why.
Warm white balance shifts the image toward orange and yellow, the look of tungsten light or sunset. Cool white balance pushes toward blue, the look of shade, overcast skies, or uncorrected indoor light.
Common mistakes with color temperature
- Thinking a higher kelvin number means warmer light. The camera slider makes it feel that way, but the light at 8,000K is blue. The slider is the correction, and it runs opposite to the light.
- Treating daylight as one color. Midday sun, shade, overcast and dusk can differ by several thousand kelvin. A Daylight preset keeps them honest, it does not make them the same.
- Trusting your eyes on the color of the light. Your vision has already adapted. Trust a white card, a gray card or the camera’s preview instead.
- Letting Auto neutralize the light you came for. Auto white balance tries to remove color casts, and a sunset is one big color cast. Use Daylight or a fixed kelvin value when the color is the subject.
- Expecting kelvin to fix every lamp. Green and magenta need tint, and narrow-spectrum light like sodium cannot be fully corrected at all.
- Splitting the difference in mixed light. A middle setting usually makes both lights look slightly off. Pick one, or keep the contrast on purpose.
- Thinking color temperature is heat. It describes color only. A cool-looking 6,500K bulb is no hotter than a warm 2,700K one.
Try this: one white card, four lights, ten minutes
You need a sheet of white paper or a gray card, and a camera or phone that lets you fix the white balance. Set it to the Daylight preset, or 5,500K, and leave it there for every shot. On a phone, use a mode that lets you set or lock white balance.
- Photograph the card in direct sun, filling most of the frame.
- Photograph it in open shade on the same side of the building.
- Photograph it indoors close to an ordinary lamp, with the curtains drawn if you can.
- Photograph it under any fluorescent tube or LED ceiling light you have.
How to judge it: put the four frames side by side. The card is the same in each, so any color you see is the color of the light. The sun frame should look close to white, the shade frame blue, the lamp frame orange, and the tube or LED frame may lean green or magenta as well as warm or cool. If you shot RAW, click each card with your editor’s white balance eyedropper and note the kelvin value it chooses. Expect something near 2,700 to 3,200K for the lamp and 7,000K or more for clear-sky shade, though your lights may differ. Then notice that to your eye, the card looked white every time. That gap is what this whole page is about. Printer paper sometimes contains brighteners that glow faintly blue in daylight, so a gray card gives cleaner readings.
Want to check you can predict which way a light will shift a photo, and how to correct it? Try the white balance and color temperature quiz.
Color temperature questions
Is 5,500K the same as daylight?
It is a convention. Around 5,500K is close to direct sun in the middle of the day, so it is what camera Daylight presets and flashes are built around. Real daylight runs from about 2,000K at sunrise to well over 10,000K in shade, so “daylight” on a camera means midday sun, not all outdoor light.
What color temperature is golden hour?
Roughly 3,000 to 4,000K while the sun is low, and lower still, around 2,000 to 3,000K, as it touches the horizon. Haze, smoke and dust lower it further. Shadows during golden hour are still lit by blue sky, which is why golden hour photos often mix warm highlights with cool shadows.
Why do my indoor photos look orange?
Household bulbs, including “warm white” LEDs, are around 2,700 to 3,000K, far warmer than the daylight a camera is often set for. Your eyes adapted so the room looked normal, but the camera recorded the orange. Set white balance to Tungsten or about 3,000K, or correct it afterward if you shot RAW.
What do the kelvin numbers on light bulb boxes mean?
They are the bulb’s correlated color temperature. 2,700K is the warm, orange-tinted light most homes use, around 4,000K is a neutral white, and 5,000 to 6,500K looks cool and bluish. If you light photos with household bulbs, use the same number in every lamp so you have one color to balance for.
What kelvin should I set for a sunset?
To keep the warmth you see, set around 5,500K or the Daylight preset, which records the sunset as warmer than neutral. Set 6,500K or higher to push it warmer still. Setting the camera to match the sun, near 2,500K, would neutralize the sunset and leave it pale.
Ready to plan a shoot around warm or cool light? Sunrise photography and twilight photography cover the two ends of the day, when color temperature changes fastest.