Color Temperature Calculator

Color temperature describes the color of light on a scale measured in Kelvin (K). The term comes from physics: a theoretical perfect black-body radiator glows different colors at different temperatures, from dim red at low temperatures to bright blue-white at high temperatures. In photography and videography, color temperature tells you how warm (orange/yellow) or cool (blue) a light source is. Candlelight is around 1,800K (very warm/orange), midday sunlight is around 5,500K (neutral white), and a clear blue sky is around 10,000K (very cool/blue). Understanding color temperature lets you match your camera's white balance to your light source so that neutral gray appears gray and white appears white in your images.

Mired stands for micro reciprocal degree and is calculated as 1,000,000 divided by the color temperature in Kelvin. Mired is useful because it provides a linear scale for perceived color shifts. On the Kelvin scale, a shift of 100K near 2,000K looks very different from a shift of 100K near 6,000K. In mired, equal shifts produce roughly equal perceived color changes across the scale, making it the standard unit for specifying the strength of color correction (CC) filters. A warming filter might add 30 mireds (positive shift), while a cooling filter subtracts 30 mireds (negative shift). Gel manufacturers, studio strobes, and professional color meters all use mired values.

It depends on the type of indoor light. For standard incandescent or tungsten bulbs (around 2,700 to 3,200K), use the Tungsten or Incandescent white balance preset on your camera. For warm white LED or halogen bulbs (around 3,000K), Tungsten is also the correct setting. For fluorescent lights, use the Fluorescent preset, but note that fluorescents vary widely in color temperature from around 4,000K to 5,000K. The most accurate approach for indoor work is to set a custom white balance by photographing a neutral gray or white card under your specific light source, which removes any color cast regardless of the exact color temperature.

Open shade is lit primarily by blue sky light rather than direct sunlight. The sky acts as a large light source with a color temperature of around 7,500 to 9,000K, which is much bluer than direct sunlight at 5,500K. When you shoot in the shade with your camera set to a Daylight white balance (5,500K), the cooler blue light of the sky is not corrected, so the image takes on a blue color cast. Setting your white balance to Shade (around 7,500 to 8,000K) adds warming to counteract the blue sky light. The same effect is why portrait photographers often avoid midday shade without correction.

The difference between 5,600K studio flash and 5,500K noon daylight is very small: only 100K, which is less than 4 mireds (1,000,000/5,600 = 178.6 mireds versus 1,000,000/5,500 = 181.8 mireds, a shift of about 3.2 mireds). In practice, this is a negligible difference and not visible in most photographs. Studio flash is rated at 5,600K to match the Daylight white balance preset on most cameras. The slight variation means that when mixing flash with ambient daylight, the two sources will be almost perfectly matched, which is why flash was designed to that specific color temperature. Some flash units vary by several hundred Kelvin from shot to shot, which is a larger source of color inconsistency than the 100K nominal difference.