Change an Image's Colour Temperature
Warm a photo toward candlelight or cool it toward overcast daylight, using the actual Kelvin scale rather than an arbitrary slider. The multipliers come from a blackbody radiation approximation normalised at 6500 K, so numbers below that warm the image and numbers above it cool the image.
Drop images here
Multiple files allowed
The scale runs backwards from intuition
Low Kelvin values are warm and high values are cool, which is the opposite of how the words are used about weather. It's a physical scale: heat a piece of metal and it glows red, then orange, then white, then bluish. So 1900 K is candlelight, 2700 K a domestic bulb, 3200 K studio tungsten, 5500 K midday sun, 6500 K the neutral reference, and 9000 K+ deep shade under a blue sky.
6500 K is the no-op. Setting anything below it makes the image warmer; anything above it makes it cooler. Strength scales the whole adjustment toward neutral, which is how you get a subtle correction out of an extreme number.
Correcting versus grading
Correcting means removing a cast that shouldn't be there. A photo shot indoors under tungsten lamps with a daylight white balance comes out orange; cooling it toward 8000–10000 K neutralises that. Shade and overcast shots come out blue and want warming toward 4000 K. Aim for whites in the image looking genuinely white.
Grading means adding a cast on purpose. Warm for nostalgia, comfort, sunset and interiors; cool for night, clinical, technological and melancholy. Here you're not trying to make whites white — you're trying to make the image feel like something, and 20–40% strength usually reads better than the full move.
One honest limitation: this multiplies the whole image by fixed per-channel factors. That's exactly what temperature adjustment is, but it's not a full white balance — a raw converter also compensates the green-magenta tint axis and works in linear light before any tone curve. For a JPEG or PNG that's already been processed, channel multiplication is what's available, and for moderate corrections it looks right.
Related: Duotone and Gradient map for stronger colour treatments, Saturation and Contrast to finish a grade.
FAQ
Which direction warms the image?
Lower numbers. 3200 K is warm, 10000 K is cool, 6500 K changes nothing.
Why do the highlights lose detail at extreme settings?
Warming multiplies the red channel above 1, and values past 255 clip. Reduce the strength, or lower brightness slightly first to leave headroom.
Can I fix a green fluorescent cast?
Not properly — that's a tint problem on the green-magenta axis, not a temperature one. Hue rotate by a few degrees sometimes helps, but a proper editor is the honest answer.
Is transparency preserved?
Yes, only the colour channels are scaled.