Correct a photo's color cast

Where color casts come from

Your eyes adjust to the color of the light around you, so a room lit by warm bulbs still looks normal in person. A camera does not always adjust as well. The result is a photo that looks yellow or orange indoors, blue in open shade or on cloudy days, and sometimes green under fluorescent lights. Old prints and scans often drift too, usually toward yellow or magenta.

Mixed light, such as a window on one side and a lamp on the other, can even give two different casts in one photo.

How the correction is worked out

The tool combines two ordinary, long-established methods. Gray-world assumes the average color of a typical scene should be close to neutral gray, so it shifts the channels until the average balances. Percentile white balance looks at the brightest and darkest few percent of each of the red, green and blue channels and lines them up. Together they correct most everyday casts without making the photo look clinical.

When it has measured the photo, the panel tells you what it found, for example “warm cast removed”. That helps you judge whether it read the photo correctly.

It is a conventional edit, not a model. It does not know what the scene is, which matters for the next section.

Using Strength and Contrast stretch

Both controls preview live on a screen-sized copy.

• Strength, from 0 to 100, sets how much of the correction is applied. Full strength makes the photo neutral. A setting around 60 to 80 often looks more natural, because some warmth at sunset or by candlelight is part of the mood.
• Contrast stretch, on or off, also spreads the tonal range per channel. Turn it on for faded scans and hazy photos. Leave it off when the contrast already looks right and you only want the tint gone.

Photos that fool automatic correction

Gray-world expects a mix of colors. A photo that is genuinely dominated by one color, such as a close-up of autumn leaves, a green lawn, or a sunset, can be pulled away from its true colors because the tool reads that dominant color as a cast. For those, lower Strength or skip the tool. A quick look at skin, white paper or gray pavement in the result tells you whether it went the right way.

Scans of old prints benefit from Contrast stretch as well, because fading usually flattens the tones as well as shifting the color.

Press Apply to process the full photo and add a version you can compare against or undo.

What it will not do

• Photos dominated by one real color, such as foliage or a sunset, can be over-corrected.
• It applies one correction to the whole image, so mixed lighting, like daylight plus a lamp, cannot be fixed in both areas at once.
• It is a conventional edit and does not recognize what the scene is.
• It cannot restore color that has faded completely from an old print.

Devices and downloads

No download — ordinary image arithmetic. There is no model, so WebGPU and WebAssembly are not involved. The preview runs on a screen-sized copy, and Apply corrects the full-resolution photo in this tab.

Instant edit: Ordinary image arithmetic. No model, no download, works in any modern browser. See what is stored on this device.

Step by step

1. Open the photo. Drop, paste or choose the image with a tint.
2. Read the detected cast. Check the note that says what kind of cast was found.
3. Adjust Strength. Go lower if you want to keep some of the original mood.
4. Apply and export. Turn Contrast stretch on or off, apply, compare and save.

Questions about auto colour correction