Color from a Photo or Camera
Upload a photo or point the camera, tap a point and get its color in HEX, RGB, HSL, Lab and CMYK. Set the white material and the readings are corrected for the light.
How to measure
- Aim at the print material (paper, film, board) and tap it.
- Press “Set white point (material)”.
- Measure the other colors: they are corrected against your white automatically.
Tap the picture to choose a point (arrow keys move it by a pixel).
Everything stays in your browser; nothing is uploaded.
More: area size
A larger area means less noise; stay inside one even surface.
Readings and ΔE(0 / 12)
Empty so far.
Honest limits: a camera gives only an estimate
- A camera is not a spectrophotometer: it gives an approximation, not an exact color.
- The result depends on the light, the auto exposure and the camera's automatic white balance.
- To compare, keep the same lighting, with no flash and no glare, and lock the exposure where you can.
- Only an instrument measures an exact color.
How it is calculated
The area around the point (1, 5×5, 11×11 or 31×31 pixels) is averaged in linear RGB: the sRGB values are turned into linear light, averaged and turned back. So a mix of black and white gives the right 188, not 128.
White balance: the picked white (paper, material) becomes the reference and each linear RGB channel is multiplied by 1 ÷ the white's channel. The white then equals 255, 255, 255 and the other colors shift the same way.
The color is shown as HEX, RGB, HSL, Lab (D50 or D65) and a simple CMYK. The CMYK is approximate: an exact color needs an ICC print profile. The difference between readings is ΔE76 and ΔE2000 in Lab D65.
linear = ((sRGB + 0.055) / 1.055)^2.4 mean = (sum of linear values) / number of pixels corrected = mean × (1 / linear white)
Worked example
A black and a white pixel (0 and 255) average to 188 in linear light, not 128.
A white paper captured as 236, 214, 168 equals 255, 255, 255 after the correction, and every other reading on that picture shifts with it.
An estimate: the camera, the light and the screen distort color. Use an instrument for a color that matters.
Check a PDF