Free ColorChecker Chart

What is a ColorChecker?

A ColorChecker is a standard colour reference chart used in photography, cinematography, and colour science. The original was developed by Macbeth in 1976 and is now sold by X-Rite. It contains 24 carefully defined colour patches — natural colours like skin tones and foliage, saturated primaries, and a neutral greyscale ramp — each with precisely measured Lab values.

Because the Lab values are device-independent and published, you can use a digital version of the chart to verify that a LUT, colour profile, or grading tool is handling colour correctly. If the grey patches stay neutral and the skin tones look accurate after applying your grade, the colour science is sound.

What the 24 patches represent

How to use it for LUT testing

1. Download the PNG above and upload it to your colour grading tool
2. Apply your LUT or colour grade
3. Check the bottom row — the six neutral patches should remain free of colour casts. Any tint indicates a white balance or tonal issue in the LUT
4. Check the skin tone patches (top-left two) — they should look natural, not orange, green, or magenta
5. Check the primary patches (row 3) — reds should be red, not orange; blues should be blue, not purple

For log-to-Rec709 LUTs specifically, the chart should look like a normally exposed image after the transform is applied. If highlights are blown or shadows are crushed, the technical LUT needs adjustment.

How this chart was generated

This chart is generated programmatically from the official X-Rite ColorChecker Classic Lab D50 reference values, using the standard Lab → XYZ D50 → XYZ D65 (Bradford chromatic adaptation) → linear sRGB → gamma-corrected sRGB pipeline. Each patch is a mathematically exact 120×120 pixel block with no JPEG compression or colour profile embedding. The result is more colour-accurate than most downloaded images, which are often JPEG-compressed or have embedded ICC profiles that shift values when opened in different apps.