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I would like to use the grey patches row of my X-Rite ColorChecker Classic to set correct exposure in post processing, but I can't seem to find the data for the chart on X-Rite website or elsewhere.

Are these values public ?

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The reference data contains the CIELAB data for the following colour rendition charts:

  • ColorChecker Classic before November 2014
  • ColorChecker Classic after November 2014
  • ColorChecker SG before November 2014
  • ColorChecker SG after November 2014

The formulation has changed in November 2014, so you must check which version of the chart you are using. Keep in mind that the pigments are stable only a few years, especially after long sunlight exposition, and that X-Rite recommends changing them every two years.

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The data can be downloaded here — it is not quite spotlighted, but there is a "Colorimetric data (PDF)" link in the product description on xritephoto.com (under the "Specifications" tab).

Note : according to the link in Kel Solaar's answer, these values are obsolete since they correspond to charts made before November 2014 and pigments are not supposed to be stable that long.

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  • What's really odd about that pdf is the colours actually in it are nowhere near the claimed figures. I have one from another [unknown] source which is within one on every single colour on my displays.
    – Tetsujin
    Aug 15, 2020 at 15:59
  • @Tetsujin I assume you are talking about the pictures patches in the PDF, not the actual values, right ? Indeed they seem quite off, in particular the red channel (I checked with gimp's pipette), which seems quite ironic for a color management company. Unless they did mix colors on purpose to avoid having people just print the picture rather than buying the chart ?
    – Skippy le Grand Gourou
    Aug 15, 2020 at 16:13
  • @Tetsujin Do the numbers at least match yours ?
    – Skippy le Grand Gourou
    Aug 15, 2020 at 16:14
  • I didn't examine every one, but they seem to, within 1. I also just realised that in the pdf, the colours above don't match the ones in the table either.
    – Tetsujin
    Aug 15, 2020 at 16:18

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