Lightroom: Wrong LAB values in LR5.2?

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  • Updated 5 years ago
  • (Edited)
I try to work with LAB values in LR5.2.
The expected values shown by Ligthroom do not match.

Expected value for blue: L=0, a=0, b=-90
Result in LR: L=29,6 a=68,3, b=-112
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André Roßbach

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  • confused

Posted 5 years ago

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Eric Chan, Camera Raw Engineer

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Why are you expecting the color readout for a "blue" color to be exactly 0, 0, -90? Did you create this specific blue value in Ps or another image editor?

For example, the reference Lab value for the blue patch of a ColorChecker 24 chart is 29, 14, -50 ...

It's very unlikely that most "blue" colors that you photograph would have exactly (0, 0, -90) Lab values ...
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André Roßbach

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Yes Eric, I have a reference image with the corresponding lab value.
But I have no experience with LAB.

Thank you, ColorChecker is a great tip!
The LAB value of the blue ColorChecker patch is 20, 27, -72.
For green 60, -42, 40 and red 45, 63, 39.