The RGB values in Adobe DNG editor are very odd

[RDoc]

I'm trying to do accurate color for reproducing paintings. As part of all this I photographed a Color Checker Passport centering the histogram, then after converting the RAW into DNG using Photoshop RAW I opened in the the Adobe DNG Editor to create a profile which works quite well although not perfectly.

I noticed though that the RGB values displayed in the Color Tables display look very odd. Specifically, patch 1, "dark skin" shows an RGB value of 14, 10, 7. That's almost black, but shows on the screen as a normally exposed dark skin color. All the others have similar dark values, the first white patch is 109, 109, 105, the black patch is 5, 5, 5. FWIW the first path LAB values are 25, 9, 5.

Does anyone have any thoughts on what these numbers are? I haven't been able to find much documentation on this package on line.

[madmanchan]

Those are the linear scene-referred RGB values of the patch with ProPhoto RGB primaries, but in a linear gamma encoding (this is why they are dark, or much closer to zero).

[RDoc]

Ah - thanks for both the explanation and for the DNG editor itself. It's really useful and a lot of fun to play with, plus I find its profiles to be more accurate than the XRite ones, sometimes startlingly better.

However, I'd like to request that if, and hopefully when, you guys do another version that it allow users to set up different color spaces so the numbers could be directly cross referenced to PhotoShop and other applications.

[Tim Lookingbill]

If you're on a Mac, you can use the DigitalColor Meter set to Lab. Its readouts are gamma encoded except through your display's gamma which if calibrated to 2.2 gamma isn't that far off from what you're seeing.

You can check a DCM Lab readout from DNG Editor by entering the Lab numbers in a new document in Photoshop using its Color Picker which has Lab entry. You might have to convert the new document to your monitor space before you create the color in Color Picker. Not sure on that, but you can always convert to any other space to see if the Lab numbers change or the preview changes.