How to use white balance card with specific RGB values in gimp

[Liese]

(11-20-2021, 09:25 AM)rich2005 Wrote: That R=219, G=220, B=220 is a grey point.

To match that, use a sample point see: https://docs.gimp.org/2.10/en/gimp-sampl...ialog.html

Split a example for before / after   The color match card shows R=165 G=169 B=196



Adjust the colour curves. There are separate curves for each of RGB  Get the value R=219, G=220, B=220



You can save that curve and use it with other photos taken at the same session.
Of course, it can be a lot more complicated than this to match a complete range of colours.

Thank you so much for this helpful answer, I would have never figured it out on my own!