After I set the GIMP image preferences to 32bit floating point en using Linear Light, I created a new image. Then I set the foreground colour to R=50%, G=50% en B=50% and fill a rectangle with this foreground colour. To my surprise the Colour Picker tool now shows RGB values of 0.2140 instead of 0.5000 as I would expect because I am using linear colour. 50% is 50%. Since 0.2140 is the linear colour equivalent of 0.5 in the perceptual gamma space, it seems that GIMP treated my colour setting as a perceptual gamma number and converted it to linear light. Really strange. Why does the program think I started with Linear Light in the first place?

1 Answer 1


AFAIK the color picker doesn't display the values, you must be talking about the pointer tool display (Edit: I stand corrected)

When you set the color to RGB(.5,.5,.5) these are gamma-corrected values. "Linear-light" is about internal values and processing.

In the color picker and the pointer tool, there are various display options. The Pixel one shows the internal values (ie, RGB(0.2122,0.2122,0.2122) for the middle-gray)., the others are gamma-corrected when it makes sense (RGB(0..255), RGB(%), HSV).

enter image description here

Another place where you have the choice between linear and gamma-corrected values is the histogram.

  • No, I am talking about the Colour Picker tool and I have the option "Use info window" checked.. In the info window there is a drop down box where you can indeed select "Pixel", "RGB" and "RGB%" etc. Commented Apr 26, 2020 at 14:27
  • Ah, overlooked this... but this doesn't change the rest of the answer, the display options are the same, and the "Pixel" option shows the linear values.
    – xenoid
    Commented Apr 26, 2020 at 15:47

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