gimp - How can I map the colors in a greyscale image to a specific color gradient?

I’m attempting to add color to some greyscale icons (i.e. all three channels are identical). I want to map the colors such that the brightest grey becomes one specific color, the darkest grey becomes another specific color, and all the greys in between are translated into colors along the gradient between those two specific colors.

I’ve never used GIMP in this manner before and, while it looks like I should be able to use the Colors → Curves tool for this, I can’t figure out the specifics even after reading the docs and googling around a bit.

Answer

I think what you are searching for is called gradient map.

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  In Photoshop: Image → Adjustments → Gradient Map.

  
  


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  In GIMP:

  
  
  
  
  1. Select a gradient or create one in the Gradients dialog (Ctrl + G).
  
  
  2. Colors → Map → Gradient Map.