exr manipulation

[rich2005]

Quote:..just to be sure. i don't want to change the color of the whole image, but only the painted parts...snip

Yes, looking increasingly complicated to give an answer without a good example image, however

You can add a coloured layer on top and create a layer mask from a selection Layer -> Mask -> Add layer Mask then From selection. The advantage is, if you save as a Gimp .xcf, you can change the colour and the mask at a later date. Maybe this is where the composite layers and mask comes in.

Alternatives, same selection and the Hue-Chroma filter.