I want to change the exposure on like 20 layers all at once. I thought the "layer group" feature should be the thing to use, but when I group all these layers together, all "color" options are greyed out when I select the group. I'm still only able to affect one layer at a time.
Is there any other GIMP feature that will help me do this instead?
You could try the gimp_gmic_qt plugin.
http://www.gmic.eu
It has many colour filters, not specifically exposure but you should find one that is equivalent and can be set to apply to all layers. example:
One layer at once in GIMP!
I concur with rich2005, G'MIC will do the job, once installed, in GIMP menu > Filters /G'MIC-Qt
(08-29-2021, 07:17 PM)Speusippus Wrote: [ -> ]I want to change the exposure on like 20 layers all at once. I thought the "layer group" feature should be the thing to use, but when I group all these layers together, all "color" options are greyed out when I select the group. I'm still only able to affect one layer at a time.
Is there any other GIMP feature that will help me do this instead?
If the layers are all the same size (elements of an animation) put all the layers in a single "sprite sheet" that you edit, and then split the sprite sheet back to layers. See for instance my
ofn-layer-tiles script for the layers ⬌ sprite sheet transforms.