I'll give a scenario. Let's say I scan lineart and insert it into gimp like the photo above. I want to make the outline of the hair one color and the outline of the rest black like the drawing on the right. In krita, I can alpha lock so I can physically color just the outlines without coloring in any other layer. Can I do something like that in Gimp?
I see. Something similar to the video but on line art that was scanned rather than outlines drawn in gimp. Is it the same process?