I have a grey scale image, and I would like to map it to a specific color channel (red in may case), in gimp. That is, I would like to produce an image with only red channel, and that the red and non-red parts will be determined according to the grey scale image (black- no red, white - red). Alternatively, I can have all 3 channels in my image, but the blue and green channels should be black (that is, no blue/ green light).
How can I do it?
I found this post, but it doesn't answer the question, as it affects all 3 channels.