How do you create a protective mask?

[u/3Dcaunyd]

I been doing all kinds of video watching and tutorials, and this simple question is driving me up the wall. Im using term masking as in the classic masking of something so it doesn't get painted over, like you might mask something with masking tape and paper.

https://www.google.com/books/edition/Batman_Vol_6_Graveyard_Shift/aDGNBwAAQBAJ?hl=en&gbpv=1&printsec=frontcover

I've tried all manner of Gimp masks, painting, white, black, etc. In my picture link, I want to paste in another picture of batman, but because he is cut and pasted in from another picture, I want to be able to blend white/yellow area around him vigorously so that it matches the linked picture's background. So the goal of my mask is to protect the black batman silouhette so I can't accidentally draw on him while trying to change the colors around him.

Thanks for your input!

[u/ofnuts]

You make a selection. But in image editors, the selection is where you can alter things when you paint, what is outside the selection is left untouched. So you probably want to invert the selection before painting.

[u/3Dcaunyd → u/ofnuts]

I've also tried to cut the black areas out myself with the fuzzy tool and just work on the targeted area around what was cut out, and the problem with that is, again Im able to blur colors into the transparent space where the black was cut out. Maybe if I just cut the image completely, so that there isn't a transparent space where the black used to be? Dont know how to do that though, been trying.

[u/3Dcaunyd → u/ofnuts]

I tried do this. I selected the black area and put a layer mask on it, with the option "selection" and it just cuts out the piece that I want masked, but it is very strange, when I try to paint on a color on the white thumbnail, purple for example, on the background, it doesn't paint purple, it paints transparency. And if I switch to the original thumbnail, where the Black parts have been cut out, I can blur and change the borders of what is protected. Again Im looking for a mask that protects the original black parts. At least doing this hasn't worked. Thanks for your response

[u/ofnuts → u/3Dcaunyd]

I didn't mention a layer mask... A layer mask is a totally different animal used to selectively alter the opacity of the layer. The "protective mask" you want is a plain selection mask.

Now, for what you want to do, you can use a different technique that involves a layer mask to cut out the silhouette by erasing around it (painting black in a layer mask is the same as erasing on the layer). However since there is now an anti-erase mode on the Eraser the layer mask is a bit less useful and you can just use the eraser.

[u/NicholasCureton]

Are you trying to remove dialogue texts from the comic? Or you just want to paint something but you don't want to paint some area.

First one is quite simple. Make a selection and fill it with white.

Second one is also simple but a bit more work.

Select the area you want to protect.

Copy and paste as new layer.

Now you have perfectly fine area which you want to protect.

So we now have 2 layers. Original layer and copied piece of layer.

Now you can paint on original layer without affecting protect (or copied) pieces of layer.

If I've to do that, I'll use new layer for painting under the copied piece of original layer. In that way, I can easily remove add paint if I wanted to without touching both original layer and copied layer.