I have a line drawing which I've scanned in and am using in paint.net. I'd like to apply a repeating pattern to particular parts of it. I have created a pattern in a second layer and repeated it with Layers/Repeat/Zoom/Tiling. Now the pattern appears across the whole of my image, understandably. So I need to delete it in places. I've tried the eraser but all that seems to do is grey it out, not erase it. Why on earth is that? I've also tried the paintbrush, selecting a colour of zero opacity. All I want to do is set most of the new layer back to the invisible colour, surely? But this has no effect.
Also, is there a way to select the area in the line drawing where I want to apply the pattern automatically? I've tried the Magic Wand, and that can clearly identify it because all of my lines start flashing. But beyond getting them all to flash I can't for the life of me figure out what I'm supposed to do.
Thanks for your help.