So here's what I am trying to do:
I have a picture (of a cell phone actually) and I need to create transparent areas where the backlight would be visible (around keys, numbers on keys). I could do this by selecting a color with alpha 0 and pixel by pixel fill in the backlight areas with transparent. This kinda works, but gives me very jagged and harsh edges to the backlight area (the backlight is generally 1 or 2 pixels wide). I need the transparent sections to be alpha-blended and/or antialiased into the image somehow. Using Gaussian blur pixel by pixel helps a bit but really just makes the whole backlight/image fuzzy and is VERY labor intensive. What I think would work was if I could select a transparent color for the Adjust Color tool, but that doesn't seem to be possible.
Any ideas?
