Re: light washes out text AND noise in photoshop not in ST
Posted: 06 Mar 2012, 13:55
When I say "robust", I mean a script that will provide the results you want over a diverse set of inputs. I have only done a little work with Photoshop scripts, so you probably know more about them than I do -- I would have thought the "magic wand" tool would be something you couldn't script, since (as I've used it) it requires manually drawing a rough line around the region(s) you want to select.
The problem I foresee with a scripted color selection solution is that any color which is likely to be showing through from the back of the page is also likely to be present on the front of the page. You may imagine this problem can be overcome because "the show-through color is less saturated" or some such rule, but at the level of the pixel I don't think this will be true. At the edges of every solid-colored area on the front page you'll have unsaturated pixels, because the camera is averaging a bit of the color area and a bit of the white page to produce a single set of RGB values for that pixel. If you subsequently select these edges and clip them to white, you'll be getting "jaggies" which may be as annoying as the ghosting.
The problem I foresee with a scripted color selection solution is that any color which is likely to be showing through from the back of the page is also likely to be present on the front of the page. You may imagine this problem can be overcome because "the show-through color is less saturated" or some such rule, but at the level of the pixel I don't think this will be true. At the edges of every solid-colored area on the front page you'll have unsaturated pixels, because the camera is averaging a bit of the color area and a bit of the white page to produce a single set of RGB values for that pixel. If you subsequently select these edges and clip them to white, you'll be getting "jaggies" which may be as annoying as the ghosting.