Hey, if you look really closely, you can still see bits of the blue sketch in very faint cyan.
Okay, so you've drawn a really cool character, roughly sketching it in with a light colored pencil, and then inking it. You want to scan it in and clean it up, maybe to color it or ready it for print. Or maybe, you doodled a really fantastic picture, but did it on the nearest thing at hand -- notebook paper with blue lines on it. How do you clean up a scan and get rid of the colored lines underneath the art?
| Scan in your art. As you can see, I've accidentally scanned this in upside-down (I do this a LOT), and there's a lot of miscellaneous stuff in here I don't want in my final image. | |
| So, I flip it around so it's facing the right direction. | |
| Next, I erased the bad attempt at Greek lettering, by simply painting over those parts with white. Now, I'm cutting the image down to a reasonable size using the crop tool. No sense in keeping all that white space. | |
| Much better. | |
| Now, I duplicate this layer, so I can mess with it a lot. | |
| And I create a new layer, and fill it with white. I put this one below my new copy of the scan. | |
| In the new, copied scan layer, I go into the Color to Alpha filter. This is a wildly useful filter, for many reasons, because it can select a color and strip it out of an entire layer - WHAM! | |
| I fiddle around with the color until I find a shade of blue that gets rid of as much of the sketch lines as possible, then click OK. | |
| Then I go ahead and merge this layer down onto the white layer. | |
| Oooh, ahh. Hey, if you look really closely, you can still see bits of the blue sketch in very faint cyan. | |
| That's nice, but really, I'd like this to be in greyscale now, not that strange brownish-maroon color. So I desaturate it. | |
| Voila la grayscale. | |
| When I zoom in here, I can still see traces of the sketch, as well as scanner cruft and dust and whatnot. That has got to go. So go into the Levels dialog. | |
| To darken my darkest areas to true black, I scoot the black pointer further to the right on the scale. To blow out the whites and get rid of the dust and crufties and leftover sketch marks, I move the white pointer to the left on the scale. And to mess around with my midtones, which I'd really rather treat as part of the lineart in this case, I move the grey pointer around, and decide to move it a bit to the right to darken up the lines a bit more. | |
| Lookin' good! But, is it *really* as clean as it looks? This is where the obsessive-compulsive tendencies kick in. | |
| I select the "color select" tool, and set the threshold to zero. Whatever pixel I select, it will then magically select every pixel in the image that is *exactly* the same color as the one I selected. | |
| I select an area that I'm pretty sure is really, really white, and look at the pattern of the marching ants. Hey look! Off there in the top left corner, there are some ants crawling around an area that I *thought* was white. | |
| I invert the selection, since I don't need to mess with the parts that I know are white. Then, I use my trusty white paintbrush to paint over the suspicious area. There, now it is really, really clean. | |
| And, the lineart is cleaned up and ready for whatever the heck you want to use it for. | |