Coloring line art in Photoshop • 1 Jul 2000
Raw scan I start with scanning my drawing at 1200 DPI, or even at a higher resolution. I plan on reducing it later. The image above is shrunk, otherwise it wouldn't fit on the page ;-)
Closeup This is a closeup of a piece of the raw scan. In this stage I also remove unwanted lines, stains, dust, ink blots etc. I find it convenient to do it now because they're very visible on a white background. I just draw over them with a white brush.
Every pixel either black or white I then proceed to convert the image to contain only white and black pixels. I pump up the contrast to +80 to make the black lines somewhat fatter, then I convert the image to Grayscale, then to Bitmap with a 50% threshold. I then convert it back to Greyscale (factor 1) and to RGB full color. I convert this 'background image' to a layer by choosing 'Layer, New Layer, Background from Layer' from the menu.
Select the white Using the 'Select/Color Range' I select the white area, with 'fuzzy' set to 0.
Remove the white I then press the Delete key to remove all white pixels. The black ones remain, without antialiasing (so it looks a bit ragged), but this will be corrected in the next step.
I downsize the picture (25% usually). Because of the 'Resample Image: Bicubic' option, the raggies disappear and become nice transparent black pixels.
Coloring I add a new layer, drag it below the line art, and add color with the Brush. Because of the transparent edges on the line art, the color blends nicely behind the line, without raggies or fringes. With complicated pictures I sometimes use multiple layers to add color and textures to part of drawings.
I shifted the color layer a bit to show you how it would look without the line art ;-)
The result The resulting image placed on a background. Again, the transparent black edges of the lines make it blend perfectly over any background.
A closeup reveals how the transparent black pixels blend in.