Digital Illustration from Linework

If you are scanning in linework and want to create a color illustration from it, it is easy to do in Photoshop, here's how. Make sure the linework is on it's own layer. Set that layer's blending mode to multiply. Create layers underneath that layer and begin adding color. The lines will still show, but you will see the color underneath. If you want the lines to disappear, move your color layers above the line layer. Here is an example of an illustration created using this technique.

If you want to fill areas with color you can do that too. Choose the Paint Bucket Tool, and make sure the "All Layers" option is checked. Go to your color layer and fill. This method will keep the color separate from the line layer. If too much area fills, go to the line layer and close any "leaks" in the linework. Use as many color layers as you need, but it best to never add color to the linework layer. The reason is that each layer has it's own mask. By using color layers with a strategy, you automatically create selections that can be used for fine tuning your illustration later on.