Copyright 2012 Andrew Dobson
Read the latest “So, You’re A Cartoonist” at the following [link]
This goes into more detail about my coloring process and how I deal with paint program's natural tendency to apply anti-alias to my work.
In Photoshop you can deselect antialias for filling in your colors. I recommend always deselecting antialias whenever possible unless you're trying to make the edges smooth and blurry or shrinking the image for the internet.
You can use anti-alias when filling in with the paint bucket to let it automatically "smooth" out the edges of the artwork, but if you need to change a color later it can be messy and time consuming, which is why I tend to let Photoshop worry about that later and leave my flats very simple easy to alter.
A user by the name of Alenonimo over on the SYAC site recommended that when reducing digital art in Photoshop to make sure it's set to Bilinear and not Bicubic. Bicubic is more for photographs, not cartoon artwork and Bilinear gives a better image reduction for those types of images. Thank you Alenonimo!
This is not the best way to color, nor is it the only way. It's my way and I think it's a very efficient method of coloring, especially when you have a large surplus of artwork to produce in a very short amount of time. I guess you could say it's very "animation" oriented, as I learned this process by making 2-D animation before the rise of Flash.