There's a good post on the process of inking right now over at Comics University. In it, Jonas Diego, the inker, explains how he works and how inking fits into the creative process of putting together Lola: A Ghost Story. Here's a sample of what Diego has to say:
"With Elbert’s pencils I don’t go immediately to inks.
I spend some time figuring out the intent for a particular page via a script I was provided with. After that I spend some time with a blue Prismacolor pencil adding elements which I feel will help in the storytelling, setting up shadows to help create the mood and ambiance the scene needs, and correct some details in the art.
It is only after accomplishing this that I start inking over the blue lines."
Too often, I think we overlook the contributions of inkers, letterers, and colorists to the process of creating a narrative in comic form. Posts like this one are a good reminder of these kinds of important collaborations.