Turning comic line art into full color
This might be of some interest -- the link leads to a tutorial by a comic book colorist detailing how he took a piece of line art and turned it into a full-color cover using Photoshop. While the techniques are specifically geared for a four-color print process rather than just an image viewed on-line, there's plenty of tips that should prove useful.
http://www.livejournal.com/community/scans_daily/782553.html
http://www.livejournal.com/community/scans_daily/782553.html
