I have seen a fair amount of hand coloring. I have seen Jill enfield work and teach others - whe has a book out on the techniques.

But, this site shows one photographer who really goes the extra mile in the process. She pays far more attention to detail and process than any other photographer that does hand coloring. I especially found it interesting how she collects and keeps samples of subject matter for later coloring.

Her name is Denise Ross. I am providing a link to her technical process description. If you go to the Home page, you can work your way thru many online portfolios.

http://www.dwrphotos.com/Support/About.Art.htm

-R