I've been doing some color addition to old black and white photos.
Its been interesting. Most of the time about halfway through you want to just give up cuz it looks like this:
It takes a lot of time getting the shades in the face right and often you have to work with the saturation up all the way just to see what's going on.
It's kind of like tayloring a suit. The thing looks like a second grader's been at it with pinking shears and some chalk till its finally all finished.
Two or three hours and 46 layers later I had better results.
There's more of these on my image restoration page.