Coloring Books for Adults
Although I have a problem keeping within printed lines
I found the online coloring pages usefull. When water leaks destroyed my antique botanicals I used online fern coloring pages to try and duplicate them. Put them on a light box, using water color paper, placed drops of water within the lines, then drops of water colors. Using colored pencils, especially water color pencils, I imagine the same effects could be obtained.
This is one of the group I did:
