I generally don't have an issue with people using my art. I have no problem with people coloring my B&W art, or using my characters in their own art. The only things I ever ask are:
• Ask permission before doing so. I provide several ways to contact me so it's not hard to do.
• Let me see the finished product or give me a link to where you post it. I do this because I like to see what others can come up with or do, and also because I like to be able to feature it on my site.
• Give credit where credit is due. If you color my art either leave my signature on it or put text somewhere on it giving credit to me for the original art. If you use one of my original characters, same thing. I would greatly appreciate if you could put somewhere that I was the original creator of the character.
The only time I allow exceptions to any of this is when someone is doing gift art or fan art for me. If you're drawing a pic for me as a gift or surprise naturally I don't expect you to ask permission ahead of time. All other rules will still apply though.
I don't think any of this is too much to ask and I greatly thank those that are respectful of my art. I keep an eye out as best I can for art thieves and to anyone out there who does the same and let's me know, I especially thank you. You've helped me out alot in keeping my art safe. I don't take highly to art thieves and will do everything possible to make sure they are punished accordingly and that other artists out there are on the look out for those individuals.