Ok this is pretty basic but I think I should put this out there. I'm doing a lot of reading on starting a t-shirt business and well I've come across some interesting facts about copyrights and licensing.

Copyrights

1. Once you draw someting or write you have the copyright automaticaly. As long as you keep original you can prove this.
2. If you sell this artwork to someone. You still own the copyright. they might have paid you to own that peice of art, but they do not own the rights to do what they want with it. example. I buy a drawing from person A, I hang drawing on my wall. Everything is fine. I decide I want to print copies and sell them, hell I own original. Wait stop person A still holds the rights. I can't legally do that.
3. Sign and put a little C in a circle the Copyright symbol. on your art to make it official. You can always file your copyright with goverment to make it more so.
4. If someone uses your art to make some money , and you have not given them the right you are intitled to be able to sue. The Catch. If you only haveyour art to prove its yours, you can sue for damages (what they made off your art) If you have filed a copyright with the goverment you are entitled to sue for $50,000 and lawyer fees.
5. If You buy someones art make sure if you plan to buy the rights as well when you purchase. Or work out a deal with artist to give royalties.

Licenses

1. in order to reproduce a trademarked or copy written item you must get licensed to do so.
2. I want to make Superman Shirts to sell to everyone, I need to get the license to do so from Warner Brothers. I want to make one personal t-shirt for myself , maybe a few more for friends. They might not care cause i'm not making money from it.
3. Drawing a copywritten character on commission. My friend is paying $20 bucks to draw Batman. Thats ok cause you are not mass producing it to sell. I think the limit is 10 copies. I can take 10 Copyies and sell them , no problem, if its my art to sell. Now I draw Batman to put in a coloring book, now i got problems,I better get a licence to do so.

There is a little more to it but those are the basics.