how do i copyright a cartoon?

[skyrich62]

Some of the other people are correct. Copyright is automatic, as long as you can establish and prove that the *expression* of your idea, (note, not the idea itself), is yours and yours alone.

It's best to add a notice to your work which specifically states that you are claiming your rights per copyright law, like this:

Copyright © Skyrich62, 2013, all rights reserved.

This notifies the public that you are *not* putting the work into the public domain, but are reserving all rights to yourself. Strictly speaking, this is not necessary, but it does help your case if you ever pursue a copyright infringement suit.