Illustration contracts are essential. Be sure to review your contract carefully. There is a big difference between a license in an assignment of artwork. Know which one your contract contains.
Assignments: In an assignment, the illustrator transfers the art work and any rights of ownership over to you for good. You, the author, will then have full ownership of the artwork and in the copyright, thereby allowing you to use the art whenever and however you please. This can also be termed as a “copyright transfer.”
Licenses: In a license you are more or less renting the artwork from the illustrator. The illustrator retains full ownership and copyright to the art and gives you permission to use the art for a limited time and for a limited purpose. Once the license expires, you as the licensee can no longer use the art.
Look for a Reversion Clause. Reversion is when something occurs that causes the rights in the artwork to revert back to the illustrator, As you might have guessed, reversions mostly occur in licensing agreements. The illustrator grants the author license to use the artwork until a specific date or until a specific event occurs. When this predetermined date or event occurs, the rights terminate and flow back to the illustrator.
I’ve encountered way too many people who did not read or understand their agreement. Some thought they owned the artwork, when all they had was a license for use.
So read your illustrator contract carefully, and know exactly what you’re getting for your money. If you don’t understand, have an attorney in your area review it for you.