Quote Originally Posted by Falconius View Post
how does one determine what that copyright is actually worth to the one selling it?
That is the key issue. We as creators need to be able to guess how a client is going to, and is able to, exploit the work economically.
AND how the rights you are giving away prevent YOU from exploiting the work commercially.

The more the client is going to (or is potentially able to) use the artwork, the more value the copyright has.
The copyright for a privately commissioned piece (let's say a DM who wants a decent map for their campaign) is definitely worth less than that of a piece for a publisher or an advertising agency.

For example, if I make an illustrated map of Italy, I personally might not have many uses for it, but a publisher who wants the copyright can then use it in endless books (think of publishers like DK), even sell it further to third parties.
This means it has GREAT value for them, and should be charged accordingly.