You mention colors not being copywritable because many programs use them. This is true. Poser light sets, in particular, are not used in anything other than Poser. I think it mainly boils down to this: you can not copyright settings of a feature that is completely native to the program. The light settings can not be used in any other program. If you could add original lighting, then you could copyright those. How could you enforce a copyright on a set of settings? It is possible, and probable, that someone would duplicate the settings completely at random. If you were the one to do this, would you like a copyright suit brought against you even though you had no prior knowledge of these settings? That doesn't mean you can't sell your settings, you just can't copyright them as it would be unenforcable.