@Storel: Well, actually.. that doesn't matter, does it? Money being exchanged just usually signifies relinquishing his rights to it. The difference between "I am giving/selling you this DVD" and "I am letting you watch my DVD". In the latter case the person being lent the DVD doesn't really have a leg to stand on if you snap your own disc.
Well, if you give somebody money so you can watch their DVD and you have to return it when you're done, then the DVD has been rented, not sold. Selling entails a permanent transfer of possession, while renting entails a temporary one. You usually have considerably fewer rights with something you're renting than with something you own, as specified by the local laws (city, state, or nation) and/or any rental contract you may have signed.
According to some European copyright laws an artist has moral rights in a work that remain in place even after it's sold.
Yeah, but then it's a case of selling the rights to a work, but not the right of alteration. Basically a limited sale, but since the artist has ceased owning the work that wouldn't grant them the right to alter it. Their remaining not-sold right being "Well, you can't either!", pretty much?
That's an interesting point. With works of art, unlike most other things you can buy, it's generally understood that owning one gives you the right to do pretty much anything with it
except alter it (apart from restoration work on an old or damaged work, of course, and that's not so much
altering as
repairing; you're trying to return it to its original appearance, rather than changing that appearance to something else). As you put it, all the rights to that work except the right of alteration were sold with it. It's also generally understood, though, that the artist doesn't keep the right of alteration for themselves; they don't have the right to come into your house or museum and alter the work. So the right of alteration basically ceases to exist when the art is sold to someone.
Unless... the local laws give the artist specific rights after sale, as IICIH mentioned. OR
unless... the sale contract (oral or written) specifies that the new owner, or the artist, gains or keeps the right to alter the piece of art -- there's always an "unless" when it comes to contracts -- and the local laws don't forbid that practice. But I believe that's pretty rare.