"Is it possible to make prints of other people's work if you have the original? Or could only the original artist do this?" -- Bernie
Unless you've bought the copyright of the painting along with the physical painting, the copyright remains the artist's and they retain the exclusive right to make prints from it. In the same way buying a CD or book doesn't entitle you to make copies of it.
How do you know if you've bought the copyright? I'd expect it to be in the form of a sale letter or certificate saying copyright was transferred, and for it to be signed and dated by the artist. A Certificate of Authenticity does not grant you the copyright unless the wording on it specifically says so.
See also: Artist's Copyright FAQ: If I Sell a Painting, Do I Lose Copyright?
Go to Full Artist's Copyright FAQ.
Disclaimer: The information given here is based on US copyright law and is given for guidance only; you're advised to consult a copyright lawyer on copyright issues.
