Hi there. Both issues you mention raise copyright issues. Copyright refers to legal rights in original ideas or works that are protected in Australia under the Copyright Act 1968 (Cth). Generally these rights give the author exclusive rights to licence others in regard to copying the original work, broadcasting it, publishing it, etc. Depending on the nature of the work, copyright generally lasts for 70 years from the author’s death. Legal action can be taken against a person who infringes someone’s copyright, although these can be difficult claims to make.

In both of the scenarios you described, it appears that the artists’ copyright may have been infringed. With respect to the photograph, the photographer has copyright in the original photograph that will be protected under Australian law. Whether the photographer can take legal action against the private buyer will depend on the original terms of sale. You have said that the photographer did not agree to the reproduction of his image, which means he most likely did not assign his copyright to the buyer. The reproduction of the image on posters is likely to be an infringement of copyright.

A similar situation exists with respect to the sculpture. The artist did not agree to assign or licence his copyright in the sculpture. Because the merchandise has been derived from the original sculpture, the artist is likely to have a legal claim against the art gallery for copyright infringement.