Quick question, I'm having a documentary made about my show and there is a bit where we talk about the history of Mentalism. I'd like to have some pictures of Mentalists on screen while we're talking about this. Older Mentalists, like Stuart Cumberland for example. In my mind I imagine pictures similar to the picture on the front of Mentalism wikipedia page.

The question is, does anyone know if these pictures are public domain? I'm not sure how these things work with pictures and we don't want to step on any toes.

Just be safe and put a photo credit in

Maybe I misunderstand your answer, but I don't think it's safe or legal.

Copyright in photographs remains with the photographer (or his estate) for 70 years after his death. So I imagine most or all of the photographs you are considering are still subject to copyright.

Mike