I have tried researching this question and thought maybe I could get some help here. My father passed away a few yesrs ago and he had hundreds of old car racing NEGATIVES and photos, he was a photographer and had his own darkroom. I sold many of his shots that were negatives to many different people. I recently posted a few of his photos on a car racing website to show his work and someone who had bought some of his negatives was upset that I posted some photos. When I originally sold the negatives I put a note with them saying they were free to use them as long as they acknowledged my father as the photographer of the photos. I did not release any copyrights, etc..to the negatives, as I said I told them they could be used however they wanted with the acknowledgement. All the negatives were prior to 1978, all are from 1940's to 1960's. I would like to post some more of his work, I am not charging anyone for the photos.
I didn't find the right solution from the internet.