This is definitely the most stretched interpretation of the term 'derivative work' that I've ever encountered.
Developing a negative does not create 'a derivative work', since developing film is not 'interpreting' it in an original way, it for the most part is chemistry. Do it the same way twice you get the same result.
You can prove that to yourself by cutting a roll of film horizontally in half and then developing the two halves independently using the same recipe. If you do it all by the book they'll come out in such a way that the two film halves can be reconnected to give you the whole images.
Developing a negative does not create 'a derivative work', since developing film is not 'interpreting' it in an original way, it for the most part is chemistry. Do it the same way twice you get the same result.
You can prove that to yourself by cutting a roll of film horizontally in half and then developing the two halves independently using the same recipe. If you do it all by the book they'll come out in such a way that the two film halves can be reconnected to give you the whole images.