You could argue that there is nothing on the canvas when the artists begins and nothing on the photographic paper as well. They both place their art on the blank sheet, thereby both are additive. The subtractive part is when the photographer's lens crops out what he wants to take back to his darkroom, the same way the artist crops in his head, what to place in his empty canvas. Most painters paint scenics or portraits and when they stare at the scene before laying down paint, they are subtracting as much as a photographer.
I would say the only person who truly subtracts is a sculptor who removes material to find the art underneath.
I don't disagree. In fact I like that idea too.
Mark Barendt, Beaverton, OR
"We do not see things the way they are. We see things the way we are." Ana´s Nin