Right, but you mentioned grain, so I figured you were talking about the cinematography. Sher, as far as I'm aware, shot Joker on ARRI Alexa 65--same camera he used for Godzilla as well, I think. I've never really considered Sher inspired by Chapman's work, but I know the Phillips was drawn to doing a character study, which really aren't made all that much anymore, at least for a wide audience. Only PT Anderson and Aronofsky come to mind for current directors who get their material out for wide release.
I believe Philips mentioned he wanted people to actually see his movie, and just basing it on a comic book character was the easiest way to do that. I think Joker would be as well received without the comic book trappings, but I highly doubt we'd see so many threads about it.
