Steven - As far as a "charcoal effect" in your 35mm work, it might be analogous to that almost etched look I get with HP5 at moderate sized enlargements (up to 3X) from 8x10 film. But that is also related to the specific staining effect of pyro development and the resultant "watercolor grain" as we call it - smoothly blended, but with exceptional edge acutance.
At one point I had one of these framed HP5 prints on the wall adjacent to an exceptionally well done scraper etching on chalkboard, where black and brown ink is coated on the white chalk, and then the image scraped out with a sharp object. There was indeed a kind of visual affinity.
No, not the "soot and chalk" look that AA always condemned due to lack of shadow and highlight texture, but just a special look which can hover been graphic and photographic. Not "artsy" at all, but distinct. I have a lot of HP5 prints which give that impression.