Regarding the negatives, I once used the harmonizing process that is in
Photographic Facts and Formulas (bichromate bleach, redevelop in
non-staining developer) to change the scale of a Polaroid negative, then
copper toned it. The negative looked really incredible, and gave a
rather wonderful print on silver paper. I would think this might work
well with uv processes as well. The color of the negative was well into
the brown range.
Larry Bullis
Skagit Valley College