Just to give it a try, I scanned a 7"x5" colour print at 360 dpi into
Photoshop. After cleaning up one or two intrusive objects (twigs etc) and
adjusting contrast, I printed 10"x8" CMYK colour separations onto the
transparencies at 720 dpi. There seemed to be a very good density range,
and I used them for four-colour gum on Bockingford paper (cadmium yellow,
Winsor blue, alizarin crimson and neutral tint), with results that I quite
like. The paper shrinks about 1% with the first wash, so needs to be
prewashed before the first colour coat to maintain registration.
Punch-and-pin registration was used - punching all four transparencies
together makes registration easy.
It doesn't feel like "pure" photography, but the prints are nice, and it is
a lot of fun!
best wishes,
Henry Rattle