[Old-N-Feeble]

Ah, if only one could do it for 35mm... (Well, I'm sure one could, but somehow life is too short. Maybe if I was younger [and foolish enough to do it {considering the things I found time for when I was younger Vs the things I should have been doing}]).

Youth is wasted on the young. Wisdom is wasted on the old.

I don't see why you couldn't do it for 135 format. You just couldn't be "quite" as precise with it.

And what's the fun of being young and wise... wisdom puts a real damper on sewing those wild oats.

EDIT: I've been searching and there's quite a bit of information regarding masking above the film but I haven't yet seen anything about using color to take advantage of multi-contrast paper to adjust local contrast, e.g. add more contrast to the sky. I know that contact masking with registration pins has been around for many decades as a way to improve acutance but that's a royal PITA.