Hey Greg,

That fact that you don't treat a question like that as rhetorical is a testimony to your character.

OK, I think I fully understand what you're proposing now. You'd get just one of these films, and use it as a master to make smaller line rulings on a high-contrast film.

A short aside; so I found a biography of Herbert Ives and the above mentioned "Improvements in Diffraction Color Photography" [sic] was one of his graduate papers while at Cornell, IIRC. Same with a similar paper on Lippmann photography by him. I love imagining the period when stuff like this was cutting edge; being studied at institutes of higher learning. I guess that Professor Wood himself was the authority on color at the time, according to the biography I read.