Quote Originally Posted by MattKing View Post
Wouldn't the RC substrate cause a bit of a problem?

I guess if you did this, it would be necessary to add an orange filter similar to the mask in C41 colour film.
Seems to me it'd be the same RC substrate as present on RC B&W papers.

While my understanding of C41 masking is a little shaky, I don't believe it's necessary in order to get a balanced exposure from RA4 - see the Rollei maskless film for example. The orange mask is not a uniform filter layer but rather a dye layer that gets produced during development to counteract shortcomings spectral sensitivity of the cyan dye. You can have maskless C41 film, it will merely have poorer colour accuracy.

However CTO (daylight->tungsten) conversion filter might be beneficial since RA4 is tungsten-balanced for use in an enlarger. Unfiltered use in daylight would (I imagine) hit the blue layers much more strongly than you want.