The kind of beamsplitter I was referring to is a special single-piece prism which splits
all three (or four) beams simultaneously. This kind of glass could be differentially
multicoated or used with separate filters. In other words, if someone had a lot of
machining capability, time, and money they could come up with a tricolor camera a lot
more sophisticated and precise than anything from the past. You would also want
registered vacuum film positions. Simple project in theory but nervewracking in execution. Would weigh a lot and probably no one will ever build one. Just a fun idea
I've long had. As for carbon printing, I believe it could also be modernized by thinking
outside the box, using a whole new class of pigments and a different tanning regimen
for the gelatin; but again, no one is going to have the time or budget to do this, let
alone a potential market for the materials. Sad. Such a beautiful process. What is being done with the older tricolor cameras typically requires a faster film for the blue
separation than for the red and green. Try 100TM for R&G and 400TM for the B. It is
easier to get matched separations with these films than with the older Super XX, which
had problems building enough contrast with the blue separation. Photoshop simplifies
things, but I have demonstrated to myself that very precise separations can still be made the old-fashioned way vis darkroom alond, indeed, much better than in the "good old days" themselves. Time-consuming to learn, however.