Originally Posted by chuck94022
These effects seem to be very tricky. If you remember the introduction of Fuji Reala film, with the "fourth layer," they were able to counteract unwanted greenish effects under certain fluorescent lights. Later films seemed to handle this situation just about as well without a fourth layer. So some very tricky interimage effects are going on. These are commonly attributed to things called "development-inhibitor reactors," known as DIRs or Super DIRs. (I only know of these things from technical papers or the very occasional discussion with film engineers.)
I don't know much about the split developers so I shouldn't talk about them, but it is my opinion that modern C-41 film developing is such a finely balanced process that any tampering is more likely to unbalance things than it is to keep them the same. Just guessing, though.