Lee -Originally Posted by leeturner
Sorry for the delay - computer problems. Yes, the discrepancy is in order to equalise the exposures as far as possible from grade to grade. With single colour filtration your exposures will typically be much shorter in the mid grades than at the extremes.
For split printing single filters are perfectly adequate. On my colour head I simply use 200Y and 170M, the maximum in each case. If you're using Ilford filters, just choose grades 00 and 5.