This question has been frying my noodle for a couple days. On my Focomat iia (which I havent used yet) there is a slot for format masks which is below the neg and above the lens. Rather then using a below lens filter rigup I can just slide filters in the format mask slot. I feel that this is essentially the same as an under the lens filter. IS this true?
I think the best place is above the neg, out of the optical path, for best sharpness, an option you may not have. If used one of the two ways you describe, keep them in great shape.
Yes that is the one except the one shown in the color versions which had a filter draw. I read an account where the working prints are done with the below lens filters then for the final prints they put a gel on top of the condenser. Interesting but since I split grade often this would not be feasable. Thanks for the comments
Actually, I have used split filtration with an old Leitz Valoy by removing the lamp housing and placing filters on the condenser. It wasn't really that difficult to do with the Valoy after getting used to the procedure.