O.K. so by reusing a litre of chemicals I can get 24 sheets of 4x5 film with the increased times for each batch after the first (re-using the full 1 litre of chems ),but if I use smaller vols prorata ( 250ml for 6 sheets, 500ml for 12 sheets ) as single shot development, I should need to take into account the more rapid exhaustion of the chemicals, right? So doing it that way would need longer development for smaller vol, single shot, but how do I calculate that? Over to you guys- I defer to greater knowledge. Mike