Anchell & Troop's position is a universal 250 ml per 80 square inches of film. Based on that and 1:9 dilution, 25 ml of Ilfosol-S concentrate should be adequate for a 135-36 or 120 roll. I'm using 375 ml when processing 120 TMX at 1:14 and have seen no evidence of insufficient capacity.(posted 8354 days ago)