Thanks Denis, I see what ya mean by the volume of 35mm.... looks like I will need a few of the 35mm drums, for both high capacity runs (12 per drum) and low capacity, such as the 2 rolls of the 2523/21. I assume your point is, if your drums are too high capacity, you waste a lot of chemicals, cause the chemical fill is a function of drum size, not amount of film in the drum, correct?