Thats right, 55ml is all it takes to develop prints in whatever combination will fit inside without overlapping. One 10 x 8 or four 6 x 4 prints for example. I use mine to develop both prints and 5 x 4 negatives, 4 at a time. If you intend using it for negatives it will require an easy modification to stop them sticking. It was originally supplied with three coloured chemical measuring beakers. I also use 150ml of developer for four 5 x 4 negatives. Im fairly sure 55ml would be ok for this task, but have never had the time to try, so I ere on the side of safety. You must use the red spacer pegs if you are using it for smaller than 10 x 8 prints or negatives. If you have the electric motor base it will be much easier, and more consistent. For other reading this, we are discussing a daylight processing tank, load it in a changing bag, snap on the lid, and its light-tight, just right for LF negs.