What I have in mind is a pvc tube, 8" diameter and slightly longer than 20" in length. This would accommodate a sheet of 20x24 paper since the inner circumference of an 8" tube will be just under 25". If it's too tight, I'll go to a 24" length and roll the paper the other way. The tube would either use one or a series of well fitted trough shaped pans (yet to be identified with a couple of inches of chemistry in the bottom. Prior to washing the ends would be uncapped and the tube would be rolled with gloved hands in the trough(s). For washing, I have an idea about using a pair of end caps, with a round hole cut in the center of the caps. A water hose would feed a low-flow in one end and the water would drain out the opposite end. The donut caps would ensure a certain depth of water in the tube. The tube would be turned during washing by a Uniroller. Here are the design challenges I've identified. A mechanism to make sure the wet paper doesn't roll up on itself in the tube, overlapping or collapsing on itself. Identifying a vessel that would be optimal as the development trough. Any ideas, comments or observations?