Polyglot - do you have a means of processing lengths of paper on the roll (not necessarily the whole roll at once) or do you expect the built device to output individual cut sheets, which needs a much more complicated mechanism. If you want individual sheets to size, it would be easier to cut them to length and store them in batches, perhaps using a stepper motor or digital counter and DC motor. Incorporating a mask and a guillotine means winding a bit forward after exposure to clear the mask, then cutting, then winding back to position the paper back beneath the mask, otherwise each print would have a margin of wasted white paper.
In a previous career I designed paper handling devices. The trickiest bit was interfacing every possible enlarger to the rolleasel. I ended up using a photocell and plastic fibre optic to link the lamphouse to the control. This sensed the end of the exposure and advanced the paper.
I was considering integrating a guillotine or rolling cutter with the papersafe, but am concerned that (with a rolling cutter anyway) dragging the paper under the clamp-bar could scratch the emulsion.
I have two Rota-Trim units in my darkroom for cutting roll paper. One is set-up for colour paper with a quite impressive cardboard guide system using genuine duct tape, this was for 40cm wide roll paper manufactured in Australia by Kodak. I also acquired some Fuji roll paper, it was 30cm in one box and 8" in another box. The metric paper was Japanese and Australian stock, the imperial paper was presumably for the USA market.
The other unit was set-up for B&W 50cm (I think) roll paper from Agfa Australia, this was RC and a great success. I had a series of cuts set-up allowing me to make three sizes of cut sheet paper.
I believe you will find paper emulsion is quite tough, really tough. One can of course damage it, but my experience is that it takes a hiding.
One just lifts the plastic guide on the Rota-Trim unit, slides the paper in to a pre-arranged stop, places the plastic guide down, then runs the trimming wheel back and forth. Got so good, I could do it with my eyes closed.
I must confess though, I haven't used either for some years as my stock of roll paper eventually finished and I obtained some mountainous supplies of paper from closing shops. One haul was 30x24" paper in 50 sheet boxes by 18 boxes, that was the RA4 colour, you don't wish to know how many B&W boxes I obtained.
Mick.
See this as well: (there was a url link here which no longer exists)
That looks pretty good, and is approximately what I was imagining. I take it you do the cutting with the box open and then close it for storage?
Having said all that, I have to ask what your motivation is for buying rolls of paper? I did a quick cost analysis based on B&H's current prices for Ilford MG Classic on a 42"x 98' roll vs a box of 250-8"x10". An 8"x10" cut from the roll costs 2 cents more and you have to do all the work! Never mind dealing with the curl.
I probably shouldn't even input to this thread since I've never used roll paper of any kind, but I'm going to risk it. I've always assumed, without basis, that rolls are intended for use by high-volume commercial processors in which the paper would be moved directly from the roll to a vacuum easel (to keep the paper FLAT during exposure), then into the developer where it would soften and start to relieve the curl. Otherwise, I assumed it'd be like trying to wrestle with an alligator. This process would also be a big advantage as the end of the roll is approached and the curl becomes severe. I could never imagine the use of rolls for myself, since my output rate could never justify the hassle or compete with a commercial rate. Just my 2 cents.
Guess I just need to wait for a good deal on a nice rotatrim.
For anyone who has used the Ilford rolls, what is the inner diameter of the core? Can you run a rod all the way through it or does it need to be supported by two short pegs?
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