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  1. #1
    jstraw's Avatar
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    Designing a tube system for large prints.

    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.
    1. A mechanism to make sure the wet paper doesn't roll up on itself in the tube, overlapping or collapsing on itself.
    2. Identifying a vessel that would be optimal as the development trough.


    Any ideas, comments or observations?
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  2. #2
    David A. Goldfarb's Avatar
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    If you hunt around you may be able to find one. Mine was made by Unicolor.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  3. #3
    jstraw's Avatar
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    Quote Originally Posted by David A. Goldfarb View Post
    If you hunt around you may be able to find one. Mine was made by Unicolor.
    David, what size will your do?

    The Uniroller that I have on the way has a couple of tubes but I don't think they look very big:

    http://cgi.ebay.com/ws/eBayISAPI.dll...7011&rd=1&rd=1
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  4. #4

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    I have a Cibachrome tube for 16x20, the interior is plain, if that helps. The diameter is about 6 inches. Jobo tubes have ridges that are supposed to catch the two edges of the paper and keep it sprung against the wall.

  5. #5

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    Good Evening, Jstraw,

    I think that David is correct; I seem to recall seeing an occasional very large drum (maybe for up to 24") on E-Bay. I can't recall any brand name(s).

    Years ago, I made my own from a piece of plastic tubing to which I glued one complete end cap and a second partial cap (about a 6" diameter hole in the middle for adding and dumping chemicals). It was either 8" or 10" in diameter and long enough to take 40" wide paper. I had no problem with the paper, Ilford RC, flopping loose during the processing. It adhered pretty well to the inside of the drum. I rotated manually on a bed to which I attached four upturned furniture casters. I had to work under safelight, of course, because one end of the tube was not light-tight. For the project I was working on, I just took the prints outside (it was spring, fortunately) and washed with a garden hose. The whole business was extremely makeshift--but it worked.

    Konical
    Last edited by Konical; 05-31-2007 at 10:00 PM. Click to view previous post history. Reason: typo

  6. #6

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    I do up to 20x24 in trays but I’ve been using PVC pipe for larger for about 20 years. I have an 8” x 38” tube that I do up to 24x36. I use end caps. One is a full cap and the other has a 2” hole in it. (I assume you are doing B+W, by the way, PVC pipe isn’t light proof.)

    There are a few tricks to learn, some specific to the larger sizes, but the general process is pretty easy. First, you need a sink. The end caps leak. It takes very little solution (I use a half gal. For the bigger prints but half that would work for 20x24. I simply put the print in the tube, lift the open end and pour in the developer, slip on the cap, lower it onto the rollers and let it run. The first rotation is a bit critical in that the print must “stick” to the tube. Once stuck, it will stay there. At the end of the cycle, raise the end, remove the cap and pour the dev. out and continue with the other liquids.

    The removable cap must have a hole or you can’t get it off. The liquid seeps in around the cap and a vacuum is formed when you pull on it. Also, the hole gives you a place to insert your fingers to pull on it.

    For the size you have in mind, I would make it at least 1” longer than 20”. The paper grows when wet. ( a 36” fiber base print will grow almost 2” in length when wet.)

    Getting it out is a bit tricky also. There are two ways that work for me. One is to peel the print away on one edge and roll it into a smaller roll and carefully lift it out. The other way works best with larger prints. Peel the corners loose and in a smooth motion pull it out and let it drop into the sink wit running water in it.

    More later if you’re interested.

    Jerome

  7. #7
    jstraw's Avatar
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    Quote Originally Posted by Konical View Post
    Good Evening, Jstraw,

    I think that David is correct; I seem to recall seeing an occasional very large drum (maybe for up to 24") on E-Bay. I can't recall any brand name(s).

    Years ago, I made my own from a piece of plastic tubing to which I glued one complete end cap and a second partial cap (about a 6" diameter hole in the middle for adding and dumping chemicals). It was either 8" or 10" in diameter and long enough to take 40" wide paper. I had no problem with the paper, Ilford RC, flopping loose during the processing. It adhered pretty well to the inside of the drum. I rotated manually on a bed to which I attached four upturned furniture casters. I had to work under safelight, of course, because one end of the tube was not light-tight. For the project I was working on, I just took the prints outside (it was spring, fortunately) and washed with a garden hose. The whole business was extremely makeshift--but it worked.

    Konical
    No doubt collapse would be less of a problem, as would washing, with RC paper.
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  8. #8
    donbga's Avatar
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    Quote Originally Posted by jstraw View Post
    No doubt collapse would be less of a problem, as would washing, with RC paper.
    Washing FB paper in large drums is problematic. RC works much better.
    Don Bryant

  9. #9

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    jstraw,

    I an currently making a tube system of 170cm wide.
    Therefore I use PVC pipes of 31,5cm diameter, cut in half over the length.

    I will post pictures when they are ready.

    We also have a roller system to roll the paper on for easy handling.

    Greetings,
    Geert

  10. #10
    David A. Goldfarb's Avatar
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    I have drums of various makes and sizes. The biggest is the 20x24" Unicolor.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

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