a vacuum question

Discussion in 'Alternative Processes' started by marko_trebusak, Oct 13, 2005.

  1. marko_trebusak

    marko_trebusak Member

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    Uf, my Zia process using Canson Opalux paper is almost ready. I got some nice looking 5x4 photos, and now I would like to move on. The trouble is, that this paper curl a lot when coating, but on the other hand it's very hard when dry, so it's a challenge to get good contact with negative. I solved this by pre starching the paper, like watercolour painters would. So here come my question:

    I would like to use vacuum for the best possible sharpness. I have paper taped down on sheet of glass. Now, if I put a thin sheet of Mylar foil to cover the paper, made some holes in glass for vacuum hoses, and evacuate air between glass and mylar would that do the trick? My fear is, that vacuum will just suck foil down around holes, leaving air under the rest of the sheet.

    Thank you
    Marko
     
  2. nze

    nze Member

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    Hello

    It won't work. you will a plan of a good vacuum base on the b&s web page( just search in the technical pages)

    But if you use a vacuum with zia it is recommended to put one mylar sheet also on the back of the paper to avoid it to dry

    best
     
  3. marko_trebusak

    marko_trebusak Member

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    Christian, why do you think that it'll not work? I don't see problems with sealing, since Mylar is thin and flexible enough. My only concern is local vacuum with air left in other parts. I saw vacuum frame on B&S site, and I actually made it (I only need glass cover to complete it). The trouble with my process is glass support on which my paper is taped down. I would need to made another frame, because on existing one washer is to thin for this new application and the frame is slightly too small.

    Marko
     
  4. nze

    nze Member

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    Marko

    In fact it will work with paper like crane's kid finish or cover. But I already try such system with Arches platine and on big sheet I got flatness problem due to the humidity in the paper.The pressure of the mylar ( even if mine use another polyethylene) wasn't stong enough to keep some paper flat.
     
  5. marko_trebusak

    marko_trebusak Member

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    Thank you Christian! As I mentioned in my original post, I'll be working with pre stretched paper, because it's impossible to work with Opalux the other way. It's very hard to coat, because it wrinkle rather a lot when it's wet (it's a tracing-like paper) so a paper flatness will not be an issue.

    Marko