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  1. #21
    Photo Engineer's Avatar
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    DF;

    I have no idea what that means.

    I was a member of the CC at EK, and even gave classes there. I had an associate named Wightman as well, who made emulsions, but I never heard of this particular person or paper. I look forward to reading the paper.

    PE

  2. #22
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    Quote Originally Posted by Photo Engineer
    Donald, I agree with you, however, I notice a defninite difference in sharpness when I use a 4x5 holder vs a polaroid holder. I use my own coatings though and they are on 100# art paper, so that might make a difference. The exposures I've made on production paper were on MG IV RC, and were much sharper, but then the paper was thinner and had a baryta layer which improves sharpness. So, just consider my post a precautionary note that may or may not be important depending on paper thickness.

    And, the difficulties of coating on paper thinner than 100#, if FB are very great compared with thicker FB or any weight RC paper.

    PE
    Sounds like the real issues are hand coating and the materials available for that process vs. commercial paper, then. You're right, the Polaroid (500, 545, 545i) holders are designed for the thickness of the complete packet, and would be out the other direction if you used them with straight sheet film. FWIW, I wouldn't expect 100# paper stock to be much if any thicker than the RC I quoted above; I've got some 140# watercolor paper here that's well under .015".

    However -- flatness may be another issue, or you might be adding significant thickness of the coating. It'd be interesting to see what you get with a baryta coated paper...
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  3. #23
    Photo Engineer's Avatar
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    Donald;

    I'm working on a vacuum hold down plate for coating thin paper and film.

    It will have a heat/cool surface and will eliminate most of the problems coating on any material that can be held by the vacuum. Right now, hand coating is not a problem with the blades I use, at least on paper and film. It is just that it is more difficult on paper if the weight goes below 100#. This is due to the expansion of paper as it becomes wet.

    Imagine trying to coat on wet paper towels.

    In the case of very thin paper or film, unless you have a vacuum hold down, it is best to coat with a brush. And, if you do that, you cannot get production quality.

    PE

  4. #24

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    Use of Le Grey process

    I use the process of Le Grey since it delivers a fairly fast negative.
    I build a camera with a lens f8 to f11 and can make a good negative in 6 to 8 seconds. Compared to the process of Fox Talbot this is fast.

    The main problems are the sears for good paper, the search for raw chemicals and the required expertise to work with this process:
    * The paper is critical. You need a 80 to 100 gr paper, no watermark, fine textured, possible to work in wet conditions with the paper.
    * The raw chemicals can be found, I found some sourses but it took some time.
    * You need a good instrument to check weight and mixture. Some chemicals are expensive and you need for some chemicals 1 gr or less (if you prepare the solution in limited quantities).
    * Salting the paper can be done in advance, sensitising must be done the day you take the picture. Plan our work in advance. JJust taking a picture is not possible with this process.
    * After taking the picture and developping/fixing the material, the paper must be waxed. I use bee-wax (white) and an oven of 60-70 °C.
    * The final result is a thin waxed paper negative, breakable but with a beatiful density and tone. One can use salted paper as a printing medium.

    I

  5. #25
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    I sometimes shoot paper negatives. I use graded RC paper, when developed I strip the emulsion surface from the backer paper. I then stretch the emulsion on glass using oil, and sandwich with another glass. I mask the glass sandwich for 4x5 (my camera format) and enlarge. Enlarging times are slow, but I can get some decent prints.
    Rick Allen
    Argentum aevum

  6. #26
    holmburgers's Avatar
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    Quote Originally Posted by Karel Van den Fontey View Post
    I use the process of Le Grey since it delivers a fairly fast negative.
    I build a camera with a lens f8 to f11 and can make a good negative in 6 to 8 seconds. Compared to the process of Fox Talbot this is fast.

    The main problems are the sears for good paper, the search for raw chemicals and the required expertise to work with this process:
    * The paper is critical. You need a 80 to 100 gr paper, no watermark, fine textured, possible to work in wet conditions with the paper.
    * The raw chemicals can be found, I found some sourses but it took some time.
    * You need a good instrument to check weight and mixture. Some chemicals are expensive and you need for some chemicals 1 gr or less (if you prepare the solution in limited quantities).
    * Salting the paper can be done in advance, sensitising must be done the day you take the picture. Plan our work in advance. JJust taking a picture is not possible with this process.
    * After taking the picture and developping/fixing the material, the paper must be waxed. I use bee-wax (white) and an oven of 60-70 °C.
    * The final result is a thin waxed paper negative, breakable but with a beatiful density and tone. One can use salted paper as a printing medium.

    I
    Sounds like fascinating work you're doing. Would it be possible to share a picture of your waxed paper negative? I've always been curious to see how translucent it can become.

    Also, Rick, how do you strip the emulsion?
    If you are the big tree, we are the small axe

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