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  1. #11
    Photo Engineer's Avatar
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    Nick, only one side is sized. It is the smooth side.

    PE

  2. #12
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    FWIW, you may experience some significant shrinkage issues if you use COT320 for multiple printing (e.g. multiple gum or gum over platinum). IME, it shrinks non-proportionately perpendicular to the grain of the paper. To make it into a good gum over paper, I would run it through at least one hot water pre-shrink before printing on it. And this step will probably remove some of the manufacturer's sizing. If you are just doing a single coat gum or a platinum or palladium print, then the dimensional stability is not an issue.

    Also, it was my understanding that COT320 was sized with gum arabic, not gelatin. I think I read this in the Dick Arentz book.

  3. #13
    nick mulder's Avatar
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    Quote Originally Posted by Photo Engineer
    Nick, only one side is sized. It is the smooth side.

    PE
    well that explains a few things (; - I'm getting much flatter yet blacker blacks on the rough side and it does need a few extra drops to get the full coating

    So I'm assuming the smooth side is the one meant to be printed ? I prefer the other... there are so many variables I could be doing two things incorrectly that inadvertantly make it better somewhat ? but not the best it could be ...

    i started this thread WRT gum but I am talking about pt/pd here ...

  4. #14
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    Nick, I'm sorry I cannot help you. I do only silver halide in gelatin.

    I know that the smooth side (calendered) is the side for coating, and the reverse side (wire side in the trade) is not. That is normal papers. This is most differentiated (AFAIK) in hot press papers. Cold press papers are harder to differentiate between the face and wire side.

    The face side is usually subbed with a size coat and in photo grade papers has Baryta in gelatin.

    PE

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