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  1. #11
    Andrew O'Neill's Avatar
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    I've had much better luck applying the fumed silica wet rather than dry. I even went so far as to buy a cheap blender to mix it. But otherwise, my experience with it is on a par with what Mr. Klain says - it produces a notable boost to Dmax and overall contrast increase. And applying it wet doesn't add THAT much time to the coating process. I find it dries to a coatable surface within minutes.
    What's your mixing ratio, if you don't mind my asking? Thanks.

  2. #12
    dpurdy's Avatar
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    Quote Originally Posted by TheFlyingCamera View Post
    I've had much better luck applying the fumed silica wet rather than dry. I even went so far as to buy a cheap blender to mix it. But otherwise, my experience with it is on a par with what Mr. Klain says - it produces a notable boost to Dmax and overall contrast increase. And applying it wet doesn't add THAT much time to the coating process. I find it dries to a coatable surface within minutes.
    I on the other hand find it much easier to coat dry. It is so easy to do that I now always use the silica even with my test strips. It takes so very little powder to brush on that the most common problem is from trying to put on too much. My first try wet produced streaks so that was the last I tried it. The dry method is too easy.
    Dennis

  3. #13

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    Quote Originally Posted by TheFlyingCamera View Post
    I've had much better luck applying the fumed silica wet rather than dry. I even went so far as to buy a cheap blender to mix it. But otherwise, my experience with it is on a par with what Mr. Klain says - it produces a notable boost to Dmax and overall contrast increase. And applying it wet doesn't add THAT much time to the coating process. I find it dries to a coatable surface within minutes.
    How do you mix it? Quantities? Suggestions? I am thinking one could do up several sheets for future coating.
    Thanks for your observations.
    "There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).

    Regards
    Bill

  4. #14
    TheFlyingCamera's Avatar
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    I mix it with distilled water to the B&S recommendations, then roll it on with a foam roller. One of the other reasons I use it wet is that I'm asthmatic and prone to respiratory problems. I don't need to be inhaling any more fine particulates than I have to.

  5. #15
    Klainmeister's Avatar
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    Heh, funny. I tried it a few times wet and always ended up with streaks and stuck with dry after that. I don't even know a good base to being with.

    Regarding archival quality: fumed silica is pure silica, which in effect, should have no, to little effect on the paper itself, nor the metals in the print. Granted, it's so new who really knows? We did do a trusty NM test where we tape a print to a door facing the southern sky, which here in NM is always sunny and at 7000', quite harsh. No fading or issues after a handful of days, which usually will destroy some of the older RC paper emulsions, etc. Not scientific, but confidence inspiring.
    K.S. Klain

  6. #16
    TheFlyingCamera's Avatar
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    As for a base, my preferred paper is Bergger COT320, and my #2 choice is Rives BFK.

  7. #17

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    In my search for better papers for Pd/Pt printing I also tried fumed alumia dry or wet applied. It gave better contrast and Dmax with several papers but bad mids and highlights (like too much restrainer). The fumed alumina suspended quite easily in Ethanol and that suspension has to be diluted with a lot of water (otherwise it soaks completely through the paper).
    I am not so sure that more sensitizer increases Dmax. I investigated some prints under a stereo microscope and found often only the very top fibers get coated but in the mids it is apparent that some fibers get no or only very little Metal deposited. This explains the mottled mid tones. Papers like Buxton or Herschel have not that effect. I also investigated coated but not developed paper and found that different fibers within the paper surface have absorbed different amount of sensitizer. I have to make more of these studies but I think the goal is to get all the fibers absorb the sensitizer. Simply adding more will likely only act as a filter during exposure without contributing to image density.
    Last edited by jakobb; 04-09-2013 at 05:25 PM. Click to view previous post history.

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