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  1. #11
    Andrew O'Neill's Avatar
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    From the short time that I have been playing around with the kallitype process, I don't bother with double-coating. I tried it but did not see an increase in Dmax. I did however, have a slight increase in speed. I use Rising Stonehenge sized with gelatin. I brush on the single coat, let sit for one minute, and then dry with hair dryer on cool setting.
    Double coating worked better on the same paper without the gelatin sizing. I get a much cooler colour on the unsized paper and warmer on the sized.

  2. #12

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    Van Dyke can have an excellent Dmax with single coats, I don't know too many folks who double coat for vdb. But it's really going to depend on many factors.

    The type of paper is the most critical variable, on some papers two coats would be essential, but most well-sized papers should do fine with a single coat. The trick is to saturate the surface layer, after it's richly coated then a second coating won't yield any better results. A second coating could even lower dmax (in some situations) by washing more stuff into the middle of the paper where it won't be seen or exposed. Also, double coating runs the risk of scuffing up the paper surface on softer papers.

    Humidity and coating technique are also important. Brushes work better on hard sized papers, coating rods can be more effective on softer papers.

    Hey Loris, are you using a coating rod on the Cot-320? That paper has been really hard sized the last few batches and I find that coating rods don't make the stuff soak in quite as well. It might happen with soft, light brushing too. The effect is a flaky white look in the print, it kind of matches the paper texture. Try throwing in a drop of tween 20 or photo-flo to break down the sizing, or get one of those cheap disposable foam brushes. The foam brushes scrub the surface real nice and make the coating soak in better. The paper is super tough, so with cot-320 abrasion isn't an issue. My guess is your first coat softens the sizing up, then the second coat fills in the gaps. My brother Dana's trick of putting down a coating of distilled water first, then coating the emulsion later (let the water dry completely) would also work in this case. Good luck.
    Kevin Sullivan
    Bostick & Sullivan, Inc
    www.bostick-sullivan.com

  3. #13
    davido's Avatar
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    Brushes work better on hard sized papers, coating rods can be more effective on softer papers
    this is interesting but how do you tell if a paper is hard or soft sized? Is Stonehenge paper hard or soft sized? Or Arches Platine?
    I would say that humidity is hugely important. I'm finding that it's more important than the issue of double coating.

    david

  4. #14

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    Hi Kevin, I have used both methods depending on image size. I don't have a collection of rods; I use the rod if any of the two dimensions of my image is 10", I use a - correspondingly sized - brush for other image sizes... and don't worry; I'm pretty well accomplished in coating paper

    I suspect the specific batch of FAC I use could be a reason of this phenomenon; I use the same batch (2 x 500g) that I purchased from you back in 2003. I never managed to mix Vandyke and/or Argyrotype without precipitation with your FAC. When I asked about this to Mike Ware, he was surprised; eventually his FAC (from Sigma-Aldrich) doesn't cause any precipitation. Since not every FAC batches are created equal, maybe that's the cause of the difference between our observations / procedures?!

    Anyway, I don't do Vandykes anymore -> the inconsistency / mixed reports about FAC caused me to put away the processes which need it. Nowadays, I prefer FAO or dichromates as sensitizer

    Quote Originally Posted by Kevin Sullivan View Post
    ...Hey Loris, are you using a coating rod on the Cot-320? That paper has been really hard sized the last few batches and I find that coating rods don't make the stuff soak in quite as well. It might happen with soft, light brushing too. The effect is a flaky white look in the print, it kind of matches the paper texture. Try throwing in a drop of tween 20 or photo-flo to break down the sizing, or get one of those cheap disposable foam brushes. The foam brushes scrub the surface real nice and make the coating soak in better. The paper is super tough, so with cot-320 abrasion isn't an issue. My guess is your first coat softens the sizing up, then the second coat fills in the gaps. My brother Dana's trick of putting down a coating of distilled water first, then coating the emulsion later (let the water dry completely) would also work in this case. Good luck...

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