Bergger COT-320, "good" side and coating recommendations Pt/Pd

Discussion in 'Black and White' started by beepy, Nov 3, 2005.

  1. I have some Bergger COT 320 I've started to play with. Please confirm that the "good" side to
    coat is the extremely smooth almost toothless side. The other side has much more tooth.
    I am rod coating with Pd. My humidity is around 60%. I got a smooth coat on the paper, but
    seem to have put too much emulsion down (black runoff on development). I'm not using
    Tween or anything?
    Any thoughts? or insights?
  2. You are correct, the smooth side is sized with gelatin. I don't know if there is hardener in it.

    I have two batches of COT320 and they behave just a little bit differently when coating. This is inevitable, I understand, due to variations in the cotton rag used for making this high quality paper.

    Ron Mowrey
  3. Thanks! Could you describe your coating method? Any insights?
  4. I coat silver halide emulsions with my own design of coating blades.

    This may or may not help you.

    Ron Mowrey
  5. maybe you are putting to much emulsion down.

    i perosnall coat with rod and brush and am using about 23 drops for a 6x8 (as a base) then double as i increase the paper side.

  6. Yes, there definitely is an "Up" and a "Down" side to Bergger C0T320. The smoother side is the one you want to coat on. I would recommend switching from the rod to a Richeson 9010 brush (aka "magic brush"). You will find you get much better results with your coating than you do now - more even, and less raising of the paper nap. Get the brush wet in distilled water, and flick it partially dry before coating the paper. That way the brush won't absorb too much of your pt/pd solution.

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