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  1. #11

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    Jun 2007
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    The Ortho film was coated on both Estar and paper support. The coatings on film were low in quality due mainly to severe reticulation. This was most likely because we processed after only about 20 hours keeping and the hardener was not fully reacted. In any event, the film coatings were a good ISO 80 speed and the paper negatives were at least 200 speed. We experienced difficulties coating on the film support but not on the paper support. The emulsion appeared to be too low in viscosity. Addition of some gelatin boosted coating quality.


    Hi Ron - this is my first posting to the APUG group. I've been lurking in this thread for some time now. Congratulations on your success with the emulsion making classes at PF.

    As you know, I made test coatings on 30x40" sheet of my Dye Transfer matrix film in my lab. I used my large travelling slot coater to coat 36 x 50" pieces of Melenex film with a subbing layer on it. Generally, I got very good coatings, but occasionally I would get reticulation during emulsion drying. This was a totally unhardened emulsion, so it was probably more prone to this than your emulsions with have a hardener added. Also, the coatings were very thick (> 25 um dry).

    I found that the reticulation was worse in the Winter (New Hampshire = very dry in winter). During the summer, the humidity can be very high, and it slows down the drying action. During the Winter, with my HEPA filter running continuously, I could get reticulation starting on the leading edge of the air flow. Generally is appears in a limited area on the leading edge. I found that I could minimize the problem by putting the HEPA filter motor on an interval timer, where I would run it for 30 seconds every 5 minutes initially, ramping up to full on continuous during the final stages of drying. I made no attempt to regulate temperature or humidity (other than the fact the humidity went up in the cabinent when the fan was off).

    Regards - Jim Browning (www.dyetransfer.org)

  2. #12
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    Jim;

    Welcome to APUG.

    Thanks for the comments. It was very cold and dry at the PF. In fact, it snowed in the moutains several times while we were there, but it was too cloudy at those 9000 ft heights to see.

    We could see the reticulation in the wet emulsion after processing, and watch it as it dried slowly. The glass plates took overnight to dry as they were the last ones to be run through. None of them were any good due to reticulation problems.

    We got no reticulation in NYC or at home here, but have gotten it both years at the Formulary workshop. I used the same materials, only the water used for processing, and the climate were different. It only shows up on film coatings or plates. I had attributed it to the short drying time after coating the film or plate, but if that were so, the NYC materials should have had some problems, but they did not. So, I'm reconsidering that guess.

    PE

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