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  1. #31
    Photo Engineer's Avatar
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    Dont forget that the Formulary has a number of unlisted chemicals for emulsion making such as PMT (Phenyl Mercapto Tetrazole) and TAI (Tetra Aza Indene). These are excellent antifoggants and stbilzers that are used in a number of emulsions. With TAI (supplied as a powder or in solution) you can make your emulsion keep for a long time with no change in properties.

    PE

  2. #32

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    Quote Originally Posted by Photo Engineer View Post
    With TAI (supplied as a powder or in solution) you can make your emulsion keep for a long time with no change in properties.
    Liquid emulsion or the coated film/paper?

  3. #33
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    Actually, both!

    PE

  4. #34

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    I've got questions about a couple items that need to be purchased.

    I've got a 1/4" 11x14" piece of glass that I plan to use for contact prints in my darkroom. I haven't used it yet but I thought I could either lay paper, negs and glass on the baseboard, or get some thin foam to lay on top of the baseboard first. Will this work for the project? Or do I need to purchase the contact frame that was suggested?

    Also we need a "reliable" scale that measures as low as 0.01 g. First could I get some recommendations as to which ones are "reliable?" Also what's the top end the scale should be able to measure? Some are 20g, some 500g, etc.

    Would either of these fit the bill?

    http://www.amazon.com/US-Balance-Dig.../dp/B00123AVTO
    http://www.sciencecompany.com/Parts-...1g-P16791.aspx

    Thanks,
    --
    Kenton Brede
    http://kentonbrede.com/

  5. #35

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    Quote Originally Posted by Photo Engineer View Post
    Actually, both!

    PE
    Cool! I'll get some. Which one is better? Or should I get/use both?

  6. #36
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    Kenton,

    The one from Amazon looks like a great scale.

    The two scales are a perfect example of the trade-off between upper and lower end precision -- at least for any scales I can afford. The rule of thumb I was taught is that you want a decimal point of measurement beyond what you expect to weigh. i.e.: If a recipe calls for 5.5 g of doodlebugs you'll want a scale that measures to 5.50 grams. I have two scales that have almost the same ranges as the two you have here. I almost never pull out the 0.1 scale. I just don't have the room for two scales out and the work-around isn't a big deal. If I need 150 ml (grams) of water, I weigh out the water in a couple of divisions.

    Important, though: You'll want a calibration weight, or even better, a set of them. The instructions for calibrating the scale will be included with your model. It's very easy, but very important.

    Re: contact printing under glass. It can be done. It will be fine in the beginning as you're learning and deciding if all this is something you really love doing. But, in the long run, especially with handcoated paper that isn't dead flat when it dries, the tight contact afforded by a good spring-back frame can't be beat.

    btw: excellent questions!
    www.thelightfarm.com
    Dedicated to Handmade Silver Gelatin Paper, Film, and Dry Plates.

  7. #37
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    Quote Originally Posted by anikin View Post
    Cool! I'll get some. Which one is better? Or should I get/use both?
    They each have slightly different uses so I would get both.

    If you are in Rochester for any reason, I can give you a tiny starter amount for your lab. Otherwise, the Formulary is your best bet. Sherry knows where the bottles are kept.

    PE

  8. #38
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    For contact printing, I use a metal framed heavy glass printer that I bought locally at a photo store. It is so heavy that no wrinkled or curled paper has defeated it!

    Denise is right thou;gh. You want something heavy to insure flatness.

    PE

  9. #39
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    When looking at the specs for weigh scales, note that accuracy and resolution are not the same thing!
    - Ian

  10. #40
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    Hi Ian,

    Nice to see you here again. I hope this means you've cleared your work load enough to get back to making emulsions!
    d

    p.s. In case anyone has missed it, emulsion101 is more than Ian's website, it is a silver gelatin emulsion forum he established.
    www.thelightfarm.com
    Dedicated to Handmade Silver Gelatin Paper, Film, and Dry Plates.

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