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  1. #1

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    Higher contrast\less fog

    In using my latest batch of emulsion, I decided to just keep it in the tall stainless steel developing tank for melting and refrigerating. After a couple of cooling and melting cycles of the whole thing I noticed the image is clearer in the shadows and has more contrast. There must be some additional ripening or digesting going on with reheating several times.

  2. #2
    Bill Burk's Avatar
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    While I wouldn't mind being involved in the emulsion making community, I'm nowhere near able to contribute to your thread - other than to say ... keep up the good work.

  3. #3
    Hexavalent's Avatar
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    Repeated melting/cooling of an emulsion is going to change its sensitivity, contrast and fog, as well as changing (damaging) the gelation properties.

    Is this an unwashed or washed emulsion?
    - Ian

  4. #4
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    That's interesting. I have to agree with Ian that it's not something I would recommend but you seem to have come across something useful.

    FWIW, I do keep my emulsion in the digestion kettle (a heavy bottomed drink glass of some sort from dollar store) which is stored in a stainless "emulsion can" (cheapo kitchen canisters) in the refrigerator. FWIW, when I decide to make a few rolls out of a batch, I dig out the amount I need with a tablespoon and melt in a second container in a little potpourri crock pot I found in my mom's garage. You can pick up some cheap stainless spoons (you need metal ones - plastic will break) at your local dollar store so you don't need to steal from the kitchen. The remaining portion goes right back in the fridge.

    Never underestimate the value of the local Dollar Store for finding emulsion making gear.

    -- Jason
    All this has happened before, and all this will happen again.

  5. #5

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    I normaly do put the emulsion in a smaller container and take only what I need, but as an experiment I remelted the same emulsion everal times to see what it will do. It is a washed emulsion.

  6. #6
    Hexavalent's Avatar
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    Each time you re-melt the emulsion, you are likely ripening it a little more. In addition, unless the emulsion is continuously stirred, there is probably some settling of the grains - the top of the beaker has different sized grains than the bottom.
    - Ian

  7. #7
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    I don’t know if this helps, but with regards to liquid emulsion, I decant into a dozen or more 35mm cassette containers and keep them inside a dark plastic paper box print bag, in a tray. In this way I can put one or more in hot water before use, without having heat up the whole batch.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  8. #8
    dwross's Avatar
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    An open question to anyone: Why do you only coat a plate or a few at a time? There must be a good reason, but I'm stumped, except maybe a space issue (??) I'm limited in my darkroom space, so I can only coat a dozen 4x5's at a time, but it's really nice to have that many.
    www.thelightfarm.com
    Dedicated to Handmade Silver Gelatin Paper, Film, and Dry Plates.

  9. #9

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    I do'nt coat too many plates at once because if they sit for a long time (month or two) they start to loose density, so I only make what I think I might need for the time beeing.

  10. #10
    Hexavalent's Avatar
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    Space and time constraints usually limit me to coating 12-20 plates at a sitting. For this reason, I only wash the amount of stock emulsion that can be used within 24 hrs, melt what I can coat at one sitting, and keep plates refrigerated if I'm not going to be shooting them within a day or two. I'm in the habit of adding an anti-foggant (TAI) to every batch to lessen any "after ripening" during storage.

    Comes the happy day when I can enlarge my lab area, and not have the distraction "regular work", I'll be able to scale-up the process.
    - Ian

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