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  1. #11
    winger's Avatar
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    With liquid light, is it okay (or even preferred) to melt the whole bottle then pouring out what you need? Or can you melt just 'til you get enough for the amount of paper you're using? And if you open a bottle and use some, for how much longer will what's left be okay? A month or 2? months? years?

  2. #12
    Photo Engineer's Avatar
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    Quote Originally Posted by David A. Goldfarb
    Thanks for the update, PE. I'm still refining what I'm doing with albumen, but I picked up some photo grade gelatin from Artcraft, so I can try your silver chloride emulsion when there's a lull in various other projects I've got going.
    David, I have found that all gelatins are not equal when making emulsions. I have 3 different kinds at 3 Bloom Indexes. They are all different. Contact me if you have a problem.

    Things you might see include speed variations, contrast variations, aggregation and pepper grain (black dots on prints).

    PE

  3. #13
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    Quote Originally Posted by winger
    With liquid light, is it okay (or even preferred) to melt the whole bottle then pouring out what you need? Or can you melt just 'til you get enough for the amount of paper you're using? And if you open a bottle and use some, for how much longer will what's left be okay? A month or 2? months? years?
    See my post on finishing.

    When you heat an emulsion, you tend to restart the sulfur sensitization or restart the ripening process. This can be mitigated by the manufacturer by adding an inhibitor to the emuslion to prevent this. Also, the heat can start bacteria and fungi growth in the gelatin.

    I cannot predict how your liquid light would be affected, but felt it fair to advise you to try to limit heat to nothing more than 40 deg C (68 deg F) and try to limit it to as short a time and as infrequently as possible. This is the only sure way I know to keep an emulsion for a long time.

    There is nothing worse than the smell of a 'furry' emulsion covered with mold and starting to liqufy even in the cold. Unless perhaps it is an emulsion that has been fogged by repeated heat and cold cycles.

    I put mine into wide mouth containers and can then remove what I need by using a large spatula or my hands (with rubber gloves) without heating the whole container. I just cut off chunks and weigh them until I have what I need and only melt what I need.

    PE

  4. #14

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    Fish gelatin for phot emuslsions?

    Has any one tried the liquid fish gelatin sold at:

    http://www.norlandprod.com/fishgel/hipure.html

    to make phot emulsions? The company claims easy, non gelling liquidity of the stuff, solubility in water, and harding upon drying. Might be easiler than messing with the traditional gel type?

  5. #15
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    I know of no case in the photo industry where fish gelatin was used for anything. That does not mean it was not tried, merely that it was not widely known or worked with extensively.

    Cow bone gelatin and pig gelatin are the most common ones, with cow gelatin used far more often than pig gelatin.

    PE

  6. #16
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    ... I expect to publish a complete manual in the Fall for making both B&W papers and a medium speed film. Wish me luck, or as George Eastman said "pray for the emulsion"....
    Best of luck with the work. I saw the workshop blurb at CFAAHP and it looks great. I also look forward to the manual.

  7. #17
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    Quote Originally Posted by JG Motamedi
    Best of luck with the work. I saw the workshop blurb at CFAAHP and it looks great. I also look forward to the manual.
    Thanks for the plug.

    I hope to see you there.

    If you prefer 'big sky' country, you might consider the workshop in Montana in June.

    PE

  8. #18
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    Quote Originally Posted by Photo Engineer
    limit heat to nothing more than 40 deg C (68 deg F)
    PE, just looking through threads about emulsions and noticed this typo...is it supposed to be limited to 40 C (104 F) or 20 C (68 F)? Thanks for your help. Not sure if I'll get to my related project soon, but am interested in trying some of this out...

  9. #19
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    Quote Originally Posted by Troy Hamon
    PE, just looking through threads about emulsions and noticed this typo...is it supposed to be limited to 40 C (104 F) or 20 C (68 F)? Thanks for your help. Not sure if I'll get to my related project soon, but am interested in trying some of this out...
    Troy, thats a typo. It should be 40 deg C (104 F). Gelatin will set up at 20 deg C (68 deg F). Above 40 deg C, the finishing and ripening can speed up and ruin the emulsion. I am distinguishing between these two but some tend to lump them together.

    Thanks for the catch. Sorry.

    PE

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