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  1. #11
    dwross's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    That is grade 2. It is the ISO washed version mentioned and varies only by using PA gelatin (from the Formulary). You saw my methods in the workshop and I show a picture of this in the DVD thread.

    PE
    I don't think you got to ISO washing in our workshop, or if you did, I missed it. PA gelatin wasn't available at the time, so it might have seemed a bit theoretical to my poor, saturated brain.

    I have all the ingredients for your recipe on hand except the PA gel and I think I'll try to do without it and ISO washing. Speed matters not much so much to me. I prioritize for clean and clear. Also, expense and ease of making. I remember thinking during your workshop when you were rattling off the whole list of tools and materials that weren't available any more (or soon would be gone) that my research would concentrate on materials used by the gourmet/ fast food industry. Now, there's something that will never go out of fashion. If it were part of making fine chocolate, I could keep that going all by myself. I figure if you add gummy bears, I've got gelatin and dyes covered. Now, I just need to identify how to keep silver nitrate in the public sphere.

    I'll let you know how it goes. I'm curious to see how much difference gelatin choice makes.

  2. #12
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    Quote Originally Posted by dwross View Post
    I don't think you got to ISO washing in our workshop, or if you did, I missed it. PA gelatin wasn't available at the time, so it might have seemed a bit theoretical to my poor, saturated brain.

    I have all the ingredients for your recipe on hand except the PA gel and I think I'll try to do without it and ISO washing. Speed matters not much so much to me. I prioritize for clean and clear. Also, expense and ease of making. I remember thinking during your workshop when you were rattling off the whole list of tools and materials that weren't available any more (or soon would be gone) that my research would concentrate on materials used by the gourmet/ fast food industry. Now, there's something that will never go out of fashion. If it were part of making fine chocolate, I could keep that going all by myself. I figure if you add gummy bears, I've got gelatin and dyes covered. Now, I just need to identify how to keep silver nitrate in the public sphere.

    I'll let you know how it goes. I'm curious to see how much difference gelatin choice makes.

    Denise;

    We did do the ISO wash for the camera speed film. You all had your (my) red flashlights in my beaker to watch the pH meter. I hope you remember that. In fact, both of these formulas are in the handouts that I gave you. This formula is directly from one of those pages. The ISO wash is on the next page.

    The ISO wash does several things. Since there is less bromide, the finish with hypo is faster, and you can coat the emulsion on film or plates without the formation of crystals. Those are the big differences.

    PE

  3. #13
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    The Formulary has Kodak Phthalated Gelatin now, but I believe that the price of this gelatin is about 2 - 3X higher than the regular Photo Grade that they sell. At the time of the workshop, the drums had not arrived IIRC, and I had to bring my own sample to the class. I was unable to find it on their web site, but I have ordered it from them and have a bottle of it here now.

    The formula above, when used with an ISO wash uses more Phthalated Gelatin than usually desired, but the reason is to make the procedure fullproof for a non-chemist. It does not materially affect the speed of the emulsion as far as I can determine as long as things are done properly.

    Using an unwashed emulsion such as this works just fine on most all papers, but as I noted earlier here, it will cause crystals to form if coated on film or glass. Therefore the ISO 40 ortho emulsion, shown in the DVD, is washed.

    PE

  4. #14

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    I bought 1 lb of the PA gel from the Formulary in February. I think it was about $60.

    I'm going to try the film speed formula I've been working on with the regular gelatin one more time (3rd try is the charm, right) and then I think I'll switch to the PA gel for it's washing characteristics. And I finally have a pH meter and electrode - all lab grade equipment from ebay and for under $100.

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