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  1. #1
    Mustafa Umut Sarac's Avatar
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    Autochrome / How to Remove Fixed Panchromatic Emulsion on Screen

    I want to use exposed and fixed Autochrome plates in my photography after removing the panchromatic emulsion which coated on to lacquer and dyed starch grain layer without damaging the second and third layer.

    George have unexposed Agfa Plates and he reported that if the plate put in to fixer without hardener , panchromatic layer peels off smoothly. I am in contact with him to obtain one or two plates but later I could buy Lumierre exposed ones and use them later also.

    How to question is above.

    Mustafa Umut Sarac
    Istanbul

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    MDR
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    Is the varnisch water soluble if not maybe the emulsion layer is and you can remove the emulsion by soaking the plate for a prolonged time in destilled water.

    Dominik

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    Mustafa Umut Sarac's Avatar
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    Hello Dominik,

    I dont think that varnish layer could be influenced with weak chemicals , its job is to protect the screen from developer , fixer and water. But may be finding a faster method could protect the glass corner , screen corner gap between varnish corner from the moisture. Are you confident that only distilled water peels off the emulsion ?

    Umut

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    Mustafa Umut Sarac's Avatar
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    Photo Engineer ,

    Your answer would be great .

    Thank you,

    Umut

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    MDR
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    Heated water works faster, or you could use a hair dryer set to hot (around 60°C - 70°C max ) the heat should destroy the gelatine emulsion. I mentioned distilled water because of the effects of water impurities water stains etc.... Formamide also known as methanamide is a gelatin solvent but i don't know what effects it will have on the varnish. This link might be interesting to you: http://albumen.conservation-us.org/l...ozlov1983.html

    Good luck

    Dominik

  6. #6
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    You could first develop the film to complete black and then use a copper-sulfate & hydrogen peroxide bleach. This will dissolve all the gelatin in contact with developed silver. This would be pretty damn easy methinks, as long as you have some kind of developer. In fact, if you used "Caffenol" or similar, you could probably get all of your materials at a grocery/pharmacy.

    edit: It just occurred to me that this would only work for unprocessed plates. If you're using a pre-existing color image, then the bleach would in fact get rid of the silver areas, but it would presumably leave the silver-free areas with gelatin and the thickness would vary then.

    Knowing what the varnish is made out of seems an important step. What about Shaz's thread, or Bertrand's book; do either say?
    Last edited by holmburgers; 08-01-2012 at 12:16 PM. Click to view previous post history.
    If you are the big tree, we are the small axe

  7. #7
    Mustafa Umut Sarac's Avatar
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    Chris ,

    Thank you very much. I can find hydrogen peroxide but I am not sure for copper sulfate. I have D76. Can only HP works as a bleach ? How much water and HP necessary in the mix , mixing heat and bleaching time and temperature are also necessary.

    Umut

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    holmburgers's Avatar
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    Copper sulfate is used to destroy tree roots, so check at a hardware store. But for some reason, I found some at a pharmacy. No, HP alone won't do anything that I'm aware of.

    Now remember, this is for an unexposed/unprocessed plate, but expose the hell out of it (i.e. take it outside and look at it for a long time in the bright sunshine... take your time). Then, develop it in D76 above 20° for any time greater than, let's say 10 minutes. This should definitely result in a black plate.

    Technically the copper-sulfate/hydrogen-peroxide mixture is a bleach-etch. Here's a thread about it... http://www.apug.org/forums/forum37/1...al-bleach.html

    If you are serious, we can look harder for a formula. I'm just a little lazy at the moment...
    If you are the big tree, we are the small axe

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    MDR
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    An overnight bath in a mix Methanol 1:1 Aceton seems to be the norm these days to strip the emulsion from the film.

    Dominik

  10. #10
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    Not to add too much confusion here, but if you are thinking about using old processed plates you may well have to remove a varnish layer to get to the emulsion. I believe it may have been common to coat the finished plate with a varnish to protect it. If the varnish layer is cracked (crazed) it may allow water to get to the emulsion and both layers lift off together. The Agfa instructions say to avoid an alcohol based coating and to use a Gum Dammar/Benzole varnish. This would indicate that the matrix is protected by a coating of shellac (one of the few finishes dissolved in alcohol). In fact I just made a trip to the basement and alcohol will weaken/remove the matrix protection. A thin film layer lifted off right away and the matrix layer could be removed by rubbing lightly with a brush. Once dry the color matrix that I didn't touch remained intact but very fragile when touched.

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