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  1. #1
    Mustafa Umut Sarac's Avatar
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    Panchromatizing Spray or Liquid Emulsion for Autochrome

    I read many posts about Autochrome and developed my idea.

    1- Buy a sheet of melinex.
    2- Print a screen with original Autochrome dyes or Cheaper Starter equivalents with CMYK.
    3- Tape printed side of melinex to the anti halo sprayed glass.
    4 - Spray or coat the other side with emulsion.
    5 - Take picture
    6 - Develop
    7- Remove the tapes and you have a autochrome.

    I discussed this idea with Chris and he said that I needed to panchromatize the emulsion.

    If I am not wrong , there were tube spray emulsions at the market.
    How can I panchromatize sprayed emulsion before hardens ? Or can it be processed after hardening ?
    If it is not possible , I would like to learn about panchromatizing liquid emulsions. What is the recipe ?

    Thank you ,

    Mustafa Umut Sarac

    Istanbul

  2. #2
    Photo Engineer's Avatar
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    The problem is multifold.

    1. You need to determine if the original emulsion is sensitive to other than blue.
    2. If 1 = yes, then sensitize to the region(s) left out of #1. Hope that the new dye(s) do not remove existing dyes if any.
    3. If 1 = no, then you need to get the proper pan dye to add and just add it with no worry.
    4. Make sure you work in total darkness or IR.
    5. Before you do anything, find a source for the dye.

    Now, how to do 2 or 3. Dissolve the dye in an appropriate solvent for the dye. This will usually be at the rate of 100 mg - 1 gram / 100 grams of solution. This is then normally added at about 50 - 100 mg of dye / mole of Silver to the melted emulsion and held for 15 minutes with stirring before coating. All should be normal from this point on.

    If the coating is already made, you will have to work entirely by trial and error to bathe the emulsion in dye solution to give the right sensitization. You should wash briefly after the soak in dye solution. This method is the least desired.

    During this all, remember that the emulsion starts out with zero added sensitivity, increases speed in the desired region of the spectrum as dye level is increased, and then as you go up from there, both peak and blue sensitivity will decrease and development rate will decrease. Dyes are desensitizers and retarding agents at high levels.

    PE

  3. #3
    Mustafa Umut Sarac's Avatar
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    Where can I buy pan dye from ? Is it only one or for every different spectrum ?
    What are the spray or liquid emulsion brands which can be converted to panchromatic with one dye without worrying about the premixed dyes ?
    Is it possible to panchromatize sprayed or coated dry emulsion ?

    Thank you Ron ,

    Umut

  4. #4
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    In Europe, IDK what companies sell dyes. You can make an emulsion panchromatic either by using one broad dye or two narrow dyes. The latter is more difficult.

    PE

  5. #5
    Mustafa Umut Sarac's Avatar
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    Ron ,

    Where do they sell these pan dyes at US ? I am still thinking to add to Liquid Light Emulsion and spray to back of the screen.

    Umut

  6. #6
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    Try H. W. Sands Corp. in Florida. In Europe try Honeywell.

    They might help.

    PE

  7. #7
    Mustafa Umut Sarac's Avatar
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    Thanks Ron ,

    I looked their website and there is sensitizers selection menu with wavelenght input function.
    I sent every detail about my autochrome knowledge including sensitometry curves and asked Liquid Light to suggest me one of their emulsions and sensitizer selection.

    I hope they help me. Otherwise , I will request curves and do whatever could be done on APUG .

    Umut

  8. #8
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    from this book... http://books.google.com/books?id=fS9...ophyll&f=false

    In 1879 Mr. F.E. Ives suggested the use of chlorophyll of blue myrtle or periwinkle leaves for making collodio-bromide plates colour-sensitive. The chlorophyll is prepared by steeping the leaves, when cut into small pieces, in pure alcohol and heating for a few minutes. The solution of chlorophyll is in its best state when fresh, but will keep for some weeks in a cool place, if not exposed to light. To prepare the plates, flow with collodio-bromide emulsion, and when set cover for a few seconds with the chlorophyll solution, after which wash in distilled water until smooth. The plates must be used with the yellow screen, which Mr. Ives prapres by making a tank with plate-glass sides which is filled with a solution of potassium bichromate [modern equivalent; use a yellow filter]; the strength of the yellow solution may be increased or diminshed according to the subject to be copied. Excellent results have been obtained by this method.

    Many kinds of colouring matter have been used for making plates colour-sensitive, amongs them eosine, erythrosine, cyanine, fuchsin, azaline, aurantia, rose Bengal, quinoline red, chlorohpyll, xanthophyll, gallocyanic (a blue dye), chrysanaline, corallin, aldehyde green. Most of these are derived from coal-tar distillation.


    Chlorophyll; perhaps you could make this yourself Umut if you find the right plant.

    Also, found here... http://books.google.com/books?id=O3k...ophyll&f=false

    F.E. Ives, colour-sensitive plates. A compound sensibilisator of fresh blue myrtle chlorophyll with a little eosin is found to be the most sensitive to yellow and green.

    from Wikipedia - Vinca minor: Vinca minor, Lesser periwinkle and Dwarf periwinkle, is a plant native to central and southern Europe, from Portugal and France north to the Netherlands and the Baltic States, and east to the Caucasus, and also in southwestern Asia in Turkey.
    Last edited by holmburgers; 10-27-2010 at 12:52 PM. Click to view previous post history.

  9. #9
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    Chlorophyll is usable but very weak and unpredictable.

    PE

  10. #10
    holmburgers's Avatar
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    It'd be fun to experiment with though, and for the "budget-concious" it might be the absolute cheapest possible option.

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