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  1. #21
    Photo Engineer's Avatar
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    An AhHah moment - Second try.

    I ran the first attempt posted here, on Strathmore paper, and thought that the paper fibers might be absorbing some chemicals and might also be reacting erratically. So, I repeated the experiment on Baryta paper. This scanned image still shows a bit of the negative image which is not apparent to the naked eye. Also, the hue shift across the paper is not very evident to the eye. It appears as more of a density change. So, the original looks better. Again, using PS tools I can make it look more like the eye sees it, but I think that the raw scan is the only fair way to post the example.

    There is some mottle in the high density areas. IDK if that is in the silver or dye or bleach part of the overall sequence.

    The original silver image is very sharp! The lack of sharpness in the final image indicates that there is too much silver, or too much phenazine or that the "system" needs a competer or a scavenger. Wandering phenazine in excess can drastically decrease sharpness.

    You can see how sensitive any color system is!

    Sequence at 20 deg C is as follows:

    Develop 1' Dektol 1:3
    Stop 30"
    Fix in Kodak Hardening Fixer (alum).
    Wash 10'
    Dry to examine the results
    ........................< Dye step tb posted later
    Dye Bleach 4'
    Rinse 1'
    RA4 blix 1'
    Wash 4'
    Dry
    Attached Thumbnails Attached Thumbnails Azo 2.jpg  

  2. #22

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    Again, weak on chemistry, but what about a Copper compound? Although those like to stick to just about anything and not let go easily, that would give you your cyan as well, but it might not be blue enough. CuAu? Nope, they are in the same period so they won't stick well, but they are in the same period so in theory there is a way to make Cu light sensitive. No, that's silly, but if it works put me in a footnote.
    "Would you like it if someone that painted in oils told you that you were not making portraits because you were using a camera?"
    "Shouldn't it be more about the joy of producing and viewing the photo than what you paid for the camera?"

    Me

  3. #23

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    Strange you should mention that! I think you are a bit late for that footnote!

  4. #24
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    Cuprous oxide is light sensitive and can be made into a B&W paper that is about the same speed as Kodabromide. I have several publications on that but no patent. They are in Kodak Research Disclosures. Copper salts at this level adversely affect AgX emulsions and probably cannot be used. I may have to use Calcium, Magnesium, or something stronger like Barium! The last one is probably not a good idea.

    PE

  5. #25
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    PE,
    Thank you ! This is great ! Although I personally have gone a in a different direction, your work will help many, I am sure. I have too much fascination with the gray scale color separation process to get into color emulsions myself. I have not even purchased any color film in about 5 years . But knowledge for the sake of knowledge is wonderful.
    Bill

  6. #26
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    Well, you can get a full color image from my method this way....

    Make 3 color separation negatives by exposing in-camera and developing normally.

    Then, take each separation and soak it in a dye solution so that the blue separation gets yellow dye and etc.... You may need to use a mordant or metal salt to anchor the dye in place such that you get a density of about 3.0.

    Then run the dye bleach process that I gave above for each of the 3 negatives and it will give you 3 positives.

    These, mounted in register, will give you a rather nice color transparency just as a similar method using three color developers and an appropriate set of couplers will give you Kodachrome like slides.

    PE

  7. #27
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    A 2-Color Monopack by the Dye-Bleach Method

    From Friedman's chapter on 'Gasparcolor and Silver-Dye Bleach':

    The preparation of a monopack suitable for two-color work, has also not been overlooked (USP 2028279). But instead of coloring each layer with a single dye, two are used. Thus the orange-red layer will contain pyramine orange and azo fuchsin, or azo fuchsin and mordant yellow, while the green layer will contain benzo pure blue and pyramine orange or benzo pure blue and metanil yellow. The rate at which the two dye components are acted on by the bleach solutions varies with the dyes. Thus it becomes possible to obtain dichroic effects in each layer, orangy highlights with deep red shadows in the orange-red layer, and sky-blue highlights with deep green shadows in the other. It becomes possible in this manner to obtain pleasant flesh and sky renditions, and at the same time, maintain true blacks in the middle tones & shadows. Such a process could be termed "two and one-half color."
    If you are the big tree, we are the small axe

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