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  1. #21
    Photo Engineer's Avatar
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    It isn't the Ag Bill, it is the denity and contrast.

    RA4 transparency materials were not built for use of just the silver image alone. The only way to find out is try.

    PE

  2. #22
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    Howdy T-grain,

    A very interesting idea for sure. However, it seems a bit like going from LA to New York by way of Anchroage... ok, maybe not that far, but...

    The advantages that I see are the ability to use a safe-light and the cost, if indeed you can buy transparent RA-4 materials on the cheap. To me, it seems like that would actually be expensive... but I have no idea, I haven't looked into that at all.

    I also suspect that a slide wouldn't be too well suited for a negative material. Can anyone comment on the typical density range of a color negative & and a color slide? If I'm not mistaken, a C-41 negative is fairly low in contrast comparitively and the RA-4 materials are tuned accordingly. But like you said, perhaps there could be some flexibility in the b&w developing stage.

    The ironic thing is that one is using a color material to make b&w separation negatives to be used in a color assembly process. I'm no stranger to that though... using E6 screen plates to make color photos with b&w film.... but if the ultimate goal of these alternative color processes is to free ourselves from the chains of commercial color products, this wouldn't work.

    But that's not meant to discourage you at all! It's clear that your brain is going to new places and that you're getting creative and highly original ideas.

    I guess the crux of your suggestion is this; are tranparent RA-4 materials the cheapest panchromatic material (on a clear base) that you can get? If so, it just might be practical.
    If you are the big tree, we are the small axe

  3. #23

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    It isn't the Ag Bill, it is the denity and contrast.



    PE[/QUOTE]

    I thought that was my point.

  4. #24
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    Sorry if I misunderstood. My point was that RA4 materials are not noted for giving high density Silver images, just dye images. And therefore the density might be too low to be used in this context. IDK.

    PE

  5. #25

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    Quote Originally Posted by Photo Engineer View Post
    Sorry if I misunderstood. My point was that RA4 materials are not noted for giving high density Silver images, just dye images. And therefore the density might be too low to be used in this context. IDK.

    PE
    Ok, Ron, so there wouldn't be any problem if a chromogenic (RA4) developer is used and then a BW fixing, so a negative would be made of silver+dye?

  6. #26

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    thanks for your appreciation, Chris!
    but I think if this RA4 thing would work (and being not too expensive), it is more like a straight route from slide directly to the contact negative....
    I still need to check the availability and price at the local Kodak dealer here in Slovenia. Ordinary RA4 paper isn't expensive, but have no idea how much would be the transparent version.
    as for its contrast, maybe it could be tamed at least to a degree, but this doesn't worry me, since the carbon tissue material could be tuned accordingly (dichromate and pigment concentration)-remember, it's a very flexible process!
    as for the dependency from commercial products-yes, but nonetheless we are (still) also dependent on color films.....

  7. #27

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    just checked the Endura datasheet-I would say it has a gamma of around 2....quite contrasty I would say.....but that would be at 35 deg Celsius
    I just wonder how it would behave in a diluted developer and at 20 degrees in a tray

  8. #28
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    The reported gamma is for the dye image alone. Dye plus silver would be higher and lower in saturation. You might want to form a neutral dye image. IDK.

    PE

  9. #29
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    Quote Originally Posted by T-grain View Post
    but nonetheless we are (still) also dependent on color films.....
    That's very true. But a three-color camera project is inevitable one of these days (years, decades)....
    If you are the big tree, we are the small axe

  10. #30

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    Quote Originally Posted by Photo Engineer View Post
    The reported gamma is for the dye image alone. Dye plus silver would be higher and lower in saturation. You might want to form a neutral dye image. IDK.

    PE
    one more question, Ron-how do behave the three color curves (the slope) when you alter the temperature/dilution of the selected developer? do they become unpredictable? I know you have vast experience with RA4 at room temp

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