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  1. #31
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    Couplers are not mordants.

    Mordants are chemicals that hold soluble dyes in place in some material such as cloth or film. Couplers are materials that form dyes through a two step or three step process involving a reducing agent and an oxidizing agent. In film, this is the Silver Halide and the developing agent.

    PE

  2. #32
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    It'll be interesting to see if the toners can do the trick; maybe so! There were a couple dye-toning tri-color processes too, so it just goes to show you that toners can create a wide range of usable colors.

    I've not really looked at the mordant processes seriously yet (in terms of the procedure) so I can't be certain when in a reversal process you'd wanna stick it. I think though, that you'd need to develop up the positive silver before you could turn it into the potassium iodide mordant, viz. the Ives process.

    Finding dyes for this might not be hard. There are a thousand basic dyes on eBay that are used in biological staining and other things. Malachite green is one from the top of my noggin.

    Alternatively, if you look at Capstaff's patents on this process, his method for sticking the dye in the gelatin is by a dichromate bleach not unlike one found in reversal processing or carbro. Heck, the first patent (IIRC) goes from a negative to a dyed positive via this bleach in one step. He later patented a method to do this from a positive to a positive (better for printing to movies).

    Although chrome salts can be mordants, in this instance it's not strictly lending any mordant action, but rather it's the hardening differential set-up in gelatin that "involves" the dye. This requires acid dyes, loosely speaking, that might easily be found in the textile industry.

    Sorry if I'm repeating myself a bit; some tricky concepts here, and I don't think it hurts to reiterate and say things differently. It certainly helps me make sense of it all too...

    In the end, I hope you give it a go with any method you like!

  3. #33
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    This is a really amusing little multimedia thing from PBS. It actually takes you through making a Capstaff Kodachrome... well kind of.

    Anyways, pretty cool, check it out.

    http://www.pbs.org/wgbh/amex/eastman...odachrome.html

  4. #34
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    Yeah, it's kind of juvenile for sure, but I was amazed that this fairly esoteric process had it's own multimedia thingy.

    You raise a good point though, we haven't really discussed the "taking" mechanism for this process at all. We've just taken for granted that we have 2 separations.

    And to be honest, I don't know how they secured these seps! I believe that at some point, particularly with movie film, that they used a "duplitized" film stock, that is, 2 emulsions coated on either side of the film & appropriately sensitized. Then for processing, either side was floated on the appropriate dye bath.

    But as for the big glass plates... anyone know?

  5. #35
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    I have never seen anyone make a Capstaff film, but I just finished watching some motion picture footage of Capstaff himself playing himself and a movie starlet! He really dressed the part! And, he and his friends had a lot of fun.

    PE

  6. #36
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    That's hilarious.. did you see a projection of the original film, or a reproduction of some sort? Only in Rochester!

    I guess Capstaff's grandson is a painter in the Rochester area; he's got a blog somewhere and he talks a bit about both of his grandfathers. The other was a painter; so, also into color but from a different perspective.

    What greater gift than to see in color!
    If you are the big tree, we are the small axe

  7. #37
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    This was a film with Capstaff, Sheppard, Trivelli, Ross, and Mees among others. It was very well done and very funny. Narration was by Dr."Knobby" Clark.

    PE

  8. #38
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    Amazing.. that sounds like a treasure.

  9. #39
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    Hmmm, holographic plates aren't cheap and they're as slow as molasses, if not slower. This seems a bit like going to the moon by way of Venus! If 4x5" or 8x10" film sags too much for registration, maybe you could sandwich them between two pieces of glass and shoot them in a spring-plate pressure plate.

    For me, figuring out the dye process is paramount and everything else is secondary, but I can't fault you for being imaginitive.
    If you are the big tree, we are the small axe

  10. #40
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    An in-camera exposure on a holographic plate is going to be something like 2 minutes at f/8 in bright sunlight, or at least that's what it takes for a Lippmann developer (post #70).

    A much simpler approach would be to take sequential exposures of a still-life, and/or, make separations of the red & green from regular color film.

    You should look into true color toning, where the silver becomes C/M/Y. There was a process called Defender Chromatone that used this method. Unfortunately, the toning solutions where proprietary, but I think there are some formulas in Friedman's History.



 

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