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  1. #71
    Photo Engineer's Avatar
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    Strictly speaking, Iodide is not a ligand. It will form a true salt with silver ion. It is not ideal in that it forms the Silver salt, forms HI and is oxidized to the Iodate. I am not aware that it is used in the modern bleach due to the difficulty of fixing out AgI. Improperly fixed Ilfochrome prints show yellow highlights of unfixed AgI, and all prints kept over a long period of time have a mild residual acidic odor even with extended wash times.

    In addition, Ilfochrome uses a patented multilayer structure to reduce contrast.

    In traditional Ciba bleach, it contained Sulfuric Acid which forms the soluble Silver Sulfate during bleaching and thus the bleach acts in some regards like a blix. The newer bleach uses sulfamic acid which also forms a soluble salt with Silver ion.

    PE

  2. #72

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    Actually, the currently-shipping, all-liquid kit is back to sulfuric. The prior liquid/powder kit had sulfamic.

  3. #73

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    Yes Dr. No....you are correct. Also, iodide and/or iodide-bromide mixtures have been ubiquitous in Cibachrome and Ilfochrome formulations as the silver salt-formers. Thus, given the low solubility product of AgI, I do not believe that silver sulfate has anything but a fleeting existence. Highlights are always yellow (AgI) post-SDB and high concentrations of ammonium thiosulfate are needed to fix quickly. The internal masking system does reduce contrast slightly, but its major function is to correct for unwanted dye absorptions. There is most definitely further contrast control via the aforementioned competitive process in the SDB bath itself.

  4. #74

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    Hello,

    I'm an italian professional printer; I'm working with my friend brooks to his ilfochrome home brewed system and I would like to let you know that first results are GORGEUS !

    I invested my time and some money in this project but no regret at all. We started from fuji velvia 50, one of the hardest slide to reproduce with a proper color balance due to known crossover problems (cyan highlights, magenta shadows). The first results are so exciting that we decided to go deeper trying not only to make it a real alternative to ilfochrome but also improving it.
    In fact we are going to start right now the "fine tuning" step; one of the most interesting aims of this step is modulating the contrast grade so that you can pair it with the kind of paper you are using (clm.1k or cps.1k) building some kind of "chemical contrast reduction mask".

    Thanx brooks for giving me the right incentives to keep on being so excited in my "beta tester" position...


    cheers!
    plus

  5. #75

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    Good to hear it...looking forward to hearing more news on this.

  6. #76

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    Any progress, guys? What are you using for the catalyst?

  7. #77
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    Quote Originally Posted by plus View Post
    Hello,

    The first results are so exciting that we decided to go deeper trying not only to make it a real alternative to ilfochrome but also improving it.
    In fact we are going to start right now the "fine tuning" step; one of the most interesting aims of this step is modulating the contrast grade so that you can pair it with the kind of paper you are using (clm.1k or cps.1k) building some kind of "chemical contrast reduction mask".

    plus

    This all sounds very interesting but when delving into specific tasks like this its important to be able to reproduce and have control (keep online) whats being done. Are you now running ilfochrome control strips for your testing and measuring results via densitometer? or are you using any of the other ilfochrome process control products?
    "Its my profession to hijack time" ~ Stephen Frizza.

  8. #78
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    I have posted a generic formula using Phenazine. By tweaking coating parameters I could make a 3 color dye bleach multilayer, but if I were to be forced to use Ilfochrome, then the bleach solution would have to be tweaked.

    PE

  9. #79

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    Hi there,

    we are using stouffer 21 step wedge tests strips obviously (unfortunately I got no densitometer); right now we are waiting for some chemicals to arrive so we are forced to have a break.... As living in the old europe (Italy) I'm experimenting some difficulties to obtain some raw chems but I'm a bullheaded guy so nothing is really insurmountable
    We are using quinoxaline as catalyst agent.
    Stay tuned and be patient too ...
    Have an happy new year guys.
    PEACE.

  10. #80
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    This is an exciting thread. I haven't read the middle pages, just the first and last, but I'm interested to know more. Later this evening when I'm not taking up company time I will read the rest!

    I got a stack of Ilfochrome paper from an oldtimer too disabled to lean under his enlarger and lean over to soup chemicals. Would be nice to put it to some use. I've got a stack of 4x5 slides (mostly Ektachrome E100VS) I would love to print.
    I love the wilderness and I love my trail cameras, all Fuji's! :) GA645, GW690 III, and the X100 which I think is the best trail camera ever invented (to date).

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