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  1. #11

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    Quote Originally Posted by Photo Engineer View Post
    This is not film acceleration, it is rehal processing or amplification. But then it is not amplification in the strictest sense.

    This method will not get you higher speed, just higher contrast in most cases.

    Push processing of reversal films does not increase speed actually, it decreases Dmax thereby giving the illusion of increased speed in normal density areas at the sacrifice of worse color, grain and contrast.

    PE
    Thanks, it's nice to know what it's called, sometime's I see it refered to as acceleration sometimes amplification.
    What would be the proper method for film acceleration, if you dont mind me asking?

  2. #12
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    I think that you are looking to go to far. You are correct, E200 is amazing to push. It goes like a charm, but the highest I would go it 1600. Welcome to APUG!
    Helping to save analog photography one exposure at a time

  3. #13
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    Quote Originally Posted by benOM View Post
    Thanks, it's nice to know what it's called, sometime's I see it refered to as acceleration sometimes amplification.
    What would be the proper method for film acceleration, if you dont mind me asking?

    Ok, well, amplification is usually carried out on negative working systems and involves catalytic amplification of images via peroxide or cobalt hexammine.

    Hypersensitization, sometimes called acceleration is usually done on astronomical films and involves use of hydrogen gas to hypersensitize the film emulsion to extremely high speeds.

    Push processing merely takes what is there and makes it higher in contrast and foggier. In the case of the casual observer, the mid tone densities have undergone a speed change to higher values, but this is an illusion created by higher fog, contrast and in the case of reversal film the fog causes lower Dmax.

    Hope this helps.

    PE

  4. #14

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    Maybe it is called amplification, PE, but it seems that, colloquially, just like solarization, the term "acceleration" is commonly accepted for processing E-6 with a pushed first developer, re-bleaching, and then running through standard C-41.

    I am interested in the process for extreme speed situations, hopefully running medium format so that the grain isn't too extreme. I can't believe I lost that book!

    Will look for the article again, but it was a picture of a moving train at night that was stopped mid-motion that impressed me with the potential of this technique. It was, IIRC< from 1976, maybe '78 actually.

    It was the old Ektachrome 200 they were using too. New one would, hopefully, be much better! Doesn't Fuji make some kind of extreme speed 400X slide film too? Assuming similar characteristics, maybe even 200,000-speed, or an approximation thereof could be achieved.

    Exciting stuff.

  5. #15

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    Thanks, that does clear up a lot of questions. I've read a few articals about hydrogen gas sensitizing and I could not see how that and what seems to be commonly called film acceleration, which seems to just be rehal/amplification fit together. But it all makes much more sense now.

    I think I'll stick to rehal I dont much fancy mucking around with pressure pots and mixed gases for the sake of experimentation.

  6. #16
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    Karl;

    Many people call many photo processes by many names. Call it what you will, but if the guy next to you cannot understand you then you have to give details of the process and that brings you both to a common level.

    The process you describe above is one that I have never heard of, mixing C41 and E6 In fact, since the E6 and C41 process mix would not normally give the correct tone scale polarity there is obviously some detail that is omitted from your description that is critical to making it work.

    As for the rehal process, it seems integral to the process you describe, but in an obscure manner. Rehal just allows you to keep pushing dye formation. Using a C41 and E6 color developer mix may give some pretty bad crossover due to the coupler-color developer mix you are creating.

    Good luck.

    PE

  7. #17

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    Quote Originally Posted by Ektagraphic View Post
    I think that you are looking to go to far. You are correct, E200 is amazing to push. It goes like a charm, but the highest I would go it 1600. Welcome to APUG!
    I don't know about pushing E200 to 1600. I actually tried having Dwayne's push Elite Chrome 200 (the consumer version of E200) to 800. And it looked like potty - way too dark, way too much contrast, and way too magenta. Even though E200 is a professional film, I just can't imagine E200 being THAT much better.

  8. #18

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    Quote Originally Posted by Photo Engineer View Post
    Karl;

    Many people call many photo processes by many names. Call it what you will, but if the guy next to you cannot understand you then you have to give details of the process and that brings you both to a common level.

    The process you describe above is one that I have never heard of, mixing C41 and E6 In fact, since the E6 and C41 process mix would not normally give the correct tone scale polarity there is obviously some detail that is omitted from your description that is critical to making it work.

    As for the rehal process, it seems integral to the process you describe, but in an obscure manner. Rehal just allows you to keep pushing dye formation. Using a C41 and E6 color developer mix may give some pretty bad crossover due to the coupler-color developer mix you are creating.

    Good luck.

    PE
    Sorry, PE, I cannot find the article. I had it when I originally posted the article, but have looked all over and cannot find it.

    Will endeavour to look it up, but it basically was identical to what is colloquially referred to as "film acceleration" here.

    OTOMH, it referred to processing in a high-accutance B&W first developer for extended lengths (so, a classical push), then finishing up, I think, just a portion of the process, a bleach, and then running through the C-41 standard process, with room lights on.

    I think running through standard C-41, at least as a matter of convenience, was why the process was used to complete the development in '78.

    What is befuddling to me is that it yielded a negative, with no base obvioulsy, and then making up for any wierd color contrasts in printing, perhaps by sandwiching the clear-base negative with a piece of standard C-41 base mask.

    In any case, that is all I can remember without having the article in front of me.

    If you'd like, let me e-mail you scans of the photographs in the magazines; I apologize for not having scanned the article before I misplaced the book.

  9. #19
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    I have no idea of what you are trying to describe.

    A C-41 color developer is much weaker than an E6 color developer, in that the latter goes to completion. So that seems to be at odds with the process in and of itself.

    PE

  10. #20

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    PE

    See my e-mail for an example of what the process is capable of with circa 1978 Ektachrome 200.

    I don't know why they did it the way they did it. I am only reading what they wrote in the article.

    If there is a better way than the method (I think?) I correctly described from the article in the book, please let us know!

    P.S. If you could post it here (I seem unable to figure out how to do it!) I'd appreciate it.

    Apologies for the line from the crease between the pages.
    Last edited by Karl_CTPhoto; 06-13-2009 at 05:00 PM. Click to view previous post history. Reason: Additional Information

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