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  1. #11
    David Lyga's Avatar
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    Ok thank you all: I wondered if anyone had had direct experience. I have lots of experience with Farmer's and I do expose adequately and overdevelop but it is always a race between the fog increasing and the highlights increasing. The fog often wins the race. - David Lyga

  2. #12
    Rudeofus's Avatar
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    With a bigger than normal amount of restrainer you should be able to reduce fog much more than highlights. This way you lose speed but gain contrast.
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #13
    David Lyga's Avatar
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    Rudeofus, I woke up at 4 AM this morning and, without having read what you just wrote, did what you just said. I have a stock of one percent benzotriazole and added about 35 ml of the stock to a liter of diluted (D-76 type: 1 + 3) working solution developer. I processed the Eastman 4x (ancient with fog) for 15 minutes at 100 F (!) at EI of 2 (!) and I could not believe how beautiful my negatives were! Almost fog free and the only 'bad' part was a bit of blocked up highlights due to the gross overexposure. Shadow detail and contrast were just about perfect.

    This was a LOT of restrainer to use and it worked as I had hoped. Thank you and I hope others try this because the film was just about hopeless. It requires an amazing amount of exposure but, if used on a tripod, my 100 foot roll is fine. Best of all: given that this is a very high speed-designated film, I can say to all that there most likely will NEVER be a B&W film in your possession that you will ever have to throw away. I also tried the Kodak 2484 and got the same spectacular results. - David Lyga

  4. #14
    Truzi's Avatar
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    Just out of curiosity, what (if anything) would happen if you added the restrainer but your film was not fogged (in other words, fresh-dated film)?
    Truzi

  5. #15

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    Generally speaking, from a sensitometric perspective (image structure characteristics are another story) adding a restrainer, or more restrainer to a developer that had already been balanced, will tend to reduce film speed.

  6. #16
    David Lyga's Avatar
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    Truzi, nothing bad would happen to restrainer used when film was not fogged other than development would take longer. Restrainer slows down development, especially the lowest densities, but since the lowest densities (fog) would not be there, the negative would develop normally or maybe a tiny bit more contrast than usual. As Michael says: It 'tends' to reduce film speed but, Truzi, only because development takes longer and (only a tiny bit) because the shadow densities are now very slightly suppressed with the restrainer. -David Lyga

  7. #17
    Rudeofus's Avatar
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    David, what is overshadowed by fog in your film could hold image detail in new film. In other words, fog did on the whole surface what proper exposure would do selectively, and by eliminating fog you also eliminate details in low exposure areas that could be there if you used less restrainer and new film stock.

    Restrainers do reduce film speed but sometimes that's what it takes.
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #18

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    While an acidified ammonium thiosulfate solution will act as a bleach the action is fairly slow. Thus Haist recommends a pH of 4. The only problem is that acidified thiosulfate solutions are unstable and the lower the pH the faster they sulfurize. So the pH of 4 is probably a compromise between bleaching rate and stability. Still I don't see such a bleach as competing with Farmer's. Ilford in their book on photochemistry gives a large number of bleach formulas for the three difference bleach types, sub-proportional, proportional, and super-proportional.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  9. #19
    David Lyga's Avatar
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    Rudeofus:This is why one must expose for shadow detail well into the middle of the characteristic curve, because the fog occupies the first half of that curve! With heavily age-fogged film the threshold is in the middle of that curve.

    This is why some fast, but age-fogged, films like Kodak 2484 and Easman 4x, will then have highlight detail that is rather contracted and not nicely separated. The highlights have to be 'forced and compacted' in order to allow shadow detail to be registered. That is one of the trade-offs to getting such films to 'perform'.

    Gerald: Thank you: so the enigma is really not so arcane: it's only acid that is needed to cause the fixer to become a reducer. (Apparently, there is nothing so special about the 'citric' type?) I will never forget an incident that happened back in the 60s when I was a teen-ager, about 15. I used #2 Kodabromide for paper and was very naive about darkroom matters. I processed the print but it was a tiny bit too dark. My mother called me for lunch and I simply left that print in the full strength fixer (Kodak Fixer powder did not differentiate between film and paper fixer: they were the same strength). After lunch I went down to the basement to my darkroom and was flabbergasted to find a print in the fixer that had the most beautiful tones that I had ever seen. The acid fixer had 'reduced' the density and did so in a 'cutting' fashion that yielded such beautiful tonality and rich contrast. I will never forget that print. - David Lyga

  10. #20

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    Quote Originally Posted by David Lyga View Post
    Gerald: Thank you: so the enigma is really not so arcane: it's only acid that is needed to cause the fixer to become a reducer. (Apparently, there is nothing so special about the 'citric' type?) I will never forget an incident that happened back in the 60s when I was a teen-ager, about 15. I used #2 Kodabromide for paper and was very naive about darkroom matters. I processed the print but it was a tiny bit too dark. My mother called me for lunch and I simply left that print in the full strength fixer (Kodak Fixer powder did not differentiate between film and paper fixer: they were the same strength). After lunch I went down to the basement to my darkroom and was flabbergasted to find a print in the fixer that had the most beautiful tones that I had ever seen. The acid fixer had 'reduced' the density and did so in a 'cutting' fashion that yielded such beautiful tonality and rich contrast. I will never forget that print. - David Lyga
    Thiosulfate bleaching action is proportional to acidity, and gives proportional bleaching, not cutting.

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