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Thread: Perceptol in Jobo

  1. #1

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    Perceptol in Jobo

    I have been using HC-110 to develop sheet film in a Jobo but I have trouble getting N minus development because the developing times just get too short. I just don't think I can trust it to be consistent at very high dilutions and very short development times.

    In any case, I have been thinking about another developer for rotary processing, possibly D76, but also Perceptol for no other reason than Perceptol seems to have very long development times which would give me a little room at the bottom end.

    Have any of you used Perceptol in a rotary processor?

  2. #2

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    Re: Perceptol in Jobo

    Quote Originally Posted by docw View Post
    ...Have any of you used Perceptol in a rotary processor?
    Yes, I recently established EI and developing time for TMY-2 in Perceptol 1+1. After a five minute presoak, my results for 4x5 sheets in a 3006 Expert drum at 45 rpm were speed 320, contrast index 0.55, time 5 minutes 40 seconds at 75 degrees F. Beautiful tonal scale, great sharpness and very low grain.

    I pursued this combination in order to avoid the higher EI other developers provide so that, under the bright, sunny conditions prevalent here, Copal shutters' highest speeds (never accurate) aren't necessary.

    Be sure to use at least 250ml of stock solution per 80 square inches of film.

  3. #3

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    Re: Perceptol in Jobo

    Thanks Sal. I am assuming that the time you give (5'40") is for normal development. For me, this means that shorter times for N minus development might be too short. I notice that you are developing at 75F while I usually develop at 68F. Perhaps this will give me more time and perhaps I can also use a higher dilution, but I wonder if this will put me in the same situation as with HC-110.

  4. #4

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    Re: Perceptol in Jobo

    Quote Originally Posted by docw View Post
    ...I am assuming that the time you give (5'40") is for normal development...
    Yes, Contrast Index 0.55 is "N."

    Quote Originally Posted by docw View Post
    ...I notice that you are developing at 75F while I usually develop at 68F. Perhaps this will give me more time...
    I standardize on 75 degrees F to cope with the high ambient water and air temperatures here much of the year. Since Perceptol is a single-component developer, it should follow Ilford's time/temperature adjustment chart fairly closely. Therefore, at 68 degrees F, my time ought translate to a bit over eight minutes.


    Quote Originally Posted by docw View Post
    ...perhaps I can also use a higher dilution...
    Slightly more than eight minutes for "N" should permit you enough shortening leeway to achieve "N-minus" contrast without risking uneven results. If your testing reveals it does not, more dilution is another option. Just be sure to use at least 250ml of stock solution per 80 square inches of film regardless of dilution.

  5. #5

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    Re: Perceptol in Jobo

    Sal - Are you using a JOBO? If so, which of the settings (P,F, 1-7) translates to 45 rpm? Do you set it so it rotates in one direction or changing direction?

  6. #6

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    Re: Perceptol in Jobo

    Quote Originally Posted by Doug Herta View Post
    Sal - Are you using a JOBO? If so, which of the settings (P,F, 1-7) translates to 45 rpm? Do you set it so it rotates in one direction or changing direction?
    I have and use both JOBO CPA-2 and CPP-2 processors. I always process with the drum alternating, not going in a single direction. To know which setting on your processor will provide a specific drum rotation speed, see this post:

  7. #7

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    Re: Perceptol in Jobo

    Here are a few follow-up question. In doing some more reading on this, I discovered that D-23 is very similar to Perceptol, but even more simple to make (just Metol and sodium sulfite!). Anchell says in his "Darkroom Cookbook" that the developing time for ISO 100 films (I am shooting FP4) is 5'30' in D-23 1:1. He triples this time for a 1:3 dilution. This would have to be decreased for a rotary processor but with developing times that long, my Normal development time will very likely still give me a lot of room.

    So, how much D-23 at 1:3 do I need for one sheet of 8x10?

  8. #8

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    Re: Perceptol in Jobo

    Quote Originally Posted by Sal Santamaura View Post
    ...Perceptol is a single-component developer...be sure to use at least 250ml of stock solution per 80 square inches of film regardless of dilution.
    Quote Originally Posted by docw View Post
    Here are a few follow-up question. In doing some more reading on this, I discovered that D-23 is very similar to Perceptol, but even more simple to make (just Metol and sodium sulfite!). Anchell says in his "Darkroom Cookbook" that the developing time for ISO 100 films (I am shooting FP4) is 5'30' in D-23 1:1. He triples this time for a 1:3 dilution. This would have to be decreased for a rotary processor but with developing times that long, my Normal development time will very likely still give me a lot of room.

    So, how much D-23 at 1:3 do I need for one sheet of 8x10?
    Perceptol is very much like D-23 with sodium chloride added. D-23 and Perceptol both require 250ml of stock solution to reliably develop 80 square inches of film. You'd need a full liter of dilute (1+3) D-23 working solution for one sheet of 8x10.

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