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  1. #1

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    ILFORD FP-4 PLUS; CORRECTING FOR RECIPROCITY FAILURE

    Does anyone know if reciprocity failure correction computed for Ilford HP 5 Plus will apply to Ilford FP-4 Plus?

    Ilford's data sheet on these films, which declares correction factors for all its films to be equivalent, was never meant to be a precise guide, and is very old.

    In addition, does anybody know, for either of these films, what the reduction in developing time for each range of exposure increases to compensate for reciprocity failure?

    tnx

    Warren

  2. #2

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    Howard Bond's article...

    http://www.phototechmag.com/index.ph...e/reciprocity/

    ...unfortunately didn't address FP4 Plus. But it's worth a read anyway, for its insight into the utility of the manufacturers' published correction factors.

  3. #3
    Shawn Dougherty's Avatar
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    I go by the Howard Bond data for HP5+, it has worked well for me so far.
    For FP4+ I have been using the Kodak reciprocity chart for general black and white film (Not the TGRAIN CHART) and it has been working great.
    Don't forget to decrease development as well!

  4. #4

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    I use the following formula to calculate reciprocity compensation for classic Ilford films (PanF+, FP4+, HP5+):

    exposure time^1.48

    For example, a 15sec exposure after correction will result in a 55sec exposure. I found this works well.

    I don't remember where I picked this up, but thanks to whoever came up with it originally.
    And the sign said, "long haired freaky people need not apply"

  5. #5

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    Re: Recip Failure and FP-4 Plus

    Thanks for the quick and thoughtful responses.

    Oren: I have read Bond's article. I trust him implicitly and rely on that article--or as much of it as I can handle. Which is why I'm so down on the Ilford figures.

    Walter: I believe that ^1.48 is the Ilford formula precisely. I can't imagine how it can work for all the films they list it for. I'm afraid I'm not going there.

    And Shawn:
    I'll take a look at those Kodak figures, but I'm curious to know why you've never given the Bond figures a run with FP-4+. If you ever do, I'd love to hear about it. I think Bond might, too.

    tnx

    Warren

  6. #6

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    Quote Originally Posted by Shawn Dougherty View Post
    I go by the Howard Bond data for HP5+, it has worked well for me so far.
    For FP4+ I have been using the Kodak reciprocity chart for general black and white film (Not the TGRAIN CHART) and it has been working great.
    Don't forget to decrease development as well!
    Quick further question, Shawn:
    At what ASA do you shoot FP-4+ and what is your normal developer and development time?
    tnx
    Warren

  7. #7
    Shawn Dougherty's Avatar
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    Quote Originally Posted by wskmosaic View Post
    And Shawn:
    I'll take a look at those Kodak figures, but I'm curious to know why you've never given the Bond figures a run with FP-4+. If you ever do, I'd love to hear about it. I think Bond might, too.

    tnx

    Warren
    As far as I know Bond did not work with FP4+ or I certainly would.... If I'm missing it somewhere please point it out!


    Quote Originally Posted by wskmosaic View Post
    Quick further question, Shawn:
    At what ASA do you shoot FP-4+ and what is your normal developer and development time?
    tnx
    Warren
    I rate FP4+ @ ISO 64. However, I tend to error on the side of more exposure. I am developing FP4+ in Pyrocat HD at 1:.5:100 (note that B is POINT FIVE ((.5)). 8 Minutes for N. I develop 4x5 in small tubes gently rolling them in water. And I stress the importance of using N- development in various degrees for reciprocity corrected exposures.

    Edit. HERE is a link to the Kodak graph I have been using for FP4+, it is on page 3.
    Last edited by Shawn Dougherty; 04-03-2012 at 12:28 PM. Click to view previous post history. Reason: Added Kodak Link

  8. #8

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    Quote Originally Posted by Shawn Dougherty View Post
    As far as I know Bond did not work with FP4+ or I certainly would.... If I'm missing it somewhere please point it out!

    I'VE SEEN SEVERAL SETS OF DATA FOR FP-4 PLUS, AFTER MUCH SCROUNGING, SURFING AND ASKING. ONE IS AT
    http://www.film-and-darkroom-user.or...an+reciprocity , THOUGH YOU MIGHT HAVE TO LOG IN TO THE FDU FORUM TO SEE IT. IN A PINCH, AT THAT FORUM, SEARCH 'McLEAN RECIPROCITY TO COME UP WITH IT.

    THE OTHER IS ASCRIBED TO JOHN SEXTON AND LOOKS LIKE THIS (METERED/ADJUSTED):

    2/3
    4/7
    8/19
    12/33
    16/50
    24/93
    32/145
    45/250
    60/378
    90/853
    120/1670

    THEY BOTH APPEAR TO BE MORE GRADUAL THAN THE KODAK DATA AND CONSEQUENTLY APPEAR NOT TO REQUIRE SO MUCH (IF ANY EXCEPT AT THE LONGEST EXPOSURES) REDUCED DEVELOPMENT.

    AT LEAST THAT SEEMS TO BE THE CONSENSUS; I'M ABOUT TO LAUNCH MYSELF INTO THEM.




    I rate FP4+ @ ISO 64. However, I tend to error on the side of more exposure. I am developing FP4+ in Pyrocat HD at 1:.5:100 (note that B is POINT FIVE ((.5)). 8 Minutes for N. I develop 4x5 in small tubes gently rolling them in water. And I stress the importance of using N- development in various degrees for reciprocity corrected exposures.

    Edit. HERE is a link to the Kodak graph I have been using for FP4+, it is on page 3.
    AND THANKS FOR THE KODAK GRAPH; I HAVE THEIR DATA.

    AND THANKS FOR ALL YOU HELP.


    WARREN



 

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