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  1. #41
    Bill Burk's Avatar
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    You'll soon find out first-hand when you print your negatives. I think you will find you would have preferred them to be less dense. There will be some, uh, qualities that will make your prints different from your usual. The most significant degradation (and it is a graceful degradation) will probably be some "halation", reduced clarity and some excess grain.

  2. #42
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    Quote Originally Posted by markbarendt View Post
    The curves for TXP aren't showing it reaching D-max so, no to that part at least.

    TMY can hold about 14 stops on the straight line IIRC, so if you had used TMY instead of HP5 for the shots that started this thread you could have exposed another three stops (7 stops up total) before you even got to the shoulder let alone finding D-max. So again no, the generalization doesn't work.

    Hi Mark. I think you are missing my point. Here is how I would conduct the experiment so that a generalisation can be made about the curve shoulders for at least a few popular films and developer combinations:

    1. Pick one of the 5 most popular B&W panchromatic films.
    2. Pick one of the 5 most popular film developers.
    3. Expose the film to a step tablet with sufficient intensity that causes Dmax to be reached and entered into by at least 1 stop (this guarantees you WILL eventually traverse the shoulder even if you can't find it in the published curves) when it is developed.
    4. Develop the roll for some minimum time which ensures a CI beginning at say 0.3 and that Dmax is reached because it was overexposed so much in step 3.
    5. Repeat the above steps, increasing the dev time to give increases in CI of reasonable steps (say 0.1 or 0.2) until you reach a CI of say 1.0.
    6. Plot all HD curves for that combo on one page.
    7. Repeat all above steps for a few more film+dev combos.
    8. Make a general statement about what you observe in the shoulder areas of all the curve sets.


    regards
    Peter

  3. #43
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    Peter,

    I understand your idea.

    I do think you have your work cut out for you to make it real; first in finding, then in mapping the shoulders.

    Personally I doubt that you find a clear cut shape or threshold that defines shoulders in general in a meaningful way.

    Consider D3200, it has a long arc of a shoulder, depending on the CI you might consider "normal" the shoulder can even make up most of the curve. XP2's curve is similar in shape. Like the energizer bunny they just keep going and going.

    Click image for larger version. 

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    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  4. #44

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    Whenever I have tested films/developers I have always tested including the shoulder region because it is important in my work. I've done this with several films and developers - over and over. There are quite a few variables to consider and both the shape of the shoulder and where it begins are subject to manipulation. The only rough generalization I would make is that the films I've tested tend to exhibit their longest straight lines when developed to an approximately normal CI. Underdevelopment tends to shorten the straight line due to increasing compression on both ends, and gross overdevelopment moves the shoulder to the left for obvious reasons. On the underdevelopment side, different developers and techniques can have some effect on the curve shape.

    I would suggest you simply move on from your overexposure error.

  5. #45
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    Quote Originally Posted by Michael R 1974 View Post
    I wouldn't suggest that. Soft working developers and/or reduced agitation can make the film shoulder earlier. That's exactly what Peter doesn't want.

    Edit: this is a response to post #23.


    I was trying to reduce effective film speed not rescue a 4 stop overexposure with mathematics and theory
    I'm beginning to wonder if there is any roll of film
    losing film speed would be my first action before heading into all this graphing of whatever you're doing
    if you use xtol at 400 you can use 250 with rodinal
    add in restrainer and you could use 200
    maybe add in enough and you could have a film speed drop from 400 to 100
    more? don't know. At some point you wouldn't develop that latent image at all or so I've read

    with that much restrainer you'd likely have to reduce development to tame the contrast from its addition


    drop film speed enough and print on azo or alternative process



    I'll include a pic of 3 4x5 negatives taken on badly fogged film. I was trying to reduce fog through restrainers
    all exposed at ASA10 in Rodinal 1:20
    upper neg had some restrainer
    right neg had more
    left had even more

    as you can see the fog nearly disappeared and it seems the effective film speed was dropped probably from 40-50 at foggiest/most dense to about what I shot it at 10

    i'll take a quick pic of the straight print using no filter "Grade 2"
    detail from slightly smaller than 20x24 print
    Attached Thumbnails Attached Thumbnails versapan.jpg   detail.jpg  

  6. #46
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    Quote Originally Posted by Michael R 1974 View Post
    Whenever I have tested films/developers I have always tested including the shoulder region because it is important in my work. I've done this with several films and developers - over and over. There are quite a few variables to consider and both the shape of the shoulder and where it begins are subject to manipulation. The only rough generalization I would make is that the films I've tested tend to exhibit their longest straight lines when developed to an approximately normal CI. Underdevelopment tends to shorten the straight line due to increasing compression on both ends, and gross overdevelopment moves the shoulder to the left for obvious reasons. On the underdevelopment side, different developers and techniques can have some effect on the curve shape.

    I would suggest you simply move on from your overexposure error.
    I have done the deed. Developed at N-0.5, and............ they look very printable ! I will measure the max density when negs are dry tomorrow but it looks to be between about 1.7 and 1.9 which is roughly what I predicted given my process and kept me away from the theorised shoulder section at 2.1.

    Thanks for your generalisation Michael. One day I might plot the HD curves for HP5 out past the shoulder as I am still convinced that for a given overexposure scenario it is possible to avoid a small encroachment into the shoulder (from the straight line region) by reducing dev time by one "N step".

    Thanks to everybody else for your suggestions.

    regards
    Peter

  7. #47
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    Peter - Congrats! I am a mere mortal and don't get all this N-x talk, though, I do know AA's texts contain the whole explanation, however, in an effort to make this thread something mortals can follow, would you mind "101'ing" it? Like real brief, for eg, I over exposed by x stops and to compensate I developed in this manner..... Nothing fancy, just like "for those following along at home who might not be Zone folks I used D76 and agitated...."

    That way many can use your real world issue and kind of back into what was theorized and eventually seen. Books are great but real world examples and discussions are even better (sometimes)....

  8. #48

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    Quote Originally Posted by PeterB View Post
    I have done the deed. Developed at N-0.5, and............ they look very printable ! I will measure the max density when negs are dry tomorrow but it looks to be between about 1.7 and 1.9 which is roughly what I predicted given my process and kept me away from the theorised shoulder section at 2.1.
    Peter
    Keep in mind a fixed density (2.1 in this case for HP5) does not define the beginning of the shoulder. You're basing that on a curve, and it applies only to that curve (ie a specific developer, process and contrast).

    It may also be worth mentioning it is difficult to say how much "overexposure" was given. Based on what? And how did we meter the scene? Etc.
    Last edited by Michael R 1974; 05-29-2013 at 10:38 AM. Click to view previous post history.

  9. #49
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    So Michael, per chance have you done plots on HP 5?
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  10. #50

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    I haven't worked with HP5. Sorry.



 

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