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  1. #1
    Rudeofus's Avatar
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    Where's the shoulder in the film data sheets?

    If I look at the data sheets of current b&w film stock as published by Kodak, Fuji and Ilford, they all contain characteristic curves which show the whole toe but never the shoulder. For some reason all these published characteristic curves stop somewhere in the straight section.

    Given how much fuzz most reputable b&w photography books make about the shoulder of film, is there a special reason the shoulder is not shown in data sheets?
    Trying to be the best of whatever I am, even if what I am is no good.

  2. #2
    David Lyga's Avatar
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    That is a good question and maybe both of us are wholly naive. But...perhaps there is far more importance in establishing the threshold of exposure (toe) and that the 'flattening out' with excess exposure comes about ONLY with too much exposure. With films like microfilm (ie, Kodak's ImageLink) there is not enough latitude for both shadow detail and highlight detail. You must choose one or the other. But with films like Tri-X, HP-5+, etc, there can be an abundance of overexposure before the shoulder flattening becomes too apparent.

    If I make no sense perhaps someone will come to our collective rescue. - David Lyga

    MODERATOR: I cannot remove the double 'there' in my second sentence. In the 'edit' mode only one appears and if I remove that one, none remains. - David Lyga

  3. #3

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    Quote Originally Posted by David Lyga View Post
    MODERATOR: I cannot remove the double 'there' in my second sentence. In the 'edit' mode only one appears and if I remove that one, none remains.
    Refresh your page. (IAmNotAMod)

  4. #4
    David Lyga's Avatar
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    Sorry, I am too stupid and don't know how! - David Lyga

  5. #5

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    Usually it is Shift F5. But in any case, explore the menus of your browser, something you should have done a while ago. Look for "Refresh" or "Reload". Do it when you have this page open (not editing).

    In the recent FireFoxes, it is not in the menu, but Shift F5 works. In any case it is in the toolbar as a circular arrow.

  6. #6
    ic-racer's Avatar
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    Quote Originally Posted by Rudeofus View Post
    If I look at the data sheets of current b&w film stock as published by Kodak, Fuji and Ilford, they all contain characteristic curves which show the whole toe but never the shoulder. For some reason all these published characteristic curves stop somewhere in the straight section.

    Given how much fuzz most reputable b&w photography books make about the shoulder of film, is there a special reason the shoulder is not shown in data sheets?
    The usual 21 step wedge does not give enough datapoints to show both the toe and shoulder on modern films. I have used a wide 21 step wedge that was half-sandwiched with a strong ND filter to try and make "complete" curves.

    Sure, people post about "The Shoulder" but sometimes it is crazyass stuff. For example the guy exposing T-max 400 at ISO 3200 shooting with a hazy f1.2 lens from e-bay wide open with a dirty "Skylight filter" (maximum flare condition & severe underexposure) and worrying about his highlights on the shoulder. Under those conditions the highlights are likely to fall TEN or more stops from the shoulder.
    Last edited by ic-racer; 09-15-2011 at 04:48 PM. Click to view previous post history.

  7. #7
    Rudeofus's Avatar
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    Quote Originally Posted by ic-racer View Post
    The usual 21 step wedge does not give enough datapoints to show both the toe and shoulder on modern films. I have used a wide 21 step wedge that was half-sandwiched with a strong ND filter to try and make "complete" curves.
    And I'm quite sure that Kodak, Fuji and Ilford have better tools available than limited range step wedges and ND filters. And even in the absence of such tools you can create the full curve with two or three separate measurements. It may be less neat that way but it's just for a data sheet after all. The curves in the data sheets end at densities below 3, even a 200€ flat bed scanner could measure this.
    Quote Originally Posted by ic-racer View Post
    Sure, people post about "The Shoulder" but sometimes it is crazyass stuff. For example the guy exposing T-max 400 at ISO 3200 shooting with a hazy f1.2 lens from e-bay wide open with a dirty "Skylight filter" (maximum flare condition & severe underexposure) and worrying about his highlights on the shoulder.
    Even Ralph Lambrecht and Ctein write about the shoulder and the importance of its shape, so this topic is not exactly reserved for a bunch of clueless freaks ...

    There are some situations where I would really like to know in advance how certain films are going to respond to severe local overexposure, e.g. any scene including the sun during broad daylight or any scene including the moon at night.
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #8
    Photo Engineer's Avatar
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    If you look at a standard H&D curve, for negative films the shoulder is on the right where the straight line ends and density levels off. On reversal films, the shoulder is on the left where density levels off. Usually, this is about D=3.0 but in negative films and MP print films it can be higher or it may not even be present due to extreme latitude.

    PE

  9. #9

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    I prefer to do my own tests and do them in-camera with a white/grey card. I plot from threshold up to 10 stops above metered (once I've determined my exposure index). It gives me a full scale curve. Personally I've never found the H&D curves in Kodak, Ilford, or Fuji datasheets to be of much use.

  10. #10
    Michel Hardy-Vallée's Avatar
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    It sort of depends on the film and on the way the manufacturer plots their graphs.

    If you look at the curves in attachment here, Plus-X has a clear shoulder, followed by Tri-X. Then PanF+ has a very gentle shoulder (use a straight line to compare) and HP5+ has almost no visible shoulder.
    Attached Thumbnails Attached Thumbnails PanFplus.png   Plus-X.png   HP5plus.png   Tri-X.png  
    Using film since before it was hip.


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