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  1. #31

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    IR black spots on negs

    Quote Originally Posted by eddie gunks View Post
    thanks so far. the spots show up more on certain frames. maybe the pressure plate is to blame. i am shooting HIE 35mm. what could i use on my pressure plate? now i am beginning to worry about solving this problem. i never thought about the pressure plate! damn! i am shooting an N90S.

    eddie
    I read recently (can't remember where) that there can be a problem with air bubbles during development. The remedy is to pre-wash with water or bang the heck out of the developing tank after adding the developer.

  2. #32
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    Maybe, maybe not

    Quote Originally Posted by Chris Usher View Post
    I read recently (can't remember where) that there can be a problem with air bubbles during development. The remedy is to pre-wash with water or bang the heck out of the developing tank after adding the developer.

    I've heard this one too and decided to test it: Tried a pre-soak w Photoflo, made no difference whatsoever (still got the same pinholes).

    I always firmly tap the tank during the first couple of agitations when developing (including those rolls which showed pinholes).

    It hasn't come up in this thread yet but in case it does I tried using a water stop bath instead of acid, again, made no difference whatsoever (using D76, which, Kodak told me, contains no carbonate to make CO2 gas with acid to make pinholes).

  3. #33

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    thanks guys! it looks to have been the film. a shot from my tset roll.

    eddie
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  4. #34
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    Quote Originally Posted by eddie gunks View Post
    thanks guys! it looks to have been the film. a shot from my tset roll.

    eddie
    So I take it this was non-expired ilm, cold stored until exposure and processed shortly after exposure?
    Good luck with the wedding shoot, hope everyone likes the IR work.

  5. #35
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    Quote Originally Posted by DaveOttawa View Post
    Sorry old bean but none of the above seems to apply at all to the OP's stated and shown (see scans) problem. He is observing black spots on prints/white spots (holes, lack of density) on the neg emulsion, you are talking about various effects which would lead to extra density on the neg.
    There's no reason to expect the chemistry of a high energy impact with ionizing radiation to be anything like your usual picture of a electron meekly migrating to a sensitivity site while a hole is trapped. The effect I imagine would be more like obliterating a sensitivity site or a whole group of adjacent sites, the net effect perhaps more akin to solarization. And there are plenty of related two-event phenomena to consider i.e. the Herschel and Debot effects.

    I don't know whether my theory about these films is correct, but it's not as easy to dismiss as you imply. From what I have read on the subject (including some of the links mentioned above), there is no systematic study, merely conjecture.

    Anyway it sounds like a simple solution was found- don't use old film, and develop reasonably quickly, which is what Kodak clearly recommended in the first place.
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  6. #36
    Robert Hall's Avatar
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    Yes, I have seen this on several IR HIE films and while we have never pinpointed the pinholes, we certainly have seen them.

    With several calls to Kodak we have not gotten a credible response from them as to the cause.

    Many blamed the stop bath being to acidic, but this is shear speculation and anecdotal with no supporting evidence.

    Much of this went away with the new machines making the HIE in rolls and not making it in sheet anymore. (sigh)

    But I know several people with 4x5 sheet film in the deep freeze who don't want to sell it and don't want to use it for fear of the pin holes.

    This pin hole discussion, BTW, has been going on for 5 years now.
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  7. #37
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    Quote Originally Posted by keithwms View Post
    There's no reason to expect the chemistry of a high energy impact with ionizing radiation to be anything like your usual picture of a electron meekly migrating to a sensitivity site while a hole is trapped. The effect I imagine would be more like obliterating a sensitivity site or a whole group of adjacent sites, the net effect perhaps more akin to solarization. And there are plenty of related two-event phenomena to consider i.e. the Herschel and Debot effects.

    I don't know whether my theory about these films is correct, but it's not as easy to dismiss as you imply. From what I have read on the subject (including some of the links mentioned above), there is no systematic study, merely conjecture.

    Anyway it sounds like a simple solution was found- don't use old film, and develop reasonably quickly, which is what Kodak clearly recommended in the first place.
    My point was simply that all the influences you cite (essentially ionising radiation or visible electric discharges - i.e. sparks) will cause density to increase in the neg: the OP had a problem with lack of density.
    I'd agree there is no readily findable systematic study of the "pinhole in HIE effect", but there are a number of empirical observations that suggest storage history of the film is the strongest factor.

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