X-ray film---some sheets fogged, others fine. What happened?

Discussion in 'B&W: Film, Paper, Chemistry' started by ntenny, Jun 30, 2013.

  1. ntenny

    ntenny Member

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    So I've jumped on the X-ray film bandwagon, as a cheap way of shooting 8x10 and for the "why the hell not" value. I ordered a single box of 100 sheets (Kodak, green-sensitive, from Z&Z Medical).

    Last week, I exposed two sheets of it and all was well. I happened to pull them from the middle of the stack; I loaded them in the dark, then realized they were safelight-safe and developed them by inspection under a safelight. Since then, the box has been sitting closed in a normally lit room.

    Today, I exposed two more sheets; this time I took them from one end of the stack and loaded them under the safelight, but otherwise everything was the same. They developed to uniform black; no filmholder edges. So I took another sheet (again from one end of the stack, though I'm not sure it was the same end) and developed it without loading or exposing; it developed clear (and I confirmed afterwards that the developer was still capable of blackening film).

    Those are the facts as we know them. I'm trying to figure out what happened and whether I can trust the rest of this box of film!

    Some inferences and speculations follow, but any of these could be wrong.

    First of all, since there are no filmholder marks, the fogging happened either before loading or after unloading. After unloading, there were no differences in handling between the good and bad sheets, so they were probably fogged by the time they went in the holders.

    That *could* have been from storage in a light room, but it seems odd that there would be complete fogging of two sheets and nothing on the rest; I'd expect fog at one end of everything, since the bag inside the box opens at the end, and an uneven pattern that indicated where the light was getting in.

    It shouldn't be from loading under the safelight, since the same safelight hasn't caused any problems for the last test sheet or during development.

    If those inferences are right, the conclusion would be that the factory-sealed box came to me with two sheets already fogged. But that seems ridiculous; how on earth would that happen?

    Any thoughts? Is this something other people have seen?

    Thanks

    -NT
     
  2. johnielvis

    johnielvis Member

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    well, you may want to just pull a sheet from the box and develop it first--see if the film in the box was messed before you go speculating.

    if the boxed film is not messed, then you obviously have loading/unloading problems--or you could have pulled the wrong dark slides or something.
     
  3. 3 Olives

    3 Olives Member

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    The chances of having totally exposed film with unexposed film are petty slim. If you loaded and unloaded the film the same way there shouldn't be fog. If so, I imagine light must have fogged the film after loading and before unloading in the darkroom. Are the cassettes you loaded the film into tight or is there room for light to travel along the edges?
     
  4. ntenny

    ntenny Member

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    I have no explanation, but it looks like only those two sheets were at issue. After the one test sheet already mentioned, I did two more---one from each end of the stack---and they developed clear, so I took two more out and actually shot them, and the resulting negatives look perfectly normal.

    Try as I might, I can't think of any way that I could have gotten two entire sheets uniformly fogged in a known-good holder. (Even if I'd pulled the wrong darkslide twice in a row, and managed to put them both back with the correct orientation but without noticing anything was wrong, the holder edges would still be there.) I guess it's just possible that something mysterious happened in my darkroom, but I really do think the simplest explanation is that my box had two fogged sheets in it!

    Science is baffled, but I guess this is the end of the story. The best explanations I can think of are that it was X-rayed in the post and the film is radiopaque enough that it only affected two sheets, or that I happened to get the very tail (or head) of a bad production batch. But neither of those is all that plausible, and I don't really see any way to investigate further, so...*shrug*.

    -NT