Film Holder Wierdness...

Discussion in 'Large Format Cameras and Accessories' started by Ian Leake, Jul 4, 2005.

  1. Ian Leake

    Ian Leake Subscriber

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    The attached scans show a pair of symmetrical artifacts I found on a recent negative. There are two blurred dark lines perpendicular to the long edges towards the right hand end of the scan.

    Presumably if they were light leaks then they would be bright not dark, so I assume that they must be something else.

    The film was in a standard Toyo 5x4 film holder. Other shots with different holders on the same day didn't have this so I presume the problem lies with the holder not the camera. I haven't used this holder since, although I plan to run some tests when I get the chance. However I have done a physical check and can't see an obvious cause.

    Has anyone seen anything like this before, or can you suggest what I should investigate? The only thing I can think of is that I may have bent the film as I slid it in or out of the holder. Could this be it?
     

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  2. Mongo

    Mongo Member

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    The first thought that comes to my mind is that it's something with the film, not the holder. These aren't light leaks. Does the film look buckled at all where the line is? (Hold the film at an angle to a light and move it around; you should be able to see any deformation to the film base.) This could have been caused by buckling during loading or processing, or by a manufacturing problem. If it was one of the first two, you should be able to see a problem with the film base. If it's the third then examination under a magnifying glass should reveal an irregularity in the emulsion itself. The only other thing I can think of would be a problem inserting the dark slide, but I'd have expected that to leave a bright mark on the print rather than a dark mark.

    Check to see if the film's been buckled. If not, I'd say shoot another sheet as soon as possible in the holder. I can't be certain, but I'm pretty sure you'll find it wasn't the holder.

    Good luck.
    Dave
     
  3. Ian Grant

    Ian Grant Subscriber

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    What's odder still is it's on both sides of the film, so not the film holder, or rather highly unlikely unless you have a hair or other unwanted bits in the holder/

    Perhaps it happened during loading or processing. You dont say how you process the films.

    Ian
     
  4. lee

    lee Member

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    I might be tempted to just develop a sheet of film that has not been in the holder and see if it is "pre-exposed" film

    lee\c
     
  5. Mongo

    Mongo Member

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    Pre-exposure would leave a dark mark on the film, and a light mark on the positive. What you're seeing here is either missing emulsion, deformed emulsion, or a deformed film base. (The latter two might cause the light to be deflected, leaving a dark spot during printing. The first would simply allow light through, leaving a dark mark.) Since it's dark on the print, it isn't a light leak or any other type of light strike.

    Beats me as to what it is, though. Developing an unexposed sheet from the same box would show if the same defect appears. You said you shot film in other holders the same day, but not whether the film came from the same box.

    Let us know what you see when you look at the negative.

    Be well.
    Dave
     
  6. j_landecker

    j_landecker Member

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    How was the film developed? Contact with the triangular stand-offs in the grooves of Jobo 2509 reels can sometimes prevent development at the contact point, and you don't see it in other areas of the negative, because that's where the clear border is.
     
  7. Ian Leake

    Ian Leake Subscriber

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    Solved (I think)

    Thanks everyone for your thoughts on this. I can't see any damage to the film base, but when I look at reflected light glancing off the emulsion side I see two shiny patches. So the emulsion is damaged.

    I think Jim hit the nail on the head: I developed this in a Jobo 2509 reel. If I place the film in the innermost groove with emulsion side outwards, two of the triangular spacers rest just where the marks are. So I think I must have put the sheet into the reel the wrong way round.

    It's feels better to know it was user error rather than an equipment failure.

    Again, thanks everyone for your help.
     
  8. j_landecker

    j_landecker Member

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    Glad the mystery is solved... When I used to use those reels (using Expert drums now) I would get those marks with the film correctly inserted too, but they never bothered me because they got cropped out during enlarging. What process are you using to make those prints?

    Jim