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  1. #1
    PeterB's Avatar
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    I have artifacts outside my 120 film frames. Why?

    Hi folks,

    I have run at least 8 rolls of film through my Mamiya C330 MF camera and under certain conditions (perhaps slower shutter speeds, and or over exposed images) I get artifacts outside the square frame area on the negative.

    They are different in appearance, probably unrelated. Artifact 1 is a parallel line along each of the two frame edges parallel with the film edge, darker at the top of each frame. Artifact 2 is almost like halation spilling over the top edge of the frame.

    I'm attaching two photos showing these. The 2nd attachment with orange text on it is a close-up of the 1st with the contrast increased to better show artifact 2.

    Click image for larger version. 

Name:	IMAG0391_HP5plus_120_image_border_artifacts.jpg 
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ID:	37465 Click image for larger version. 

Name:	IMAG0392_HP5plus_120_image_border_artifacts.jpg 
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ID:	37466

    Anybody with any ideas ?

    thanks
    Peter

  2. #2
    zsas's Avatar
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    Could it be that the pressure plate is not holding the film a 100% flat and some light gets above the edges and flashes it a little?

  3. #3
    PeterB's Avatar
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    Nice idea zsas. I'll check that out in a few hours.

  4. #4
    markbarendt's Avatar
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    I have had something similar in two cases with my RB.

    1 when it needed new foam.

    2 with my 150SF lens. In this case the effect was softer than what your examples show.
    Mark Barendt, Ignacio, CO

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

  5. #5
    PeterB's Avatar
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    Neither foam seals nor pressure plate.

    Thanks Mark. I'm unsure what to test for if the lens is faulty.

    I have replaced all foam seals surrounding the door at least 6 months ago. They are as good as new.
    I inspected the pressure plate and it appears to be working OK. Its springs compress about 1.5mm when closing the lid. There appears to be even pressure along the two outer rails. Placing ink on pressure plate and closing lid transfers ink to a piece of paper which wasn't quite wide enough so I moved it across and closed lid a 2nd time.

    see photos.

    Click image for larger version. 

Name:	IMAG0399_inside my Mamiya C330. outer rails higher than inner 120 film rails.jpg 
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ID:	37472

    Click image for larger version. 

Name:	IMAG0397_pressure plate deposits ink onto outer rails.jpg 
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  6. #6

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    Perhaps you should take a roll at only fast shutter speeds and one at only slow shutter speeds and develop both in the same tank at the same time to rule out or rule in a shutter problem.

    http://www.jeffreyglasser.com/

  7. #7
    PeterB's Avatar
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    What possible failure mechanisms of the shutter could cause the artefacts I showed in my 1st post ?

  8. #8
    ic-racer's Avatar
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    The image opening does not actually touch the film, the film rail does. You are seeing the effects of light get between the image opening of the camera eventually being stopped by the film rail. This is normal for that camera.

  9. #9
    PeterB's Avatar
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    ic-racer, your explanation makes perfect sense. So this is the normal behaviour for this and most likely other MF cameras?

  10. #10

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    The OP said that the artifacts are outside of each of the negative frames so it cannot be a shutter problem. I would suspect a light leak. These cameras have a removeable lens. Perhaps the lens is not making good coontact with the camera body. Since the problem is intermittent perhaps like many small light leaks it only happens in strong sunlight.
    Last edited by Gerald C Koch; 07-29-2011 at 09:56 AM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

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