another rb67 back problem

Discussion in 'Medium Format Cameras and Accessories' started by nwilkins, Mar 3, 2013.

  1. nwilkins

    nwilkins Member

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    I have two RB67 Pro S backs, and one of them is working fine. The other is producing a thin line on the film (across the bottom of the frame in landscape orientation, or left side in portrait). Has anyone ever seen this phenomenon before? It almost looks like a scanner artifact, but it is clearly present on the negatives themselves (and does not appear on films from the other back). Here is a crop of an image where it is noticeable:

    line crop.png

    Any ideas what is happening? Is something scratching the film?
     
  2. MattKing

    MattKing Subscriber

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    Has the image you posted been inverted to a positive, or are we looking at the negative itself?
     
  3. nwilkins

    nwilkins Member

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    no that is inverted to a positive. so in reality the line is clear on the negative. basically looks like a line where there is either no emulsion (a scratch?), or where the emulsion was not exposed to light (which seems unlikely, no?)
     
  4. polyglot

    polyglot Member

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    Look for something scratching the film, e.g. where the insert plugs into the frame of the back.
     
  5. nwilkins

    nwilkins Member

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    yes I shall do once I finish off the roll that is in there. This is the same back that has been having the trouble with the counter - thinking it might be time to look for a new one anyway.
     
  6. Alan Klein

    Alan Klein Member

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    I once had one of my wife's red hairs trapped across the film opening leaving a thin red line across every negative.

    It better not be one of hers!
     
  7. MattKing

    MattKing Subscriber

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    Sounds like something is intruding into the edge of the film gate, and therefore blocking the light.

    Is there a problem with the film gate, such as a loose piece of film from the dark slide channel?

    Is the back not mounting correctly to the rotating adapter?
     
  8. nwilkins

    nwilkins Member

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    thanks for the suggestions - I will look into these possibilities. it feels to me like scratching is the likely cause. If something is blocking the light it would have to be a very thin hair or thread, and this is unlikely since looking back the problem has been occurring for at least the last 10-20 rolls. I just haven't noticed it because it is virtually hidden unless the negative is very dense along that side, and also I usually crop to 4x5 so I don't pay much attention to the very edges of the long sides of the neg.
     
  9. snegron

    snegron Member

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    I had a similar issues with one of my backs. It also leaked light. I noticed that the foam was gummy and and some particles got caught in the track. You might want to get that back re-foamed/cleaned/repaired or you might risk ruining more film.