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  1. #1

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    Issues with exposures in bright light

    Hi all,

    I occasionally have annoying issued with exposures with my Chamonix as in this frame:



    This is a negative scan with an Arcus 1200. I am not good at scanning negatives but I hope it serves the purpose.

    Details: Cham. 45N-1, f9/360mm Apo-Ronar, HP5+ EI400, D76 1+1 9'30" rotation. Jobo CPE2, Multitank 2553, frameholder is the one with the wings to clip in after loading. The tank was filled with 560ml. There were six frames in the holder two of them have these stripes. The other one is the same scene but taken with a f5.6/150mm Sironar-N. The stripes on this are less obvious. I don't know where these two frames were loaded but it is very likely that they were in opposite positions in the frameholder.
    What is obvious for me is, that the stripes are very regular. So to me issues with pouring in or out the developer seem very unlikely.

    Has anybody seen something like this and can explain it to me?
    I always make to exposures of the same scene. So I can repeat the development. If this is an issue in the process I'd much like to know how to avoid it.

    Ulrich

  2. #2
    Anscojohn's Avatar
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    Do you think it is an exposure problem unrelated to bright light exposure or a problem with the roto processing? My guess would be with the roto processing?
    John, Mount Vernon, Virginia USA

  3. #3
    Ian Grant's Avatar
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    It's nought to do with the exposure, it's a process problem.

    Can't help furtheras all my tanks are inversion type

    Ian

  4. #4

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    I don't know. The stripes are orthogonal to the direction of rotation. I can not think of anything producing such regular stripes. With a focal plane shutter I would think of banding but it was taken with a between the lens shutter. I really don't know. But if anyone knows the reason, I'd much like to know it before I process the backups if it is related to the developing process.

    Ulrich

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    Ian Grant's Avatar
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    had to look up "Orthogonal" and the meaning was interesting "Not pertinent to the matter under consideration"

    Actually it looks as though the reel with the sheets of film isn't rotating properly causing the banding, could be slipping.

    Ian

  6. #6
    Sirius Glass's Avatar
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    Quote Originally Posted by Anscojohn View Post
    Do you think it is an exposure problem unrelated to bright light exposure or a problem with the roto processing? My guess would be with the roto processing?

    My thoughts too.

    Steve
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  7. #7

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    Quote Originally Posted by Ian Grant View Post
    had to look up "Orthogonal" and the meaning was interesting "Not pertinent to the matter under consideration"
    As you can see, my knowledge of the English language is improving
    Actually it looks as though the reel with the sheets of film isn't rotating properly causing the banding, could be slipping.

    Ian
    Thanks, this is the most convincing approach so far. I just looked into this. The foot of the middle tube and the counterpart in the tank have notches thus that the spool is fixed. There are two ways to put the spool in. In one position there is a slip of about 20° in the other the slip is about 5° to 10°.
    The tank itself is coupled to the CPE2 by a magnet. This may be another cause of slip if the rollers are causing so much friction that the tank has a slight slack as the direction of the rotation changes. This may cause irregular development square (!) to the direction of rotation. What I can not see is the cause of the very regular recurrence of the stripes.

    Ulrich

  8. #8

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    Six sheets in a 2509 reel can sometimes be two sheets too many if your film base isn't stiff enough to prevent the sheets from touching when wet. Were they stuck together when you pulled them out? One to the inside+ middle slot empty+ one to the outside might cure this.

  9. #9

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    Quote Originally Posted by Ulrich Drolshagen View Post
    As you can see, my knowledge of the English language is improving
    I love that word and use it often. But, then again, 4 out of 5 statisticians do also!

  10. #10

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    If you are using the slow speed, try it on fast, which is Jobo's current recommendation.

    That took care of the uneveness problems I was having, but I didn't get patterns extending across the whole neg. as you've shown.

    If you don't mind using around a liter of chemistry, you could try a few sheets using inversion.

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