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  1. #1
    Struan Gray's Avatar
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    Bromide Drag equivalent in C41?

    I send my 4x5 Portra to a lab for developing and am getting a persistent problem that looks like a light leak but doesn't make a lot of sense. I am beginning to wonder if the problem is with the lab.

    I am getting patches of odd colour and/or higher density around the corners of the film, especially on the top edge of the image. I use the Fuji Quickchange cartridges (NB: not Quickload) which other people have found leak prone, so at first I suspected them, but consider the following:

    1. E6 film in the same holders shows no patches.

    2. B+W film in the same holders shows no such patches. I also have B+W and colour neg pairs taken at the same time, in the same light, with the same lens. The colour neg has the patches, the B+W not.

    3. No patches on a sheet that was exposed to the inside of the camera but the shutter left closed. I.E. the sheet was unexposed, but was open to any light leaks.

    4. Patches on a sheet that was exposed to ambient light outside the camera for a couple of minutes. A very dense sheet, but there are still patches of odd-density at the corners.

    5. The patches are clearest on shots with high density near the corners: i.e. skies or snow. Dark areas do not seem to be affected as much.

    6. The odd patches are always 3-4 mm in size and form a lozenge shape around the clip holes from processing.


    I am reluctant to blame my processor for a fault that may be mine, but it is beginning to look to me as if development byproducts are being retained by the clips used to hold the sheet while processing. These are thenaccellerating development.

    Is this a reasonable thing to suspect, and can it happen in a dip-and-dunk C41 processing line? In B+W I would suspect insufficient or too-unidirectional agitation, but I am very much a paint-by-numbers person when it comes to colour processing so before I start complaining to the lab I would appreciate comments from people here.

  2. #2

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    Definately sounds like cross contamination to me. I get something similar with the Nova sometimes when doing RA4 processing. Its usually caused by a very small ammount of BLIX left on the clip if I havent washed and dried the clip properly. When I clip on some undeveloped paper some contaminates the paper around the clip before it is washed off in the dev. Personally I would be tempted to buy a Jobo and dev the film myself.

  3. #3
    Struan Gray's Avatar
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    Thanks LA. Glad I'm not just clutching at straws.

    I do have a Jobo CPE and am idly following auctions for 4x5 reels on eBay, but it's hard for me to have a darkroom in our home at present.

    The lab is Peak Imaging. They have always done such good work for me with other formats, and with B+W and E6 in 4x5, that I am reluctant to send too hefty a brickbat their way, especially since I'm not 100% sure that the fault is theirs.

  4. #4

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    Well, if the lab manager has an bit of good sense, they will thank you for bringing it to their attention, PROVIDED you do it with a good attitude and a genuine desire to find and correct the problem regardless of WHOEVER'S (whomever's?) fault it might be.

    Save the brickbat for the eventuality that they do not respond or dismiss your problems out of hand.

    My 2 cents...

  5. #5
    Struan Gray's Avatar
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    Never fear. I'm instinctively a more-in-sorrow-than-in-anger sort of person anyway.

  6. #6
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    Struan;

    C41 films contain high iodide emulsions with DIR couplers. This combination could end up with a film sensitive to a 'bromide drag' effect where the effect is due to iodide and the DIR 'fragment' which inhibits image development and causes edge and interimage effects.

    This would take place with improper agitation, bad replenishment, or mixed Kodak - Fuji products in one process (or mixed products of one mfgr of different types which are highly unbalanced in type).

    It is not unusual to see this. We were very careful at EK to make sure that the cross product 'contaminaton effect' was minimal, as we tried to balance halide and DIR effects across films, but with todays UC and VC films this is probably much more difficult to achieve.

    I would say that you should bring this to the attention of your lab and show them some of your negatives. BTW, E6 is also prone to this type of effect under the right 'wrong' conditions.

    PE

  7. #7
    Struan Gray's Avatar
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    Thank you PE. I'm afraid I don't know what "DIR" stands for: is it the remains of the sensitiser dye, or one of the bits that are left over once the colour dyes have been formed?

    I have read that saturated films can use a trick where development of one colour releases reaction products that suppress development of the other layers. I would be interested to know how much such inter-layer effects are universal in colour films, and how prevelent they are in my preferred low-contrast films. If you're allowed to tell us of course :-)

    These patches definitely require the area near the clip marks to have been exposed. I have a pair of negatives of the same scene, one taken with a badly adjusted compendium shade, and one with the shade correctly positioned. The vignetting by the shade has supressed the patches, despite the fact that it is not extensive enough to cover the entire patches had there been any.

    I will try and find time to scan one or two negatives so this can sit in the archives. I am also interested in hearing more experiences from anyone who has seen anything similar.

  8. #8
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    Struan;

    DIR = Development Inhibitor Release.

    During development, a very strong inhibitor is released during color dye formation. This DIR fragment inhibits development causing either edge effects or interimage effects. One improves sharpness and the other can improve either grain or color quality.

    Either way, if it is incorrect, it can look like bromide drag of a sort, causing streaks or blemishes in the image as you describe. Very often, the fragment released is similar to pheny mercapto tetrazole (PMT), a common antifoggant.

    PE

  9. #9

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    Does the DIR get effected by a pre-wash?

  10. #10
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    DIR couplers are not affected by a prewash in any way.

    PE

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