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  1. #11

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    Quote Originally Posted by Photo Engineer View Post
    You seem to have 3 different minimum densities there ... If we can explain that, maybe the two edge lines can become more understandable.
    Can you shed some light on this?
    That's a very acute observation.
    It had not occurred to me to consider it in this way, but I'm sorry to say I have no light to shed - hence my posting!

  2. #12
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    It looks like agitation problems to me. Quite apart from the 3 bands, there's a cirrus-like streaking effect across the middle of that unexposed frame that speaks of either chemistry contamination or weird fluid-flow issues during development.

    Are you doing inversions or the twirly-stick? How fast? How often? I would suggest testing in a commercial developer too in case your caffenol is causing problems.

    The QC problems with Foma related to scratching, not unevenness.

  3. #13

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    As far as agitation goes, if you read my initial post carefully, you will see that:
    Quote Originally Posted by pdeeh
    30 seconds initial inversions then 3x inversions at 60s intervals.
    But of course I did not specify that I use what I class as "gentle" inversions.

    As for use of a commercial developer goes, see my third post:

    Quote Originally Posted by pdeeh
    I've got another roll in camera at the moment and I'll try that with D76 when it's finished, which should rule in or out a developer issue.

  4. #14

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    How viscous is this caffenol stuff? The film certainly doesn't look even in the middle of the blank frame - and that should be a completely smooth tone. Possibly that central variation comes from the piece of paper (or whatever) which you were using behind the negs?

  5. #15

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    Martin, I can't guarantee that that was a completely unexposed frame, plus the negative was indeed photographed against a sheet of paper.
    I can't re-examine or re-photograph the negative on a lightbox as it is part of one of the strips I sent to Foma at their request.
    Viscosity: Not very - imagine a cup of coffee!

    in the meantime, I have another roll in my Fuji 645, and I have deliberately left an unexposed frame on that roll for comparison. It will go through D76 1:1 which should at least establish if it is a developer &/or technique problem, or an emulsion problem. I'm expecting the former rather than the latter.

  6. #16
    AgX
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    Maybe there are two independant causes. The higher density at the rebates could be light fogging during signing. The line of minimum density could be of a reel induced effect due to lesser development. It might even be covered somewhat by the higher rebate density. (Looking at scans at my labtop-screen is a bit tricky.)

    A processing with bare film, thus without reel, could yield more insight.

  7. #17

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    suspicion falls on the caffeine-fuelled culprit ...

    I've now run another roll through in D76 1:1, 8:30@20C, 30s inversions + 5s inversions every 30s. Same Paterson Universal Tank.

    As we can see from the attached negatives (shot on a lightbox with macro lens), the apparent uneven density is no longer apparent, and the "edge lines" are entirely absent.

    So, it looks like it was Caffenol what done it, in the kitchen, with the tank ...

    Pity, as I have had excellent results with Caffenol previously and found I prefer it to D76 (Caffenol's a bit "sharper" to my eye); however, this is the penalty of using non-standard developers. I still remain curious how such a uniform effect along the entire length of the rolls could have been formed in the first place.

    It'll still be interesting to see what Foma's engineers have to say, but I shall drop them a note anyway with this finding.
    Attached Thumbnails Attached Thumbnails 20130301_1038-21-1.jpg   20130301_1037-20-2.jpg  

  8. #18

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    The problem with Caffenol is that there is a fair list of films that do not really like it. Caffenol is still in the "alchemy" realm, meaning that no thorough scientific work has been published on it to date, and no company is backing it either. You are left to internet fora and own experimentation for information that is often contradictory and/or incomplete. Not that it is a reason not to use Caffenol, but you should do so with care, and for every new film be sure to test thoroughly. One thing to never do, is develop an important film roll in a developer previously untested for that film. That goes triply for Caffenol, because the guidelines are somewhat vague, to be honest, and much of the info is scattered all over the place instead of a comprehensive fact sheet. I made the mistake of developing TMax400 in Caffenol according to the general instructions, and overcooked it by at least two stops. It took me a while to find out that TMax400 is one of those films not to develop in Caffenol. In fact the inconsistency and unpredictability have put me off caffenol for a while. Not to mention the smell.

  9. #19

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    Yes, I researched Caffenol thoroughly before starting using it, and as I said, this sort of result is the penalty for using non-standard (by which I meant non-commercial) developers.
    So long as one goes into it with one's eyes open, and one doesn't expect perfect and consistent results across all films, it's good fun.

    I've stuck to Reinhold's blog for my source data, and the information he presents there is clear and consistent. There's certainly a lot of "just throwing in a spoonful of this and that" sort of information floating about elsewhere, which doesn't help the easily confused, of course. I'm quite surprised to find a problem with Fomapan 200 as many others are using it with Caffenol without problems. However, who knows what's in my coffee ?

    Another one to avoid with Caffenol is Rollei Retro 400S, by the way

    I have to say, I simply don't notice the smell as being any more noxious than other photochemicals, or indeed many household cleaners.

  10. #20
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    Caffenol is a bit "sharper" because it's not got much in way of silver solvents (sulfite). You can make D76 look more like that by using higher dilutions (and correspondingly longer times) to reduce the solvent effect. Or you can use Rodinal which has no solvent action at all.

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