extending c41 times

Discussion in 'Color: Film, Paper, and Chemistry' started by wilfbiffherb, Dec 3, 2011.

  1. wilfbiffherb

    wilfbiffherb Member

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    Hi,

    I have been developing a few rolls of c41 ektar and portra over the past few weeks using a jobo cpe2 with 250ml of solution and rollei digibase chemicals.my first 3 rolls came out well but my fourth is a bit dense and slightly fogged in areas, it looks potentially undeer bleached even though. I did it for the same times as my previous rolls. My question is should I be extending my dev,bleach anf fix times for each roll I develop at all?
     
  2. 2F/2F

    2F/2F Member

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    Hi,

    You should not need to extend your development time unless you are reusing your developer. And you should not do that in a JOBO anyhow, as all the swishing about oxidizes the developer faster than with hand inversion in a full Nikkor tank.

    The rest of the chems should be fine to reuse in a JOBO.

    I notice that you shoot plastic cameras. Could it simply be caused by a light leak?
     
  3. wilfbiffherb

    wilfbiffherb Member

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    I used a bronica sqa on these rolls so they should be light tight. Hmm,never thought about using the dev as one shot. That would be ridiculously expensive surely!!
     
  4. 2F/2F

    2F/2F Member

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    Especially with the heavily priced Rollei chems. Kodak bulk chemicals are by far the more cost effective way to go if you are using a JOBO.
     
  5. Rudeofus

    Rudeofus Subscriber

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    The user manual for the Rollei chems states detailed instructions for Jobo 25xx tanks and rotary processing, so I'd assume they are supposed to work together. One thing that surprises me is that the Rollei manual mentions no soup time increases with reused chems, especially since Tetenal specifies quite hefty soup time increases for their chems (which are different but anyway).

    If you leave dev time the same, you should get thinner negs after multiple uses, not denser negs, so I assume that your dev is not the culprit here. Excessive density plus base fog points a lot more towards insufficient bleaching, and fortunately that is a step you can redo. If you are up to a little experimenting, I'd do the bleach, fix and stab steps over again (with the chems you already have) and look if your negs suddenly turn out nice. Depending on how much you trust your chems you could consider using fresh bleach soup for this.
     
  6. wilfbiffherb

    wilfbiffherb Member

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    Yeah I may give that a try. Or just do my next roll with a 30sec longer bleach time and see how that comes out. I love the rollei instructions-no washes included at all!!
     
  7. Rudeofus

    Rudeofus Subscriber

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    Remember, the bleach and all following steps can be done in broad daylight, so you can even watch whether the bleach does its work.
     
  8. pentaxuser

    pentaxuser Subscriber

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    What bleach time are you using? The digibase instructions say 3-4 mins but looking at the 30+ page thread on Digibase the suggestions seem to point to 6 mins 30 secs.

    From what I have understood you should err on the long side


    pentaxuser
     
  9. 2F/2F

    2F/2F Member

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    There is absolutely no reason they wouldn't "work together," but the developer should only be used one shot in a JOBO. This is due to all the air in the tank during processing, and the constant agitation, causing more oxidation than in hand processing in a full tank, agitating intermittently.
     
  10. jbl

    jbl Member

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    I've been developing rolls with the Rollei chemistry and feel like I'm not getting enough negative density. Things look okay, but since I'm going to a scanned workflow, I'm judging negative density based on what comes out in the scan. Rolls consistently seem to need brightness enhanced on the computer. The shadow detail seems fine, so I don't think it's underexposure (at least not across the board). I've seen the same behavior with fresh chemistry and reused chemistry. In b&w, I'd either increase exposure or increase development time. Do the same principles apply with color?

    -jbl
     
  11. Rudeofus

    Rudeofus Subscriber

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    The pricing and sizing of the Rollei chemistry is such that no one in his right mind would consider using it as single shot chemistry. If, therefore, the (otherwise sparse) manual explicitly states mixing instructions for rotary processing including estimates for number of reuses, then Rollei (or Fuji, who makes the stuff anyway) must think that their chems can be used multiple times in rotary processing. Some folks on APUG also seem to think that this works. Don't forget that you mix very small quantities of soup for rotary processing, so you don't reuse the chem all that much anyway.

    jbl, you judge your results by what you get from your scanner ... please remember that you scanner most likely makes some auto level adjust, which may or may not deliver the image brightness you want, completely independent of your neg density. There is a reason the pros do density measurements.
     
  12. hrst

    hrst Member

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    You CAN reuse C-41 even with rotary Jobo. It is true that there is a bit more oxidation than with manual agitation, but the oxidation that happens during the 3 minutes is still comparably low.

    I have never seen any official statement that you couldn't do that, and I have had absolutely no problems. If this is an official instruction, please state a source.

    However, usually there is no need for reuse, or for more than one reuse; with Jobo, the volume of chemicals is so low that you reach the specified life of the chemicals anyway. Also, if you don't develop very much, it's good to "go through" your chemistry so that it doesn't go bad. To be on a safe side, in a month.

    One-shot is a sure way, it also protects from dilution (if you use a prewet) and contamination. However, one reuse is not that much. I have reused as much as three or four times (increasing the developer time as instructed), exceeding the stated capacity manyfolds, with good results; C-41 is a robust process with built-in safety factors so you don't need to add your own. Just don't reuse more than once in a Jobo because then you are going to exceed the specified capacity anyway.

    If you reuse bleach many times, use a half-full bottle and give it a few good shakes to regenerate it by oxidation. Also, bleach for 6'30, preferably around the process temperature; it may be a bit too slow in room temp.

    Keep also in mind that the fixer has a limited capacity, too; probably shorter than the bleach.

    Also, YOU HAVE TO WASH between bleach and fix. There is a crucial error in Digibase instructions. This can cause increased density and a color cast. AFAIK, it is not correctable afterwards.