E6 Tetenal 3 bath and slight magenta cast

Discussion in 'Color: Film, Paper, and Chemistry' started by Roberto, Jun 15, 2014.

  1. Roberto

    Roberto Member

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    Hello,
    I am using the Tetenal E6 Colortech 3 bath kit in a CPP2 Jobo processor.
    While the process is consistent and allows me to get the same results all the time, my Velvia RVP and RVP50 slides always get a slight magenta cast.
    Any suggestion about what the reason may be?
    Thanks!
     
  2. Muihlinn

    Muihlinn Member

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    Depending where you see the cast the fix varies, but I'd bet you can get the rid of it extending the wash before blix and the blix itself
     
  3. Rudeofus

    Rudeofus Subscriber

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    There are two kinds of magenta cast, one that is proportional to density, and one that shows up as extra magenta density. The first case would show clear, neutral highlights and indicate that the developer is off, while the latter one would show a strong color cast in the highlights and would suggest that your BLIXing and/or washing is incomplete.
     
  4. Roberto

    Roberto Member

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    I was thinking at the temperature of the color developer bath. In one case where the temperature of the whole process was accidentaly too low, I got a green cast.
    it is possible that an excess of temperature of 1°C can bring such magenta dominant?
     
  5. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Overdevelopment is one potential cause. Also, if the film is expired, it tends toward magenta, and you might find that pulling it can reduce that effect, but at the expense of contrast.

    I haven't used Tetenal 3-bath for some time, but as I recall, there were recommendations about adjusting the pH as well to address this sort of issue.
     
  6. Muihlinn

    Muihlinn Member

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    My bet is that as he said slight he's seeing it in highlights mainly, so it will be fixed with a longer wash of color developer and a longer blix as well. If the cast is clear in the shadows with some blue then it's low alkalinity in the color developer
     
  7. JaZ99

    JaZ99 Member

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    I'm facing similar problem. I do wash accordingly to the Tetenal instructions. Any tips?
    F0263.jpg
     
  8. Roberto

    Roberto Member

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    I improved the situation by:
    1. Using chemical strictly one-shot
    2. extending blix time a little bit (probably useless due to using fresh bath every time)
    3. Using faucet water which has more neutral ph than demineralized

    Still there is this tendency but very very slight . I can live with that. Should I want to be fastidious I could intervene on CD bath PH , but again, now that I work one-shot I am very satisfied with the results and don't want to mess with phmeters and other dangerous chemicals. :smile:
     
  9. JaZ99

    JaZ99 Member

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    Since I've acquired control strips, I tested batch re-using up to 4 times. My control strips are very much alike, regardless of which run they were developed in. It gives me great savings on chemistry ;-)
    I will try to double wash time and see what happens.
     
  10. JaZ99

    JaZ99 Member

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    I did the test. I have extended the washing time between CD and BX to 4 minutes (8 water changes). No improvement.
    Patch #2 is quite similar to previous one (from the fresh batch of chemistry) - it was 5th re-use, just for this test (jobo 2520 tank).

    T20140815-strip.jpg
     
  11. Rudeofus

    Rudeofus Subscriber

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    According to Tetenal's instructions you need to fine tune the pH of your color developer. Given the very high pH of E6 color developer, you can use Acetic Acid instead of Sulfuric Acid, but you can not use Sodium Carbonate instead of the Hydroxide, and you have to use moderately fresh NaOH solution while you are at it.
     
  12. JaZ99

    JaZ99 Member

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    Oh, yes, I'm familiar with this little strange booklet. I do correct pH of CD with NaOH, so my slides looks good on the light table. But I estimated the correction on the trial and error basis, and I want more scientific approach, so I bought control strips. The strips looks bad, the slides looks good. I'm perplexed.

    Are you sure? I have a tons of lab grade acetic acid I could use.

    BTW, sometimes accidents happen:

    [​IMG]
     
  13. Rudeofus

    Rudeofus Subscriber

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    Over the years I must have made almost any processing error you can possibly think of, yet most of my slides look ok. These control strips are brutal.

    Acetic Acid behaves very much like an acid at pH above 5-6, it has no impact on chemical reactions in color developer (except for the pH change it causes), and it does not form any precipitates, so it will most definitely work with a liquid that has a target pH around 12 ...
     
  14. JaZ99

    JaZ99 Member

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    Thanks for the tip!