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  1. #1

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    Is it possible to assess E6 first Dev condition by ph?

    Hi,
    I've been having unreliable results with my home E6 processing, and part of this is to do with the fact that I don't use it regularly enough to exhaust a batch within its 4 week lifespan all the time. But I was wondering whether it is possible to assess the efficiency of the 1st dev with litmus paper, rather than doing a clip test (I shot a 35mm roll of a kodak colour chart, but this still takes 20 minutes to make a rough assessment)?
    I would assume that each increase in time is due to a loss in ph, and that oxidation over time would also have this effect. It would be damn handy if it were possible to check its condition more simply.

    Thanks,
    Tobias

  2. #2

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    I ought to specify that this is the Fuji Hunt 3E6 kit and in a Jobo CPE-2.

  3. #3
    mts
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    Anyone doing color processing should have a pH meter. Litmus paper is not a satisfactory alternative. Measuring pH can certainly show that a solution is bad (out of range) but it does not prove that a developer is good. pH is measures necessary alkalinity but not the activity of the developing agent. You can get a rough idea of activity by developing a small piece of exposed film in room light. Obviously the film should process to black, then bleach completely, be re-exposed, and clear in the fixer (with appropriate washes and stops in between). If developer activity is verified, the quality of the processing can only be evaluated by processing test strips.
    By denying the facts, any paradox can be sustained--Galileo

  4. #4

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    If this is the case, then why is it that I cannot find any data on the correct ph of E6 first dev? I would have thought it would be something published in the manuals to the chemis, so that one can verify whether the local water is affecting the solution, however i have found nothing.

    Also, with the market flooded with cheap chinese equipment, litmus may be as effective if not more precise than a meter. Today I am challenged with having just got a new digital thermometer, and wondering whether the Jobo thermometer is more or less correct than the electronic one, as it tells me that my CPE is at 38c, the digital says 36.8c.

  5. #5
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    It is in the E6 control handbook published by both Kodak and Fuji-Hunt. They charge for the book!

    IDK the value, but it is about 9.5 and that is just "close".

    Litmus is NOT as accurate as a pH meter, and as MTS says above it does not tell the whole story!

    PE

  6. #6
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    Sorry for my silly question, but I do like the idea with the exposed film strip. Did I get this right? I'd should just clip off a piece of film when putting it on the spool, then completely expose it in day light, then watch in broad daylight whether the developer turns it black. This doesn't even involve expensive measurement equipment, and one could write down times when the dev batch is fresh and keep track of the times as the batch gets older. I like it, I like it ....
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #7
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    That really only works with B&W film. With color it is more difficult to assess.

    PE

  8. #8
    mts
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    Your thermometers can easily lead you astray. I use a glass Kodak color thermometer as the reference for the dial thermometer that I use most of the time. Get two of the glass thermometers and compare them against each other keeping one in reserve for when you manage to break one--it is all too easy to do. Dial thermometers are almost always adjustable usually with a nut that is behind the dial. Digital thermometers may or may not read correctly depending on the complexity of the circuitry and the thermocouple or thermistor that is used. I like to think that using glass Kodak color thermometers maintains the analog tradition!

    Your time/temperature is most critical for the two developers. The first developer time controls film speed more than anything else while its temperature and activity level ensures that the layers process to their proper characteristic curves, viz. there is no cross-over. The color developer creates the layer dyes and its activity and temperature must be correct to achieve proper color saturation and balance. A quality pH meter will be temperature compensated and will usually indicate temperature as well as pH. Measuring pH to .1 unit is satisfactory in practice but .01 is preferable.



    The bleach, fix, and stabilizer and intermediate washes need not be timed so accurately and their temperature is important only to prevent thermal shock to the film. A few degrees off for these baths is not important, but the bleach and fix must operate to completion. For that reason I prefer to process these baths in room light with inspection to verify that they complete. Obviously, you can also perform the color developer in room light. The only solutions that must be processed in darkness or in the tank are the first developer and the first stop bath.

    Do not make the mistake of interchanging the first and second stop bath!

    PS: can you really call your photography analog if you use digital timers and thermometers? Well, maybe I should make allowance for a digital pH meter because analog ones are hard to find these days.
    By denying the facts, any paradox can be sustained--Galileo

  9. #9

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    Anyone have experience with the cheap pH meters they are selling on Ebay or can recommend one that I might find used that is not too costly?

  10. #10
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    I use one by omega. It was found locally at a Hydroponic grow shop.

    It is not thermally compensated, but a conversion table from the web pasted to the storage box solves that annoyance.

    I keep the probe in fresh KCl after every use and the thing is still viable after 5 years, which surprises me, because I thought I would only get a year or two out of it.

    It does eat batteries even when off, so I take the batteries out between uses.

    It cost about $160Can and is still working when I call on it, like when I DIY mix my colour chems.
    my real name, imagine that.

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