pH Meter Suggestions

Discussion in 'B&W: Film, Paper, Chemistry' started by DarkroomExperimente, Nov 29, 2007.

  1. DarkroomExperimente

    DarkroomExperimente Member

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    I've been having a lot of fun experimenting with homemade developers.

    I think it's time for a bit more precision....so I'm considering getting a pH meter.

    Any suggestions of what type to get...and from where?
     
  2. Mike Wilde

    Mike Wilde Member

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    low budget option

    I bought an Oakton pH Testr1. It is not temperature compensated, but it can be corrected with a little table to figure what the reading is equal to at 20C. There is always a thermometer handy, and I live with the single point option, though temp compensation would be handy.

    It cost about $150 CAN two years ago. The down side is that it seems to consume power even when it is alleged to be turned off, so I now store it with the batteries off. It is watertight so if you drop it into the rinse water,etc, it is still ticking afterward.

    I store it with the element soaking in small beaker of 3N solution of Potassium Chloride. 3N is 3M into 1L of distilled water. The MW of KCl is 74, so 74g into 1L. I actually mix it 100mL at a time.

    It is a single point compensated unit; you feed it pH 4, 7 or 10 buffer solution and after it has been stewing for 30 seconds/blinks, you press confirm, and adjusts the display to be either 4.0, 7.0, or 10.0. Fancier units get fed two buffers, and set the zero offset and slope from these two measurements. The buffers are commercially available where the units are sold for about $5 per bottle, and the bottles go a long way; I pour a small amount, say 10mL into a childs medicine cup and calibrate on this amount.

    I bought it at a local hydroponic shop - ie storefront for the average dope grow-op guys. I bought it on a credit card, and they were tickled, because they had only recently got the credit card terminal, and I was the first customer to ask to use it. It seems that most of thier customers like to deal strickly in cash.
     
  3. DarkroomExperimente

    DarkroomExperimente Member

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    thanks....

    anyone have a preference between Hanna & Oakton pH Meters??
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    I have the Hanna meter. It fits in my pocket and is waterproof. The electrode guard is able to be wetted to keep the electrodes safely in buffer when stored. The batteries are my originals over 3 years old, and the meter gets MEGA usage as you might guess.

    Calibration is rock steady.

    PE
     
  5. john_s

    john_s Subscriber

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  6. Photo Engineer

    Photo Engineer Subscriber

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    Well John, for my over 30 years at Kodak, we used Beckmann pH meters for the most part with no special electrodes. I've used them for developers, fixes, blixes, bleaches and for stabilzers.

    I know what it says there, but for the most part a dip in a photo solution is not going to hurt you as long as you wash the electrodes well.

    As for measuring pH, vAg, pAg or the like in an emulsion, that is a different matter and the web page you reference does not address that at all in any way whatsoever.

    The only 'oddity' that I have run across in over 30 years of making pH measurements, is that we used a special micro electrode pair and a special surface electrode for measuring the pH of the emulsion during processing. Other than being micro and very fragile there was nothing unusual about it.

    Sorry. This comes from 'real' use in a research and development environment, not 'guesstimation' from reading a few books.

    PE
     
  7. Tom Hoskinson

    Tom Hoskinson Member

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    I also use a Hanna meter and have found it to be stable and reliable.
     
  8. DarkroomExperimente

    DarkroomExperimente Member

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    thanks PE....you just answered the question I was about to ask

    the Suzuki link was making me wonder how easy these things are to use
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    It is good, but is overstating the case, or is overcautions. IDK which and IDC.

    PE
     
  10. DarkroomExperimente

    DarkroomExperimente Member

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    of rinsing/washing something and taking care of it is all I need to know -- I'm happy

    ...I rinse stuff all the time anyway
     
  11. gainer

    gainer Subscriber

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    Things I should have learned in school but didn't.

    When you want to prepare a solution of a certain pH is it best to titrate with an indicator or a meter or some other means? How accurately should we know the pH of a developer solution. I have a feeling that test strips would be sufficient for most of our needs, but our wants are something else. I know that in research work one is often trying to determine the efect of changes in pH on something or the effect of changes in something on pH. One might like to know for example whether a production line has to use reagent grade of some ingredient or if a lower grade would suffice.

    From experience, I know that due to the logarithmic scales on most of our darkroom work there is a fair tolerance in the linear measures of weight and volume. How else could Crawley, for one, concoct a developer with measurements in nice round numbers and then proclaim it optimized for this or that? (I'm poking fun. Of course we know all his developers are optimized.)

    I'm always curious about pH and other quantitative measures of qualitative things, but it's always after I've seen that they work or not. Right now, I'd rather spend the money, if I had it, on a good shutter for my 5x7 camera.
     
  12. Fotohuis

    Fotohuis Member

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    I am using a Hanna too. It's an inherity of the previous job :D

    Just take care of the electrode (which is valid in general for pH meters) and then you have a pretty good instrument.
     
  13. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I'm also using the Hannah Checker, and it seems reliable.
     
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  15. Photo Engineer

    Photo Engineer Subscriber

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    Patrick;

    There are known formulas that will allow you to calculate the exact mixtures of carbonate to bicarbonate to get a given pH. You usually mix those in the right proportions and then add a few drops of acid or base with a pH meter present, to tweak the final pH at the desired temperature.

    Remember, the ratios give the pH range and the total quantity adjusts the buffer capacity of a solution.

    Usually, photo solutions are adjusted to within 0.1 pH unit at 20 degrees C with greater tolerance allowed in most cases for Fix, Bleach or Blix solutions.

    PE
     
  16. lee

    lee Member

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    I have a couple of Hanna PH Meters that were given to me by my ex-boss. Mine sorta eat batteries.

    lee\c
     
  17. dancqu

    dancqu Member

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    I've a Milwaukee SM 102 ph meter with temperature probe.
    Replaceable probe, two point calibration, automatic temperature
    compensation, +/- .01. www.milwaukeetesters.com
    About $100. Dan
     
  18. DarkroomExperimente

    DarkroomExperimente Member

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    thanks...

    I think I'm going to just get some litmus paper strips to start since I'm doing pretty basic experiments for now...and I'll upgrade to a "real" meter when I get into more serious stuff
     
  19. Photo Engineer

    Photo Engineer Subscriber

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    Remember that litmus paper strips are hard to read under safelights. :D

    PE
     
  20. dancqu

    dancqu Member

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    In that case from Google enter, microessential lab .
    They have any of a few ways to check ph, water hardness,
    hypo silver levels, and ... Narrow range papers may be all
    you need. Paper and other means. Only $5 S&H. Dan
     
  21. DarkroomExperimente

    DarkroomExperimente Member

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    OK, looking at all the different Hanna meters is going to make my head explode

    IIRC they all seem to have automatic temperature compensation...

    I can't tell if the meters are shipped with calibration solutions...or if I need to get that too


    here is a selection of Hanna meters:

    http://www.caprockdev.com/pHmeters.htm


    here is a simple Hanna meter not shown on the caprockdev.com page:

    https://www2.carolina.com/webapp/wc...=47650&langId=-1&parent_category_rn=&crumbs=n

    I don't need anything fancy, it's just time to advance out of the stone age

    any pearls of wisdom out there?
     
  22. DarkroomExperimente

    DarkroomExperimente Member

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    OK, I'm not sure of the differences between these two...

    pH-2 (HI98103 Checker-1)

    HI99104

    the price difference is $1

    As far as I can tell, the new one (99104) has automatic temperature compensation...but it doesn't say if the "Checker" does or not
     
    Last edited by a moderator: Dec 14, 2007
  23. DarkroomExperimente

    DarkroomExperimente Member

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    and how important is temperature compensation if I'm not doing anything critical & test in a narrow temp range anyway??
     
  24. Photo Engineer

    Photo Engineer Subscriber

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    That is a hard one to answer.

    When making emulsions, the pH is measured from 20 C to 40 C, but standardization is at 20 C. When processing, regardless of process temp, again over the same range, or emulsion making, standard temp is considered to be 20 C.

    PE
     
  25. DarkroomExperimente

    DarkroomExperimente Member

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    I'll just be using it to test pH of my homemade developers
     
  26. Photo Engineer

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    Use 20C.

    I did in the lab all the time.

    PE