Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,222   Posts: 1,532,358   Online: 1116
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 29
  1. #1

    Join Date
    Nov 2007
    Location
    Washington DC area
    Shooter
    Multi Format
    Posts
    596

    pH Meter Suggestions

    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. #2
    Mike Wilde's Avatar
    Join Date
    Aug 2006
    Location
    Misissauaga Canada
    Shooter
    Multi Format
    Posts
    2,939
    Images
    29

    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. #3

    Join Date
    Nov 2007
    Location
    Washington DC area
    Shooter
    Multi Format
    Posts
    596
    thanks....

    anyone have a preference between Hanna & Oakton pH Meters??

  4. #4
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    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. #5

    Join Date
    Nov 2002
    Location
    Melbourne, Australia
    Shooter
    Medium Format
    Posts
    979
    For what they are worth, there are some comments by Ryuji Suzuki here:

    http://wiki.silvergrain.org/wiki/PH

  6. #6
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    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. #7

    Join Date
    Mar 2004
    Location
    Southern California
    Shooter
    Multi Format
    Posts
    3,879
    Images
    11
    Quote Originally Posted by Photo Engineer View Post
    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
    I also use a Hanna meter and have found it to be stable and reliable.
    Tom Hoskinson
    ______________________________

    Everything is analog - even digital :D

  8. #8

    Join Date
    Nov 2007
    Location
    Washington DC area
    Shooter
    Multi Format
    Posts
    596
    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. #9
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    It is good, but is overstating the case, or is overcautions. IDK which and IDC.

    PE

  10. #10

    Join Date
    Nov 2007
    Location
    Washington DC area
    Shooter
    Multi Format
    Posts
    596
    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

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin