Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,205   Posts: 1,531,777   Online: 918
      
Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 37
  1. #11

    Join Date
    Sep 2002
    Location
    Willamette Valley, Oregon
    Shooter
    Medium Format
    Posts
    3,684
    Quote Originally Posted by Maine-iac
    Once exposed to air, over time, it will cease being
    the anhydrous form anyway. Larry
    You are saying the anhydrous will absorb H2O from
    the air. I think that true. I believe the mono-hydrate
    is the most stable of the carbonates. It is most often
    the form mentioned.

    Years ago I placed some bicarbonate in boiling water
    and it effervesced greatly. What was left? A mix of
    two or just the carbonate? Dan

  2. #12
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    A mixture of sodium carbonate, water and carbonic acid. Maybe about as much carbonic acid as is left in pepsi after you boil it.
    Gadget Gainer

  3. #13
    raucousimages's Avatar
    Join Date
    May 2003
    Location
    Salt Lake
    Shooter
    Large Format
    Posts
    825
    Sounds like a lot of work. I buy it for $4.00/LB from a local chemical supplyer.
    DIGITAL IS FOR THOSE AFRAID OF THE DARK.

  4. #14
    BradS's Avatar
    Join Date
    Sep 2004
    Location
    S.F. Bay Area, California
    Shooter
    Large Format
    Posts
    3,980
    Quote Originally Posted by raucousimages
    Sounds like a lot of work. I buy it for $4.00/LB from a local chemical supplyer.
    Some say that developing film is a lotta work too. I did it because I had read about the process and wanted to try it. It really wasn't much work.....turn on the oven , go to the pantry and get a box of baking soda, open the box and pour it out into a baking tray, put it in the oven and set a timer. Surf the net while watching the timer. Get up and give the powder a stir every once in a while.

    I can buy sodium carbonate from the local supplier too but, I'd have to drive 40 miles round trip and then they'd want to give my name, address and driver's license number to the US Department of Homeland Security. I'd have to live life watching over my shoulder all the time...what a pain.

    Baking soda cost $1.20 per pound at the local grocery store...and, I can walk there.

    I'd rather cook baking soda.
    Last edited by BradS; 06-04-2006 at 01:05 AM. Click to view previous post history. Reason: typos...

  5. #15
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    Order it from www.chemistrystore.com. They ship it to your house. Get 25 pounds, they don't care. Use it to make your own detergents. A mixture with clorox is a a very good cleaner for bathtubs and the like.
    Gadget Gainer

  6. #16
    Maine-iac's Avatar
    Join Date
    Oct 2004
    Location
    Island Heights, NJ, but will retire back to Maine.
    Shooter
    Med. Format RF
    Posts
    464
    Quote Originally Posted by raucousimages
    Sounds like a lot of work. I buy it for $4.00/LB from a local chemical supplyer.
    I pay about $2.00 for a two-pound box of Washing Soda at our grocery store. Makes a heck of lot of developer. Arm & Hammer has also removed all or most of the objectionable perfume smell they gave it several years ago. The newer stuff doesn't have much of an odor at all.

    Larry

  7. #17

    Join Date
    Mar 2004
    Posts
    67
    The same can be said for a very small amount of fixer getting into the developer. It will poison the developer. We have not found your fears or carry over issue to be a concern. Perhapse it is because there is not enough potassium salt in the developer to become an issue.

  8. #18
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    Quote Originally Posted by lowellh
    The same can be said for a very small amount of fixer getting into the developer. It will poison the developer. We have not found your fears or carry over issue to be a concern. Perhapse it is because there is not enough potassium salt in the developer to become an issue.
    The difference being that you normally do not process in reverse, so that fixer getting into the developer is less common than developer getting into the stop and fix. In fact, getting developer into the stop and fix is an assured event. The reverse is an accident.

    The data are to be found in Mees and James along with the tests they ran. Potassium ion is not good in fixers. The rate of slowdown is easily measured, but, not knowing your developer formula, I could not predict the rate of change.

    PE

  9. #19

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    The amount of carry over of developer into the fixing bath would have to be large. However, most people use some sort of stopbath even if it is only water rinse. So the amount of potassium ion reaching the fixer would be very small. I don't see the transfer of potassium ion to the fixer to be a serious problem.

  10. #20
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    Quote Originally Posted by Gerald Koch
    The amount of carry over of developer into the fixing bath would have to be large. However, most people use some sort of stopbath even if it is only water rinse. So the amount of potassium ion reaching the fixer would be very small. I don't see the transfer of potassium ion to the fixer to be a serious problem.
    Gerald, you may or may not be right. IDK.

    I know that when I was designing developers at EK, they taught us to avoid potassium carbonate in developers 'just in case'. And, never use them in fixers.

    Then I had to read some reports on the subject to show what happened with seasoned processes that used potassium salts in the developer, and reports on testing potassium salts in the fixer. So, I pretty much avoid them. It is possible to use them at rather low concentrations or to use certain potassium salts in developers.

    PE

Page 2 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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