Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,701   Posts: 1,548,421   Online: 1039
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1

    Join Date
    Mar 2005
    Location
    Toronto
    Shooter
    Medium Format
    Posts
    175

    Substitute for 3% acetic acid

    I sometimes have to use a 3% solution of acetic acid to clear the sediment or "haze" I get on prints after doing sepia toning (with thiocarbamide). I find I only get this haze when I am doing full sepia, ie: bleaching all the way back and toning to completion.

    Anyways, the 3% acetic acid clears this. That tip must have been in the Darkroom Cookbook. I have literally gallons of Kodak Indicator Stop Bath, and only a small bottle of 28% acetic acid. Can I use the Kodak Stop bath instead? Does anyone know what the working strength of Kodak Indicator Stop Bath is?

    Thanks!

  2. #2

    Join Date
    Feb 2012
    Location
    Penfield, NY
    Shooter
    35mm
    Posts
    1,037
    White vinegar is about 5% acetic acid.

  3. #3
    paul_c5x4's Avatar
    Join Date
    Apr 2009
    Location
    Ye Olde England
    Shooter
    Large Format
    Posts
    1,478
    Images
    23
    Kodak StopBath MSDS gives 85-90% of acetic acid - Working strength solutions would be 1-5%.

  4. #4

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,865
    Quote Originally Posted by Prof_Pixel View Post
    White vinegar is about 5% acetic acid.
    The strength depends on the manufacturer. Some brands are only 4% so you need to check the label.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #5

    Join Date
    Sep 2002
    Location
    Oregon and Austria
    Shooter
    4x5 Format
    Posts
    839
    Kodak Indicator Stop should work just fine as long as the indicator dye has no effect on your prints. It shouldn't, since it has no effect on normally developed prints, but I don't do that much sepia toning, thus the disclaimer.

    Assuming that the Kodak Indicator Stop concentrate is 90%, you can just dilute 1+30 and get very close to (just under) 3%. Adjust as needed if the solution is too weak.

    Best,

    Doremus

  6. #6

    Join Date
    May 2005
    Location
    Daventry, Northamptonshire, England
    Shooter
    35mm
    Posts
    6,999
    Does the Darkroom Cookbook say what the chemical link is between thiocarbamide, complete bleaching, full sepia toning and the creation of a haze and why 3% acetic acid is the cure?

    Thanks

    pentaxuser

  7. #7
    eclarke's Avatar
    Join Date
    Jun 2004
    Location
    New Berlin, Wi
    Shooter
    ULarge Format
    Posts
    1,955
    Images
    71
    Glacial Acetic Acid is pretty easy to get and pretty cheap..White vingegar is even easier!!

  8. #8

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,865
    Quote Originally Posted by eclarke View Post
    Glacial Acetic Acid is pretty easy to get and pretty cheap..White vingegar is even easier!!
    Depends on the amount. I don't know whether the cutoff is at a pint or a quart but 1 gallon is subject to HAZMAT charges. What most people do not realize is that glacial acetic acid is flammable hernce the HAZMAT charge. Buying the 80% form will not incur this extra charge.

    Food grade glacial acetic acid is available which suggests a food service supplier as a source. Curiously this strength is also available as kosher.
    Last edited by Gerald C Koch; 10-13-2013 at 01:21 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #9

    Join Date
    Jul 2010
    Location
    Southern USA
    Shooter
    Multi Format
    Posts
    3,865
    Quote Originally Posted by pentaxuser View Post
    Does the Darkroom Cookbook say what the chemical link is between thiocarbamide, complete bleaching, full sepia toning and the creation of a haze and why 3% acetic acid is the cure?

    Thanks

    pentaxuser
    Since the haze is cleared by acetic acid I would say that it is caused by calcium carbonate being formed from hard water. The toner contains sodium carbonate in addition to thiocarbamide.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  10. #10

    Join Date
    May 2005
    Location
    Daventry, Northamptonshire, England
    Shooter
    35mm
    Posts
    6,999
    Thanks Gerald, that seems to make sense but it seems that it only happens to the OP when he does full bleaching but not partial bleaching and I cannot see how this is related. Maybe it is less a question of full bleaching and more a question of time since full bleaching will take longer as will full toning afterwards

    My other conclusion from what you have said is that it would also seem that if the water isn't hard then the haze won't happen. I have no idea how hard the water is in Toronto.

    The whole business of haze in relevant to me as in my part of the U.K the water is also classified as hard but there is hard and hard and Toronto water may have my water well beaten in the hardness stakes

    Am I on the right lines with my thoughts?

    Thanks

    pentaxuser

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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