Sodium Bromide vs Potassium Bromide

Discussion in 'B&W: Film, Paper, Chemistry' started by Bob Carnie, Jan 13, 2013.

  1. Bob Carnie

    Bob Carnie Subscriber

    Messages:
    5,479
    Joined:
    Apr 18, 2004
    Location:
    Toronto-Onta
    Shooter:
    Med. Format RF
    Mixing up a developer today and the formula calls for sodium bromide in the first developer,,,, postassium bromide heavily added to the second developer which is basically adding 400g of potassium bromide to my first developer.

    What is the difference between sodium and potassium bromide ... are they some what the same and interchangable???

    enquiring minds would like to know.
     
  2. Ian Grant

    Ian Grant Subscriber

    Messages:
    18,091
    Joined:
    Aug 2, 2004
    Location:
    West Midland
    Shooter:
    Multi Format
    Kodak published formulae with the option to use either so it's unlikely to make any difference.

    Ian
     
  3. Bob Carnie

    Bob Carnie Subscriber

    Messages:
    5,479
    Joined:
    Apr 18, 2004
    Location:
    Toronto-Onta
    Shooter:
    Med. Format RF
    That was incredibly fast Ian. within seconds... I love APUG

    so why would in my solarization/sabbatier developer concoction would Mr Jolly ask for a different bromide for the second developer.
    I assume its to change grain structure for the second flash image, which when toned would create more colourful prints which I do indeed see?

     
  4. Ian Grant

    Ian Grant Subscriber

    Messages:
    18,091
    Joined:
    Aug 2, 2004
    Location:
    West Midland
    Shooter:
    Multi Format
    I looked at Jolly's formulae and maybe the developer he adapted used Sodium Bromide, Potassium Bromide is much cheaper and also more common now. I can't see "which type" making much difference to grain structure.

    Potassium salts do help give slightly finer grain/warmer tones with warmtone papers but tht's when all the carbonate, sulphite etc is Potassium rather than Sodium, with low levels it's not likely to have an effect, but it might be worth a small test.

    Ian
     
  5. Bob Carnie

    Bob Carnie Subscriber

    Messages:
    5,479
    Joined:
    Apr 18, 2004
    Location:
    Toronto-Onta
    Shooter:
    Med. Format RF
    Thanks Ian

    If your in London now I would like you to meet a friend of mine, He has a portfolio of prints that I made for him, that I think you would enjoy.

    Bob