sulfite solution and hydroquinone

Discussion in 'Darkroom Developing and Printing' started by sreenath, Jun 19, 2007.

  1. sreenath

    sreenath Guest

    Hi All,

    While going through an old book on Photography by
    L.P.Clerc(Photography: theory and practice), I came across the
    following interesting piece:

    "Sulfite solutions do not keep well, therefore preparation of solution
    is not advised. If absolutely necessary, a 20 percent solution can be
    prepared and a small quantity (5 %) of either p-aminophenol or
    hydroquinone can be added to protect the sulfite solution."

    I forget the exact words, but the above is the essence.

    I am really surprised. I have always assume that it is sulfite that
    protects developing agents like hydroquinone and aminophelos, and here
    I see the opposite.

    So when we prepare D-76 and D-72, are we protecting the hydroquinone
    or the sulfite!!??

    sreenath, Jun 19, 2007
    1. Advertisements

  2. One problem with Clerk is that there are no attributions or
    citations. Sulfite slowly absorbs oxygen becoming Sodium Sulfate. In a
    developer or fixing bath its affinity for oxygen is used to protect
    other chemicals by preferential absorption. Hydroquinone and Metol are
    also oxygen absorbers but, like you, I've never heard of adding any
    to a Sulfite solution to preserve it.
    Generally, the more concentrated a sulfite solution it the longer
    it will last. Probably the best way to preserve a sulfite solution is
    to keep it in a closed, sealed container of some material which does
    not allow air to pass through. Glass is best but some high density
    plastics are nearly as good.
    The various editions of Clerk's books have a lot of good stuff
    in them but, IMO, the lack of citations and references severely limits
    Richard Knoppow, Jun 19, 2007
    1. Advertisements

  3. The only copy of L.P. Clerc I have seen is an English translation in two
    volumes. These seem to be intended for English students who want a career in
    photography. I know some color illustrations (all of them) are missing,
    though referred to in the text. Could it be that a French edition would
    contain the citations? L.P.Clerc was a scholar, among other things, and it
    seems unlikely that he would have left out the citations.
    Jean-David Beyer, Jun 19, 2007
  4. I have several editions of Clerk, all English
    translations. The forward indicates that citations were
    delibrately left out to reduce the size and cost of the
    book. I am quite sure they didn't exist in the original
    French editions. There are a few citations in the text,
    mostly just to names, with no indication of where to find
    them, so its very difficult to trace down original sources.
    The first two or three editions were published in a
    single volume. Then the book was taken over by Focal Press
    who broke it up into several small books. Focal tends to do
    this sort of thing. Clerk remains a valuable book but the
    value is very much reduced by the lack of references.
    Richard Knoppow, Jun 19, 2007
  5. sreenath

    sreenath Guest

    This is 2nd English edition, and L.P.C does state in the foreword that
    references have been intentionally left out.

    I searched through the book again, and found that the original paper
    is by Lumiere and Seyewetz, 1905.

    Here is the exact text :

    "It should, moreover to be noted that several developers, particularly
    HQ and paraminophenol), if added i very minute quantity to a solution
    of sulphite, retard very markedly the oxidation of the latter by
    oxygen of the air(Lumiere & Seyewetz, 1905). They probably oppose the
    catalytic action of various metallic salts, especially copper salts,
    which may be present in quantities so small as to escape detection"

    In another page, he states the quantity of developer to be added as 5
    gr ( I think grains) to 20 Oz of sulfite solution.

    Perhaps this is no longer of practical significance.

    I find this book really fascinating.

    sreenath, Jun 21, 2007
  6. I have the 2-volume Amphoto edition edited by D.A.Spencer -- the one
    published in USA in 1973 and copyright in 1970. This has no Forward, but it
    does have a Preface by Spencer. It is Spencer who says that the references
    have been left out (to save space). He does not say the color plates have
    been left out, though they have been left out even though they are cited in
    the text. I think the omissions are due to the English editors trying to
    appeal to English trade-school students, rather that to Clerc himself
    (though this is just my opinion).
    Jean-David Beyer, Jun 21, 2007

  7. This is also true of the english translation of Eder's
    history. The original German edition had many illustrations
    which were left out. They were included, or others
    substituted, in the Dover reprint. I am they were left out
    of the english translation to lower the costs and Focal does
    seem to target trade school students with many of its books.
    Richard Knoppow, Oct 30, 2007
  8. Both hydroquinone and paraminophenol and its relative
    Metol, are very active reducing agents, i.e., they absorb
    oxygen. There may be some mutual protection where both
    sulfite and one of these developing agents is included. If
    so, it would suggest that the liftime of low pH developers,
    like D-23 or D-25, is longer than the lifetime of a similar
    concentration of sulfite. I don't know how to prove this
    since I am not a chemist. One clue may be that the shelf
    life of Kodak Hypo Clearing Agent, which is a neutral pH
    buffered solution of sodium sulfite _does_ have a shorter
    shelf life than many relatively low pH developers. I will
    have to dig out my edition of Clerc and find this. I have
    both the first and second edtions in translation plus the
    later Focal Press edition in 5(?) volumes. I agree that its
    a fascinating book.
    Lumiere and Sayewetz are very respectible researchers and
    photographic pioneers.
    Richard Knoppow, Oct 30, 2007
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.