a mild bleach

Discussion in 'Darkroom Developing and Printing' started by Lew, Feb 17, 2009.

  1. Lew

    Lew Guest

    Ugh... it seem the last batch of prints I did was on a somewhat too old
    paper .... I've since cleaned up the whites be increasing the restrainer,
    but I'm still left with a number of prints with slightly grey whites. Can
    anyone recommend a mild bleach I could use to clean them up?
    Thanks.
     
    Lew, Feb 17, 2009
    #1
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  2. Lew

    Peter Guest

    Did you check your safelight?
     
    Peter, Feb 17, 2009
    #2
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  3. Lew

    Lew Guest

    .... this is definitely fog & old age. As I originally posted, other papers
    process just fine & the problem for this paper is cleared up by adding
    restrainer. Do you have any experience cleaning up highlights by bleaching?
    ..
    Did you check your safelight?
     
    Lew, Feb 17, 2009
    #3
  4. Lew

    Lew Guest

    Sodium thiosulfate (crystalline)
    Is this the same as Pentahydrate?
     
    Lew, Feb 17, 2009
    #4
  5. Ansel Adams gives the following bleach for prints to clear the highlights. I
    infer his use of this process was not to save old paper, but to arrange a
    little more detail in the highlights.

    Solution A

    Water (room temperature) 300 ml
    Potassium ferricyanide 62.5 gm
    Potassium metabisulfite 4.2 gm
    Water to make 500 ml

    Solution B

    Water (room temperature) 600 ml
    Ammonium thiocyanate 330 gm
    Potassium bromide 30 gm
    Water to make 1 l

    Mix 1 part of a, 2 parts of B and 10 to 15 parts of water. Immerse the dry
    print face up with vigogous agitation for 5 to 10 seconds. Place immediately
    in water and agitate until the bleaching solution has been removed from the
    surface of the print. Examine the print , and return it if necessary to the
    bleaching bath (advised only for a few seconds). If the print is wet
    initially, or if the solution is too dilute, the middle and the lower tones
    may respond to the action of the bleach, thereby weaking the print values in
    general.


    I advise being very careful with this or it will get away from you.
     
    Jean-David Beyer, Feb 17, 2009
    #5
  6. Lew

    Lew Guest

    Thanks, I've lost track of my Adam's books over the years.
     
    Lew, Feb 18, 2009
    #6
  7. Lew

    darkroommike Guest

    Bill Pierce used to recommend a simple bleach of just potassium
    ferricyanide in water and move the print back and forth between the
    bleach and a tray of plain fixer; most Farmer-type reducers combine
    this in a single formulation but this also works. His recommendation
    was for a very pale straw color in the "ferri" the fixer functions as
    a sort of stop bath but removes the reduced silver also. A stronger
    ferri solution in a small container can be used with a non-metallic
    brush or cotton swab to selectively bleach highlights and again into
    the fixer between applications. His last recommendation was to try to
    stop short of where you thought you needed to be with the bleaching
    since there's some lag before clearing stops. You can use a fixer of
    straight sodium thiosulfite and you obviously do not want to reuse the
    fixer. Clean up is down the sink with lots of water. Prints should
    be refixed and washed as usual.
     
    darkroommike, Feb 20, 2009
    #7
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