Incorporating Developers?

Discussion in 'B&W: Film, Paper, Chemistry' started by dancqu, Nov 27, 2005.

  1. dancqu

    dancqu Member

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    DI, developer incorporated emulsions came up
    on an other subject thread. I thought it a good
    subject to be up front.

    I reviewed an article by Steve Anchell in Camera & Darkroom
    where he mentions the addition of a small amount of standard
    paper developer to the emulsion. Speed AND Contrast can be
    increased by doing so. He was working with Liquid Light.

    In my quest for whole-print contrast control techniques I
    did not ignore the mentioned Contrast Control. Steve added
    a little Selectol Soft but did not go into any detail at all
    save for mentioning a shortened emulsion life. Note,
    Selectol includes an activator.

    Such a simple approach; a pre-soak in a very dilute
    developer, dry, then expose. There may be some very
    interesting experimenting! Has anyone tried the method
    on any usual print paper? Dan
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    Dan, most papers sold today contain small amounts of incorporated developing agents.

    To test for this, add a drop of sodium hydroxide solution to the paper in the light. If it darkens or turns black, it contains an incorporated developing agent. If it does not, then there are no incorporated developing agents.

    This is not the traditional method of controlling contrast. Contrast has usually been controlled by metal salts, gelatin type, pH, and organic antifoggants.

    The keeping of these newer emulsions with developer incorporated is shortened, and cannot be improved much by refrigeration, as the decomposition is through aerial oxidation.

    PE
     
  3. dancqu

    dancqu Member

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    I thought I should confirm Freestyles claim of DI
    free Graded papers so I tested an Arista Gr.2 RC
    with Na2CO3. Zero indication. Perhaps the agent
    involved was not or was so little activated by a
    carbonate as not to show. Perhaps very minute
    amounts, none even, are present. So the
    Zero indication.

    So, from my reading of S. Anchell I'd suppose
    speed enhancement is the reason for the small
    amount of DI. If not for altering the contrast
    what other than altering the speed? Dan
     
  4. htmlguru4242

    htmlguru4242 Member

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    Dan, try using sodium hydroxide (NaOH) instead. Sodium carbonate works, but it needs to be in concentrated amounts.