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  1. #1
    Athiril's Avatar
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    Anything super-additive with ppd, CD2-4?

    I was wondering if there is any chemical super-additive with phenylene diamine, or Kodak CD-2 to CD-4? ie: Anything regenerative of oxidised ppd or CD-2 to 4?

  2. #2
    AgX
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    The oxidized state is essential for the coupling reaction.
    (You placed this in the colour section. But maybe you have something different in mind.)

  3. #3
    Athiril's Avatar
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    I placed in the colour section as I thought it'd be most appropriate for answers from people with any knowledge on these chemicals.

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    Ian Grant's Avatar
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    Pyrocatechin and PPD form Meritol, a once revered developing agent which was used in many of the Johnson's Scale Brand range of Chemicals which where highly regarded.

    MCM 100, Meritol-Metol were two commercial developers but there were more.

    Ian

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    Mike Wilde's Avatar
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    I have been chastised in the past for calling this formula anything similar to Harveys 777, but I have happily seasoned, used, replensihed and used over and over again the following formula. I don't know that they are superadditive, but I like the look of the negs. I process with this above 74F so that the glycin is active.

    Distilled Water 125F/- 700mL
    Pinch of sulfite
    Metol -7g
    Sodium Sulfite, any 70g
    p-Phenylenediamine (PPD) -7g
    Glycin -7g
    Distilled water to 1L

    Experimentally at 4/2008 the developer stock is being used as a replenisher. Long term results of doing this were not sceintifically evaluated, but I was happy with using the working 1L until 1L of the replenisher was added in, and did not notice over or under developed negs when sticking to the same time as when starting the litre after seasoning it with films at first.

    I was not sure if I should be going at 45ml per 80sq or 60mL- there are inconsistencies in the documentation I have found, so I repenished at the 60mL rate per roll. Once this product is seasoned, it is very economical and stable.

    Excluding the cost of shipping and taxes ( I buy all sorts of things over time and cannot isolate these) my cost of making up 1l of the working solution or replenisher is about $US4.50, and if I replenish at the 60mL rate my replenishment costs me about $US0.30 per 80 square inches of film. It is not a big deal if doing 35mm, but developer costs add up doing 11x14 contact negs from projected MF intermediate positives, as I have done with this developer

    This developer needs ‘seasoning’ to start – over develop a couple of dud rolls just to leach the silver bromide etc. out of them.

    Replenish, and keep the replenisher overflow – 200mL of it will ‘season’ 800mL of fresh developer.

    It will stain anything it touches – so use nitrile gloves when you work with it. Also exposure to the PPD is a good way to get severe dermatitis.

    It must be used above 72F; below this and the shadows drop away. The PPD energizes the glycin. – The glycin contributes the long unblocked S shaped curve – leads to ‘infinite highlights without blocking up. – i.e. a highlights glow.
    my real name, imagine that.

  6. #6
    Photo Engineer's Avatar
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    Quote Originally Posted by Athiril View Post
    I was wondering if there is any chemical super-additive with phenylene diamine, or Kodak CD-2 to CD-4? ie: Anything regenerative of oxidised ppd or CD-2 to 4?
    AFAIK, there is no easy way to regenerate PPDs. Once oxidized they are on their way to oblivion.

    There are a few chemicals that seem to act in a superadditive manner with PPDs, but they are rare and hard to come by. The method is not one generally used in B&W or color photography, but to make it more clear, it requires a coupler to take place and that is generally not acceptable.

    PE

  7. #7
    georgegrosu's Avatar
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    About 30 years ago, laboratory Mogosoaia for motion picture film is currently used ECP 2 recovered from the machine (~ 40 %). For more intensive reuse this developer ECP 2 we made tests with retention of oxidized form of CD 2 on resin. CD 2 is color developing agent for color print.
    Developer recovered flowing resin column will be filled with the active form of CD 2 and form oxidized low.
    I can say that it smelled pretty bad resin. It can regenerate.
    George

  8. #8
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    George;

    You can recover unoxidized CD2 from the developer but you cannot regenerate oxidized CD2. I've done what you describe and removed all salts and organics from developers leaving pure deionized water as the effluent, and the resin contains all of the salts and organics. It is quite tarry due to the oxidized developer.

    In addition, the free base of the PPD is very very prone to aerial oxidation and will go bad spontaneously on exposure to air. That is why they are supplied as acid salts or in Sulfite solutions.

    PE

  9. #9
    georgegrosu's Avatar
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    Our idea was to have in recovered developer much active form of CD 2.
    I could use it to prepare replenisher (we used 40% of the recovered developer from machine). May be an idea.
    George

  10. #10
    neelin's Avatar
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    Quote Originally Posted by Athiril View Post
    I was wondering if there is any chemical super-additive with phenylene diamine,
    Was rooting through a local University copy of Mees & James & ran across Phenidone superadditive to PPD (and also superadditive to Q & p-aminophenol)

    The citation was J.D.Kendall, BJP, 100, 56, 1953

    (Part of my "stupid hair-dye" rCw41 ppd developer project.)

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