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  1. #11

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    Quote Originally Posted by Snapshot View Post
    Throw all the data sheets and Haist quotes you want as I'm not arguing that TEA isn't used as an accelerator (nor am I'm arguing salicylic acid isn't being used as a chelator). However, I am under the belief that Ryuji included TEA in DS-14 to act as a chelating agent. Salicylic acid is included as an iron chelating agent but it doesn't preclude other agents being added, unless there is some law that I am unaware of that precludes such.

    The question that was posed is why TEA included in DS-14, a Ryuji formulation. I'm very doubtful it was intended an alkali accelerator as 5ml not enough to provide this action. That is why there is 30 grams of carbonate. It very possible TEA has been included as a buffering agent. However, with DS-14 having a pH 10.4 I'm a little doubful of this. Regardless, Ryuji has clearly stated that he used TEA as a chelating agent. Anyway, unless someone knows his mind this isn't going to get settled.
    Why don't you PM Ryuji and ask him?
    Tom Hoskinson
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  2. #12
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    Quote Originally Posted by Tom Hoskinson View Post
    Why don't you PM Ryuji and ask him?
    D'oh, why didn't I think of that?
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  3. #13

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    No need. Somehow the wind pushed me this way.

    I know what's in my mind, and I tell you that the main purpose of TEA in DS-14 is iron and copper chelator. It is true that I use TEA for some other purposes (e.g., alkaline buffer, radical scavenger, solvent and what not) in other developers, but as you correctly pointed out before, these roles are largely irrelevant in DS-14, with possible exception of radical scavenger. Salicylic acid is also intended as an iron chelator (and again, also a radical scavenger), but the effect of both used together is superior. If only one is used, I would have to use a lot more. Since these agents do not directly contribute to developing reaction, these agents are eventually carried over to stop or somehow discarded. So, it is my best intention to minimize the chemical waste and save some pennies. The quantities of TEA and salicylic acid are rather small, but you'll see improved keeping properties. I keep my DS-14 and Tektol developers in my slot processors for months. One key factor I found to influence the shelf life (without complete airtight closure) is ambient temperature. DS-14 gets oxidized faster in open trays in a hot darkroom (in a closed, full glass or PET bottles, this is irrelevant).

    I've tried many chelators and radical scavengers, and these are two of my early hits. Now I know some better ones but they've become my favorite chemical tricks and I still use them a lot when they can do the job.

    I might also add that, in photographic chemistry (both emulsion making and processing chemicals), it is not uncommon to see one agent used in different places for distinct functions. It is also not uncommon to see one agent playing multiple roles in one solution. Sulfite in developer is a prime example.

  4. #14
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    Thanks for clarifying, Ryuji.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  5. #15
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    Perhaps the TEA along with the salycilic acid should be considered as a more-or-less neutral chelating agent in the phenidone-ascorbic acid-carbonate developer. I would not expect Ryuji to take the "let's put a little XYZ in there and see what happens" attitude. Having a working PAC combination, a theory about the effect of that particular valence of iron on the ascorbate, and a theory about the effect of a salicylate on the iron, I would expect him to use a neutral solution of salicylate of some sort to test the theory and determine the required amount if it works. OTOH, what was it someone once said about the difficulty Occidentals have understanding the Oriental mind?

    I have noticed that some of us try to treat the effect of each ingredient separately without considering various possible combinations. If we added ammonium salicylate, we might look at it from a different perspective than adding ammonium hydroxide and salicylic acid separately. Try thinking of the TEA as an organic analog of ammonia. Perhaps methyl salicylate would work as a replacement for both TEA and salicylic acid. If so, the developer might have an enticing odor of Wintergreen.
    Gadget Gainer

  6. #16

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    I do try a lot of things for screening. But I then have an array of large vials with one base developer and one additive in a vial... with one blank control. Then I adjust the pH of each vial with NaOH or sulfuric acid. ... and test them all. The thing is that you kinda have to select the range of additives wisely, because there are so many compounds and my array can hold max of only 24 at a time. Salicylic acid and triethanolamine were not randomly selected for inclusion, tho.

    Ammonium salts in developers are not recommended. It'll smell like ammonia in an alkaline solution. It has a very strong solvent effect and can deteriorate granularity and also can cause dichroic fog with some emulsions. It is definitely not recommended in print developers.

  7. #17

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    Ammonium salts at alkaline pH is a strong silver halide solvent, and it was once used popularly in making of high speed iodobromide emulsions (this is called a ripener, to enlarge grain sizes to gain speed). It is rather convenient because the solvent effect can be turned on or off by adjusting the pH. However, at the higher pH where the effect is used, the emulsion also gets different effects (which can be useful in some cases, but in others it leads to elevated fog and not very desirable) and also the vapor of ammonia is objectionable, so it got replaced with a number of alternatives in modern practice. (I personally do not use ammonia in my emulsion making but can make ISO 1000 emulsions.)

    Triethanolamine has only a weak solvent effect, on the other hand. It is more easier agent to use in developers, as the risk of dichroic fog is pretty low.

    (Although modern films have the top coating layer incorporating compounds that prevent dichroic fog from most reasonable developers...)

  8. #18

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    So Skip the TEA and Salicylic Acid?

    Use distilled water for same results? Dan

  9. #19

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    No. I've said many times that the impurities come with other chemical stocks, not just water.

    How many reports of sudden XTOL death using distilled water?

    Got the point?

  10. #20

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    Radical Scavengers?

    Quote Originally Posted by Ryuji View Post
    , radical scavenger.
    Is this something the police wished they had in the sixties? Especially at the Chicago Democratic convention? :rolleyes:

    Or, just what radicals are in developers?

    Thanks,

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