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  1. #11

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    Barry Thornton's divided developer (discussed extensively in other threads on this forum) is a little like D23 with a metaborate afterbath. I'm using it more and more these days -- very cheap, very reliable.

  2. #12

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    I noticed that leader snippets developed in Bath A only in daylight show signs of change in one minute, signficant change in two, and pretty much done in in three. At 80 degrees, very active. So yes, how much Bath B does in bringing things out, I doubt any. Maybe more time to bring up shadow details.

    But folks, can we get back to my observations and questions? It wasn't so much about two bath observations, but ascorbic acid/ascorbate doing weird things and non-repeatability. That's what I need help on.

  3. #13
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    Ascorbate developers are sometimes known for being non-repeatable. This is due to the rapid (sometimes) decomposition of the ascorbate ion in solution. The result in a developer is that you start using both developing agents and gradually end up using one.

    To test this, make a developer like you started with but no ascorbate. Same pH and everything, but just metol. You will probably get the less satisfactory result that you describe or maybe worse, indicating that all of the ascorbate was gone, or was half gone or whatever.

    IDK for sure, but Metol also goes bad. Maybe they both interaced and you have some intermediate level of both.

    PE

  4. #14

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    Quote Originally Posted by Photo Engineer View Post
    Ascorbate developers are sometimes known for being non-repeatable. This is due to the rapid (sometimes) decomposition of the ascorbate ion in solution. The result in a developer is that you start using both developing agents and gradually end up using one.

    To test this, make a developer like you started with but no ascorbate. Same pH and everything, but just metol. You will probably get the less satisfactory result that you describe or maybe worse, indicating that all of the ascorbate was gone, or was half gone or whatever.

    IDK for sure, but Metol also goes bad. Maybe they both interaced and you have some intermediate level of both.

    PE
    That certainly seems to be the case, that is, about inconsistencies with ascorbates. We all know of the Xtol disaster. What I don't understand is why after mixing new developer with the minor changes noted, I could not replicate what I got that first time.

    I've done another experiment unlike the others. Since ascorbate is a sort of hydroquinone sibling, I wondered if I could get activity in a high pH solution. In 100ml of water I put in 1/2 tsp of ascorbice acid, enough bicarb to stop fizzing, and 1/4 tsp of carbonate. Into that, I placed two leader ends, TMY and TX. After about an hour, very little had happened, some graying. Pretty much like phenidone that can't get density by itself.

    I added "a bit" sodium hydroxide, no visible change. I added "a bit" of Metol and away it went! Very high Dmax, could not see the kitchen light through it when held to my eye, unlike other snippets.

    Presuming that HQ would have provided a high Dmax in that very high pH solution, we can see that ascorbate is not exactly a twin.

  5. #15
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    Paul;

    First off, ascorbic acid is not related to HQ in any way chemically and even as far as fundamental activity goes, and that is a basic misunderstanding of many people.

    It is so sensitive to some impurities that otherwise normal tap water can change enough to catalyze decomposition, as can the amount of stirring. AA is very weak all by itself. It needs something to go with it. Metol is very strong and can go by itself, as can HQ.

    We used what we called EAA developer at Kodak for basic R&D. That stands for Elon/Ascorbic Acid. It is very clean working and when properly mixed is quite stable stored in glass bottles.

    So, your last paragraph has probably proved to you that the statement about "HQ sibling" is wrong.

    PE

  6. #16
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    One can get a sort of semi-rectum (to put it in polite terms) high contrast developer for line drawings and the like out of ascorbic acid, caustic soda, lots of KBr, and sulfite, but it is not as good as the hydroquinone equivalent. One can make a good MQ developer or a good MA developer, but they have different characteristics, and the MQ developer must have sulfite in order for the Q to do any good at the pH of, say, borax, while the MA will work without sulfite when the A is sodium or potassium ascorbate. Ascorbic acid, p-aminophenol base and Phenidone are soluble in propylene glycol, glycerol or TEA and keep well in those solutions until water is added. As PE has said, it is not proper to call ascorbic acid or the ascorbates "siblings of hydroquinone". Shakespeare had his character say "What's in a name?" but in this case, they don't really smell the same.
    Gadget Gainer

  7. #17

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    Quote Originally Posted by Photo Engineer View Post
    Paul;

    First off, ascorbic acid is not related to HQ in any way chemically and even as far as fundamental activity goes, and that is a basic misunderstanding of many people.

    It is so sensitive to some impurities that otherwise normal tap water can change enough to catalyze decomposition, as can the amount of stirring. AA is very weak all by itself. It needs something to go with it. Metol is very strong and can go by itself, as can HQ.

    We used what we called EAA developer at Kodak for basic R&D. That stands for Elon/Ascorbic Acid. It is very clean working and when properly mixed is quite stable stored in glass bottles.

    So, your last paragraph has probably proved to you that the statement about "HQ sibling" is wrong.

    PE
    I meant a functional sibling, not chemical, PE. Similar to HQ as a superadditive ingredient.

    Soooooooo.....what was the EAA formula? AKA Xtol?

    I'm using food grade ascorbic acid, so one would hope that the impurities would be minimal. It is those that allegedly makes AA misbehave and die early. Of course, they could come in with the tech grade sulfite or Metol, too. I use distilled water.

  8. #18

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    Quote Originally Posted by gainer View Post
    they don't really smell the same.
    I tested your theory. I snorted a line of each. The HQ made me see everything in high contrast. The AA was so acidic and painful I had to neutralize it with a line of hydroxide......

  9. #19

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    Quote Originally Posted by Paul Verizzo View Post
    I meant a functional sibling, not chemical, PE. Similar to HQ as a superadditive ingredient.

    Soooooooo.....what was the EAA formula? AKA Xtol?

    I'm using food grade ascorbic acid, so one would hope that the impurities would be minimal. It is those that allegedly makes AA misbehave and die early. Of course, they could come in with the tech grade sulfite or Metol, too. I use distilled water.
    When you mix the Ascorbic Acid with water, it starts to degrade.

    Gainer's advice to dissolve the AA in Glycol is good advice for long shelf storage.

    The purity of your distilled water is very dependent on how it was distilled.

    Also, What's the pH of your distilled water? (Don't assume that it is neutral pH).

  10. #20
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    I have to agree with both Patrick and Tom here!

    PE

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