Ascorbate adventures, good and bad

Discussion in 'B&W: Film, Paper, Chemistry' started by Paul Verizzo, Nov 17, 2008.

  1. Paul Verizzo

    Paul Verizzo Member

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    I thought I'd do some experiments win Ascorbic acid; I think I've found every link on the internet. Of course, many were Gainer's or he contributed to others. Since I'm not a big fan of time/temperature, my interests leaned towards divided development or reduced agitation stand development.

    So, at the suggestion of Jay de Fuhr (??) I mixed up as follows:

    5 g Metol
    20 g AA
    20 g sodium sulfite (my contribution)

    I then added sodium bicarbonate until the fizzing stopped. pH, 8.4.

    For my Bath B, I used trisodium phosphate, tech grade, 1/2 tsp in a liter, pH 10.5. I intentionally wanted to try TSP at a low unbuffered rate for two reasons: One is I wanted high density areas to run out of steam, so to speak, and two, TSP doesn't swell gelatin and encourages finer grain (per Haist.)

    I developed a roll of TMY-2 at 3 minutes each bath at about 80 degrees. At a glance the frames looked nice, but not special. Well, once I put the loupe on them with a proper light source, I was astounded! Beautiful grain, lots of local contrast. They practically jumped out at me. Whoopee!

    Well, I can't duplicate that! I then developed a roll of Arista Premium 100. The shots tended towards muddy like overdevelopment everywhere, lots of fog (more like mud) in the low exposure zones.

    I ran test snippets, both of frames and just leader ends, watching the latter develop in the light. The latter always came to a good eyeball Dmax. So I'm thinking the developer had not lost its activity. I also tried a double dose of TSP for pH 11.5.

    I gave up and remade the developer. Slight variations: 17.6 g of AA, 4 g of sodium hydroxide. pH, 8.4. With some new test frames, like, dude, all but no development took place! Was my camera off? I'll have to check that. Dear Santa: all I want is the first result I got, all of the time!

    Now, let me tell you about my attempts at using ascorbic acid in reduced agitation/stand development. I won't go into a lot of detail (do I hear cheers?) but the bottom line is all I can get is mud. I developed a test frame using my metol/sodium sulfite dilute developer for 60 minutes, looks good. I add a small measured amount of ascorbic acid, I get mud. I took the above developer, diluted it, and got mud. Score, 0-2.

    I will double check my two camera's metering, but there are obviously other issues here.

    Is this weird or what? What say you?
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    The two films have different Iodide content I would guess, and the grain sizes are different and .....

    Well, you get the picture!

    Sounds a bit like overdevelopment in the latter case (Arista) for some reason.

    Films are cranky, and there is a definiite science to developing a developer... pun intended.

    BTW, it is Jay de Fehr.

    PE
     
  3. Paul Verizzo

    Paul Verizzo Member

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    Yeah, but........ I think you've seen I'm a fair amateur chemist in these matters. And I know that ascorbates are still somewhat of an inconsistent mystery in practical use. But that no one has picked up on similar issues?
     
  4. T Hoskinson

    T Hoskinson Member

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    I use several developers that incorporate ascorbates (including Pyrocat M-C, Instant Mytol and PC Glycol). I have found them to be consistent performers.

    1. How did you make your test exposures?
    2. Did you include exposure(s) of a step wedge?
    3. Did you evaluate your results with a densitometer and a microscope?
    4. What film/developer/ test subject did you use as a control?
     
  5. Paul Verizzo

    Paul Verizzo Member

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    Nothing quite so scientific, sorry to report. My test exposures are usually just a motor drive blast of my backyard in full sun, which includes a bayou and a boatyard, with a 28mm lens to gather many zones. I know that's a bit of a crap shoot, but as long as each test in the developer is the same, it's a point of reference. I know where to look for low zone and high zone, uh, zones. And what I experienced as described is beyond the need for densitometers!

    No, No, and dilute D-76 when I get a new film.
     
  6. Paul Verizzo

    Paul Verizzo Member

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    Addendum: I meant to mention that I then take a few inches of the film that I "blasted" out of doors and develop it. It's just to get a general direction of what the developer is doing.
     
  7. Alan Johnson

    Alan Johnson Subscriber

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    The ascorbate fooled me for about a month when I thought I had made a two bath phenidone ascorbate developer and I ran this test on a formula similar to that in the original post:
    Part A
    Metol 5g
    Sodium Ascorbate 22.6g
    Water to 1000ml
    Part B
    Sodium Carbonate anh 5g
    Water to 1000ml, pH~11.5
    Take 20 ml Part A and add to 500 ml Part B.
    It developed APX-100 film substantially after 4 min.
    What would happen if this Part A and Part B was used as a two bath developer is that development would occur due to 20ml Part A being carried over on the film, tank and reel making the part B an ordinary non-exhausting developer.It would not be a true two bath developer where development occurs in the developer absorbed in the film emulsion.20 ml is a typical amount of carry-over in my tank.
    I wonder if this development in carry-over is occurring with the developer formula given in the original post.
     
  8. gainer

    gainer Subscriber

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    Numerous years ago the idea of using D-23 as part A of a two bath developer with a borax solution as B became a sort of fad. I thought it was miraculous until I got the necessary tools to make H&D curves. I found there was not a nickel's worth of difference in curve shape between D-23 and the 2-bath version.

    If you use p-aminophenol base or phenidone in place of the Metol, you can use propylene glycol as solvent for part A. You can experiment with various activators for part B, including triethanol amine (TEA), sodium metaborate (part B of PMK works well), carbonate, etc. There is less chance of change of part A with time if you use glycol or glycerol as the solvent. Whatever you get the first time is more likely to be repeatable. A modicum of KBr may help keep the fog away. I would say, however, that it's not a good idea to reuse the part B in any case.
     
  9. analogsnob

    analogsnob Member

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    I used to use d-23 with metaborate as a B bath. It supported the shadows on minus development and I have the curves to prove it. That was a while ago but if films now are so thin it nolonger works then two bath developers don't have a snowball's chance in you know where. A two bath requires alot more developement to take place in the B than d-23 did.
     
  10. gainer

    gainer Subscriber

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    Was it better than just plain D-23? I did a direct comparison years ago. Haven't bothered with the two bath since.
     
  11. Jordan

    Jordan Member

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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.
     
  12. Paul Verizzo

    Paul Verizzo Member

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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.
     
  13. Photo Engineer

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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
     
  14. Paul Verizzo

    Paul Verizzo Member

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    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.
     
  15. Photo Engineer

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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
     
  16. gainer

    gainer Subscriber

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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.
     
  17. Paul Verizzo

    Paul Verizzo Member

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

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

    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.
     
  18. Paul Verizzo

    Paul Verizzo Member

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    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......
     
  19. T Hoskinson

    T Hoskinson Member

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    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).
     
  20. Photo Engineer

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    I have to agree with both Patrick and Tom here!

    PE
     
  21. Paul Verizzo

    Paul Verizzo Member

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    Comments in Bold

    Silly system won't let me post only above, so this is just filler.
     
  22. T Hoskinson

    T Hoskinson Member

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    When you add pure, clean water to AA, the AA begins to oxidize. If the water is alkaline or acid the oxidation/degradation process will accelerate. In addition, if the distilled water contains metal ions, undesirable chemical reactions may take place.

    At my workplace lab, we often need to reject commercial Deionized water for out-of spec pH.
     
  23. Paul Verizzo

    Paul Verizzo Member

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    Starting to sound like the bumble bee that can't fly. There are ascorbate developers out there and they use whatever water the user has.

    My questions and observations remain unanswered.
     
  24. T Hoskinson

    T Hoskinson Member

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    Paul, Please Review P.E.s posts, Gainer's posts and my posts on the subject of Ascorbic Acid developer shelf life and working solution life. And, if you have not yet done so, read Jordan's APUG article on Instant Mytol

    http://www.apug.org/forums/forum223/33880-instant-mytol.html
     
  25. Photo Engineer

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    I said we used an Elon Ascorbic acid developer at Kodak. I did not say it used Kodalk. In fact, I cannot remember what it used as alkali!

    PE