Ascorbate paper developer

Discussion in 'B&W: Film, Paper, Chemistry' started by psvensson, Nov 19, 2004.

  1. psvensson

    psvensson Member

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    After great success with a phenidone/ascorbic acid film developers based on Patrick Gainer's formulas, I've been wanting to make paper developer with the same chemicals. However, I've had no luck.

    Here's one of my first tries:

    1.5 liters of distilled water
    1 tbsp sodium ascorbate (NOW Foods)
    20 ml phenidone in rubbing alkocol as per Gainer on unblinkingeye
    3 tbsp sodium carbonate, anhydrous
    3/4 tsp bromide (for contrast)

    This worked OK, except that the maximum black achieved was weak. Longer development did not help. Also, it exhausted quickly, giving even weaker blacks. The rapid change in color to pink, whether I used it or not, hinted that aerial oxidation might be the problem.

    The formula is similar to Chris Patton's E-72, which also contains sulfite. I tried adding sulifte to no avail.

    After a while, I realized that if I removed the phenidone, the bromide became unnecessary. The contrast acheived by just ascorbate and carbonate was a close match to Agfa Neutol, and gave a pleasing warm tone.

    Secondly, I found that if I exchanged the carbonate for sodium hydroxide, the maximum black improved. I'm a bit leery of this - I'd rather use carbonate than hydroxide for safety reasons.

    Now I have:
    1 L water
    1 tbsp ascorbate
    2 tbsp sodium hydroxide (Red Devil Lye)

    (if you mix this, add the lye to the water, not the other way around)

    The contrast and D-max now both match Neutol, but it still turns pink and dies in less than an hour. I've tried adding Calgon to no avail. I tried added Phisoderm, which is 2 percent salicylic acid, but that ruined the D-max.

    Any clues?
     
  2. Tom Hoskinson

    Tom Hoskinson Member

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    Take a look at the Ascorbic Acid paper formulas in the APUG Chemistry section.

    Comments:
    Sodium Sulfite has no effect on the activity of either Phenidone or Ascorbic Acid.

    Try adding more phenidone. BTW, phenidone goes off fairly quickly in alcohol so dissolve it just before you use it. Don't try to keep a stock solution in alcohol. Stock solutions dissolved in polyethylene glycol or TEA will keep for a very long time.

    Calgon is a water softener - it has no effect on developer activity and is not a preservative. Try adding phenidone and/or ascorbic acid. The ascorbic acid acts as a developer and a developer preservative. It is difficult to add too much phenidone, however, too little phenidone will cause some of the symptoms you describe.

    Bromide is a restrainer - it reduces developer activity. Start with no bromide and then add small amounts of bromide as a percentage solution - if needed. Benzotriazole should have a stronger effect with phenidone.
     
  3. psvensson

    psvensson Member

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    It does in film developers. But I was adding it hoping for an antioxidant effect, and that was a bust.

    I tried using this:
    1l water
    60 ml PG with phenidone and ascorbic acid as per Gainer
    1/2 tsp bromide

    It had less than maximum D-max and died quickly. I've tried PC-TEA too. In my experience more phenidone mainly affects the lighter values of the print, giving low contrast. So I had to add bromide to clear up the highlights and get the contrast to match commercial developers.

    Yeah, the Calgon was a long shot. I tried it because I note it's found in Dektol.
     
  4. Tom Hoskinson

    Tom Hoskinson Member

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    The ascorbic acid acts as the antioxidant/preservative, so sulfite is not needed in that role.

    In both film developers and paper developers that use a combination of Ascorbic Acid and Phenidone and no other developing agents, sodium sulfite has no effect on the rate of development. See Grant Haist's Modern Photographic Processing, Volume 1, Table 1, page 224.

    If Metol replaces the Phenidone in the mix, then sodium sulfite increases the rate of development.
     
  5. gainer

    gainer Subscriber

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    Did you really leave out the alkali, or was that slip of the keys?

    I have found that the ascorbate powders do not keep as well as ascorbic acid. By the way, erythorbic acid, AKA isoascorbic acid, is cheaper at www.Kicgroup.com than the vitamin C.

    Ascorbic acid and phenidone are superadditive in ratios up to 80:1. The curve relating activity to concentration looks like a curve of contrast vs developing time, levelling off at the higher ratios. The best preservative for ascorbate is more ascorbate. It does not form a sulfonate with any sulfite as do hydroquinone and metol. You may in fact preserve the sulfite with the ascorbate. Excess ascorbate is a better way to go with paper than excess phenidone.

    I have left PC paper developer in the tray overnight with little or no loss of activity, though I usually mix it fresh for each session. Tom's suggestion about using a glycol as solvent for the phenidone is good. You can use ordinary glycerine as well if you don't mind the extra viscosity. Propylene glycol is a double alcohol, so to speak, and glycerine is the triple. I seem to recall that one is 1,2 propanediol and the other is 1,2,3 propanetriol. Anyway, you can try it out quickly by using glycerine, although drugstore prices for small amounts are greater.

    I generally use sodium carbonate as alkali, but if I use my tap water, I get a lot of calcium and magnesium precipitate. It's good for the heart, but a nuisance in developer. I use a mixture of 20 Mule Team borax and Red Devil lye with tap water. The ratio is about 1 tsp lye to 1 tbs borax for a liter of working solution. This goes along with a tbs of ascorbic or erythorbic acid and 15 ml of 1% phenidone solution.
     
  6. psvensson

    psvensson Member

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    In my experience with E-76-type developers, sulfite concentration has a very strong effect on activity.
     
  7. psvensson

    psvensson Member

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    Ooops. I did use 2 tbsps carbonate.

    That's interesting. Does ascorbate age faster in solid form or in solution? I guess they ionize the same way in an alkaline solution, so the intuitive answer would be "solid form," but not everything about photo chemistry is intuitive, it seems.

    Does your developer turn pink too? I have used AA as well, but maybe only in the PG and TEA mixtures. Maybe it's worth trying on its own.

    I tried adding more ascorbate, and that did seem to extend life, but only up to a point. And it didn't solve d-max problem.

    It's very strange that results can differ so much!
     
  8. psvensson

    psvensson Member

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    That approximates metaborate, right? I've tried metaborate as the alkali too, but it didn't give a full D-max.
     
  9. Mark Layne

    Mark Layne Member

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    Sodium Ascorbate

    I would like to try adding Sodium Ascorbate to Rodinal.
    Does this masquerade in the supermarket under some common name or does it have to come from a chemical supplier?
    Mark
     
  10. dancqu

    dancqu Member

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    On face a contradiction. What do you suppose could be the reason for that.
    I'd suggest test conditions. Youself and G. Haist might agree with one another
    after testing with the same methods and conditions. You results though may
    be the better news.

    Have you tested at constant ph? Dan
     
  11. titrisol

    titrisol Member

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    Yes, that is what we discussed as Kodalk replacement.

    Re: D-max problem I think you may need to increase the phenidone:ascorbate ratio
    it is definitely a lack of activity
     
  12. gainer

    gainer Subscriber

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    Most of the ascorbates I have seen in health food stores are calcium, which is not of much use in developers because it causes much precipitation. The best way is to use ascorbic acid with baking soda in the ratio of 2 tsp ascorbic acid to 1 tsp of baking soda. This is close enough neutral for government work. Mix it in an ounce or so of water and let the effervescence subside before adding it to the developer solution.
     
  13. gainer

    gainer Subscriber

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    The activity of an ascorbate-phenidone mixture goes UP rapidly from 10:1 to 20:1 and less rapidly from 20:1 to 40:1 as you hold phenidone constant. From 40:1, it continues to increase gradually in activity. The assumption is that you keep pH constant, which will happen if you use sodium ascorbate made as in the previous post. If you take it to the extreme of 0 ascorbate, you will understand the reason why that is true. Phenidone alone is not a contrasty developer, and is not particularly well preserved by sulfite.

    In answer to another question, the pink color is a sign of oxidation of the phenidone. Ascorbate is more of an orange. Increasing the phenidone will not help as much as increasing the ratio of ascorbate to phenidone while making sure that alkalinity is constant. That means if you use ascorbic acid, increase whatever alkali you are using as you increase the ascorbic acid.

    The things you do by habit with MQ or PQ developers are not always profitable in MC or PC. The chemistry of the reactions is different. The product of reduction of silver bromide by ascorbate is dehydroascorbate and HBr with the result that local pH and eventually overall pH rises.
     
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  15. gainer

    gainer Subscriber

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    I forgot to mention that the ratio of lye to borax that I mantioned gives a higher pH than Kodalk.
     
  16. psvensson

    psvensson Member

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    No, I don't have a pH meter. Maybe someone knows approximately how pH will vary with sulfite concentration in a D-76-type developer?
     
  17. Mark Layne

    Mark Layne Member

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    Thanks very much for this tip Pat

    Mark
     
  18. dancqu

    dancqu Member

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    It has no effect then it does have an effect. If you varied the
    amount of sulfite very much it would affect the ph. E-76 has,
    IIRC, 8 grams of ascorbic acid.

    The amount could be I'd think as little as 20 grams and have little
    effect. The activity might even increase with some reduction. That
    due at least in part to the solutions lower ionic strength.

    You've not given any details. Is E-76 more or less active with more
    or less sulfite. Your findings contradict Haist's according to another
    post. Haist is considered quite an authority.
     
  19. psvensson

    psvensson Member

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    More sulfite makes the developer more active. As quoted by Tom, Haist's statement does not make any sense, or at least, is much too far-reaching. My favorite film developer right now is a phenidone-ascorbic formula with sulfite as the only accelerator. Obviously, more sulfite makes it more active.

    Maybe Haist is talking about the fact that sulfite isn't necessary to activate phenidone-ascorbic superadditivity? I don't have the book, so I don't know.
     
  20. psvensson

    psvensson Member

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    Ok, I found some tests I've done that illustrate the effect of sulfite. This is a case where sulfite is not the only accelerant - in fact, the developer works fine without it.

    I exposed a roll of Delta 400 35mm and cut it in three. Each strip was developed in:

    1l water
    0.5 tsp ascorbic acid
    4 ml phenidone/alcohol solution a la Gainer
    20 ml TEA
    9 minutes at 76 F

    Plus added sulfite as follows:
    Strip 1: No sulfite. Contrast 1.14
    Strip 2: 0.5 tsp sulfite. Contrast 1.29
    Strip 3: 2 tsp sulfite. Contrast 1.38

    To me that looks like sulfite has an effect on activity that doesn't spring from its effect on pH, but it's short of conclusive proof.
     
  21. gainer

    gainer Subscriber

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    ANYTHING you add to a developer can have some effect. What I have read is that ascorbate develpers with litle or no sulfite are surface developers, meaning surface of the halide crystal. Surface developers have certain advantages in speed-grain ratio, if you can imagine such a number. When I say that sulfite has no beneficial effect in an ascorbate developer, I refer mostly to the preservative effect, but also I have not seen any beneficial influence on granularity or film speed that you could not obtain without the sulfite. Of course, I haven't seen everything yet. If I make it to Heaven, I'll try to get a message through.
     
  22. Maine-iac

    Maine-iac Member

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    Where did you get this notion? I have kept a 1% Phenidone solution dissolved in alcohol for months and months with no degradation. You must use 90% alcohol rather than the 70% variety, but I mix it up in 100 ml batches, which with my formulas (they call for 4 ml per liter) lasts a long time. I've kept the stock for nearly a year before it's gone off.
     
  23. psvensson

    psvensson Member

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    Results vary. I used 90 percent rubbing alcohol and noticed a reduction in activity after a few months.
     
  24. Tom Hoskinson

    Tom Hoskinson Member

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    I got my notion from my own testing and results reported by Pat Gainer and others.

    I have a bottle (100ml) of 1% Phenidone dissolved in 90% Isopropanol and a 100ml bottle of 1% Phenidone dissolved in technical grade Polyethylene Glycol. I made these two solutions on the same day about a year ago. The alcohol solution has degraded, the Polyethyene Glycol solution has not when compared with fresh solution (all mixed with the same batch of dry Phenidone powder).

    Recall that alcohols in general are water grabbers and Phenidone oxidizes in water. The dryer the alcohol, the longer the stock solution will last.
     
  25. glbeas

    glbeas Member

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    I found some stuff called Fruit Fresh at Wally World which has listed in order, Dextrose,Ascorbic Acid, Citric Acid, Silicon Dioxide. Contains no sulfites. This is for canning and whatever. How well do you think this will work? Anybody know an approximate percentage of ascorbic in this product?
     
  26. dancqu

    dancqu Member

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    "... sulfite is not the only accelerant" So, without the sulfite it must
    be the TEA that makes it go.
    Those "contrast" numbers look to me like maximum negative "densities"
    You've a densitometer but no ph meter?

    According to Patrick Dignan, phenidone works at a lower ph than metol.
    The TEA may make it go some but adding sulfite may very well
    up the ph and activity.

    BTW, the above formula is a long way from E-76. It is though a PC
    developer.

    Have you tried phenidone in bisulfite solution a la Dignan; One gram
    phenidone, 5 grams S. bisulfite, to make one liter? Dan