Phenidon-Ascorbate developer high base fog?

Discussion in 'B&W: Film, Paper, Chemistry' started by grommi, Feb 14, 2013.

  1. grommi

    grommi Member

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    I read Pat Gainers articles on phenidon/ascobate developers and tried to mix my own simple one shot developer. That's what I mixed:

    4 g/l sodium carbonate anhydrous
    4 g/l ascorbic acid (pure)
    0.5 g/l pot. bromide
    0.1 g/l phenidone

    Added in given order. I use stock solutions of phenidone in glycol and bromide in a. dest.

    pH is about 9.5

    I used Pats recommended relation of ascorbic acid / phenidone = 40/1. Negs are of low contrast and underdeveloped, but base fog is very high: 0.68 with HP5+. See graph below, red curve, exposed as Iso 800, real speed about Iso 200 with low gamma, all densities above base fog = 0.68.

    Developed 10 minutes 20 °C, agitation first minute cont., then 3x every 60 sec. If I would increase development time I will get even more base fog. What's wrong here? Is this developer prone to exessive base fog? Any suggestions?

    Best - Reinhold

    test.jpg
     
  2. georgegrosu

    georgegrosu Member

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    I am not familiar with graphs of this type.
    I use diagram density - log H. Probably is a error from write.
    Fog density of 0.68 seems a bit high and not shown on the graph.

    George
     
  3. Gerald C Koch

    Gerald C Koch Member

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    Creating a useful and reliable developer is a very complex endeavor requiring among other thinks a good knowledge of photochemistry. It is not just dumping a bunch of chemicals into water. A point that I agued with PG over and over again. I doubt he ever really got the point of the argument. Check the current thread "Progress on XTOL-concentrate." to see just how difficult the problem is. The thread is now at 48 pages and still very active.
     
  4. michael_r

    michael_r Subscriber

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    Not only the chemistry knowledge, but the ability and equipment required to do proper testing of the formula on films - which is very, very far beyond the means of anyone on APUG past or present. Which is why in all honesty using any formula that has not come out of Kodak or Ilford at this point is mostly guesswork with results based on anectodal evidence at best. By the way that includes Crawley, current staining formulas, and anything else anyone has come up with.

    This won't be a popular opinion of course.
     
  5. albada

    albada Member

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    Reinhold,

    Here's a simple one-shot developer I discovered last year. It uses only three chemicals, and gives quality near-XTOL:
    http://www.apug.org/forums/forum37/99921-pc-sulfite-simple-developer-giving-xtol-quality.html

    As Jerry and Michael R have pointed out, much testing is needed to qualify a developer. I am the person doing the work in the "Progress of XTOL-concentrate" thread. I've restricted myself to using only these chemicals: sodium sulfite, sodium metaborate, ascorbic acid, phenidone/dimezone. All except sulfite are dissolved in propylene glycol. That's a simple developer. But even after experimenting with it for a year, I'm still getting surprises. You should expect surprises. High fog was your first surprise. I assure you there are more. :smile: But I encourage you to experiment. I have made several new discoveries (at least, they are not in the literature). Perhaps you will make a discovery...

    Mark Overton
     
  6. grommi

    grommi Member

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    Thanks a lot, Mark. To be honest, the "Progress on XTOL-concentrate"-thread makes me dizzy and I appreciate your simple PC-Sulfite formula.

    I like simple formulas for a one-shot devloper that I can mix myself. P, C, and S are easily available, many other agents aren't like metaborate and borax or TEA, that are very resticted to buy for private persons where I live. BTW, I have the same P as you with CAS-# 92-43-3. I will try your PCS recipe, if I shouldn't be satisfied I still have my Caffenols :smile: I will report.

    Thanks a lot everybody here at Apug. Best - Reinhold
     
    Last edited by a moderator: Feb 15, 2013
  7. albada

    albada Member

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    Reinhold, I have learned more in the year since I discovered PC-Sulfite. If you decide to mix it, I suggest reducing the Phenidone to 0.10 g/litre. If you try it, could you post a response to that "PC-Sulfite" thread?

    Good luck,

    Mark
     
  8. grommi

    grommi Member

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    "If you try it, could you post a response to that "PC-Sulfite" thread?"

    Yes, I'll do.
     
  9. Patrick Robert James

    Patrick Robert James Subscriber

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    I have been using a Phenidone/AA paper developer off and on for years and I have noticed that it needs a lot of restrainer to keep the whites clean on some papers. I stick with it though because it is easy to make.

    I do seem to recall from my research a few years ago that it is better to use an organic restrainer with Phenidone so I use Benzotriazole not KBr for what that is worth to you. I am not an expert though so maybe someone who is can comment on that.
     
  10. Alan Johnson

    Alan Johnson Subscriber

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  11. grommi

    grommi Member

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    Yep. I always do a clearing test.
     
  12. Zathras

    Zathras Subscriber

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    Hi Reinhold,

    Have you read this article by Patrick Gainer at unblinkingeye.com? Neat the end of the article he shows different variations of the developer in two tables.

    Your formula is not the same as the formula Gainer describes in the article. I think that the main cause of the problem is too much phenidone in the developer. How much dry phenidone are you actually dissolving into a liter of developer? If you are indeed using .1 grams of per liter of developer, then you have 5 times the required amount in your developer. The correct amount is closer to .02 grams per liter. Gainer added 2.5 ml of a phenidone solution to a liter of developer. He made this solution by dissolving .65 gram of phenidone in 80 ml of 90% isopropyl alcohol or denatured alcohol.

    You also have 2 times the required amount of ascorbic acid in the developer. The amount of sodium carbonate anhydrous should be 5 gams per liter. I think that the excess phenidone and ascorbic acid are causing all the trouble.

    I think you would have better results if you mixed the formula as follows;
    Water 20C 750ml
    4 g/l sodium carbonate anhydrous Keep this the same for now, since the quantities of ascorbic acid and phenidone will be reduced.
    2 g/l ascorbic acid (pure)
    2.5 ml phenidone solution
    Water to make 1000ml

    You may find that the potassium bromide is not needed.

    I hope this helps, Post back if you try this, and let us know what the results are.

    Mike
     
    Last edited by a moderator: Feb 16, 2013