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  1. #1

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    Pyro / Catechol paper devs

    Hi,

    I have seen a few refernces to these PAPER devs here and there and would like to know more about their qualities with regard to image characteristics. Dont you find messing about with prints sloshing about in trays with pyro a little scary! I am happy when it is locked in a tank, but we have all had a bit of splashback in paper processing. Are the concentrations lower for print pyro type devs? Most of all, do the prints look 'different' and if so, how? Do they have any sort of compensating effect up the scale as in the neg devs??

    Cheers Tom

  2. #2

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    Tom, all my AZO contacts are developed using a catechol paper dev and Neutol WA. Lovely tonal rendition and control of highlights. I would characterize it as mid- to high contrast in effect, which is why it typically is the second dunk in my procedures. I love it with AZO. As far as I am concerned it beats my Amidol developed prints and is more convenient - I no longer need to have powdered chemicals around the house as they come in a liquid kit form.

    I always use Nitrile gloves and I do not slosh my prints in the trays - I use my gloved hands to make sure the paper is under water and then I leave them lying there until their time is up.
    Francesco

  3. #3

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    All developing chemistry should be handled with good chemical safety practices in place. Skin protection (I use nitrile gloves) is essential. Chemical dust and vapor is hazardous and thus must not be inhaled. Respirators or vented chemical hoods may be required for some mixing processes. Safety glasses may also be required.

    Pyrogallol (1,2,3-Trihydroxybenzene), Hydroquinone(1,4-dihydroxybenzene) and Pyrocatechol (1,2-dihydroxybenzene) are very closely related benzene ring developing reagents. They are all toxic. In low (or no) sulfite solutions, they are all capable of staining the image and proportionally tanning the emulsion gelatin.

    All of these reagents are used in both film and paper developing formulations. A very familiar formulation is Kodak Dektol (Metol/Hydroquinone).

    I (and others) have been testing Donald Miller's PPPD (Pyrogallol, Pyrocatechol, Phenidone Developer) paper developing formulation.

    ------------------------------

    43 gm Sodium Sulfite
    .3 gm Phenidone
    10 gm Pyrocatechol
    5 gm Pyrogallol
    50 gm Sodium Carbonate
    3.5 gm Potassium Bromide
    Water to make 1 liter

    Dilute 1-1 to make 2 liter of use solution

    The phenidone should be dissolved in alcohol just as in the Pyrocat formula
    As in all cases where exposure to Pyrogallol is involved, eye protection, nitrile gloves, and respirator should be worn. (Just as in any pyro formulation).

    I am looking for alternatives to Amidol for developing Azo contact prints. Search APUG for PPPD and Amidol.
    Tom Hoskinson
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  4. #4

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    Why are you looking for alternatives to amidol; Different look?

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    Convenience (I do not need to have powdered chems around the house and no longer need to be mixing powdered chems every time I print) and look. Definitely the look!
    Francesco

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    Quote Originally Posted by Francesco
    Convenience (I do not need to have powdered chems around the house and no longer need to be mixing powdered chems every time I print) and look. Definitely the look!
    Tom, my reasons are the same as Francesco's.

    I have componded all the components of PPPD as long shelf life stock concentrates.

    I have also succeeded in compounding a concentrated Amidol stock solution (I made a new batch Friday). I dissolved 24 grams of Amidol in 1 liter of hot (220 F) Propylene Glycol. This was done under a vented chemical hood with a hotplate/magnetic stirring bar combination.
    Tom Hoskinson
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  7. #7
    Silverpixels5's Avatar
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    I used Don's PPPD developer this last week with very good results. It was a bit too contrasty for my Azo negatives, but printed (enlarged from 6x6) with excellent results on some 10+ yr old Oriental New Seagul Select VCFB paper that I have. I have a negative of mine that would always blow the highlights out on paper(with Ansco 130 or Neutol WA), and with this developer I was able to get detail back in them, as well as a wonderful depth to the photograph. In order to cut the contrast down for Azo, I'll be leaving the pyro out and just go with straight catechol. I still love Ansco 130 both for its tonality and its VERY long shelf life, but I imagine I'll use the PPPD for final enlarged prints. For final Azo prints I plan on using Michael's Amidol formula. I still havn't tried it yet because I don't have enough prints to run through it in order to make the high price worth it....can't mix it up and only put out 5 prints....
    RL Foley

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    Quote Originally Posted by Silverpixels5
    I used Don's PPPD developer this last week with very good results. It was a bit too contrasty for my Azo negatives....
    That is an interesting result. My experience with PPPD is that it gave me fairly low contrast on the current lot of Grade 2 Azo (compared to MS Amidol and Ansco 130).

    I started with no KBr in the working developer. It gave me close to a grade 2, and very warm tones - with the Dmax going a bit red. I then added some 10% KBr (twice as much as Don recommended - I goofed) and the developer activity slowed way down. The image tone shifted to blue/black and the contrast dropped to between Grade 1 and 1.5.

    I think contrast and tone control is possible by fine tuning the KBr ratio and by increasing/decreasing the dilution.
    Tom Hoskinson
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  9. #9
    Silverpixels5's Avatar
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    There seem to be two differences in our materials. 1) I have the old lot of Azo...before the plant change, and 2) I used Don's formula as written, but with 4 grams of Citric Acid to prolong tray life. With the Seagul I got very nice, slight warm tones...and its a cold tone paper as far as I know. I toned them in selenium 1:3 and they went back cold. The Azo developed to a neutral --> slight cold tone.....its kind of hard to tell. Now for one, my negative may have been bit too contrasty since I usually tend to go slightly over in my development of them. I don't know for sure though b/c I don't own a densitometer. I think next time I use the developer, I will have one tray with all catechol and no pyro, and the other with the formula you experimented with. I'm sure one will give me the print that I like from the negative, and work well as a soft developer. If you have any more trials with this developer or various combinations of it, please post your results. Thanks!
    RL Foley

  10. #10
    David A. Goldfarb's Avatar
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    Regarding the cost of Michael Smith's amidol formula--what I've taken to doing when I don't have a lot of Azo prints to make is that I run the Azo prints first, then add the appropriate amount of KBr and benzotriazole to the amidol to run enlargements in it, mostly on Cachet/Maco Expo RF, which looks really nice in amidol.

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