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  1. #11
    c6h6o3's Avatar
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    Quote Originally Posted by jdef
    Hypercat works really well for me.
    Does 510 have ascorbate in it?

  2. #12

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    Jay,

    The difference in stain with the addition of ascorbic acid between Hypercat and Pyrocat-HD is IMHO due to the difference in pH of the working solutions. Pyrocat-HD is working at a pH of about 10.9 while the pH of Hypercat is well over 12.

    Bromide does not afffect stain, and the sulfite does in the Pyrocat-HD formula is far below the critical amount where it begins to reduce stain.

    Sandy


    Quote Originally Posted by jdef
    Hypercat works really well for me. Hypercat contains more ascorbic acid than you guys are using, but contains no sulfite or bromide, which I think makes the difference. There is certainly no loss of stain with Hypercat compared to Pyrocat HD. I think the Pyro-glycin-TEA developer I'm testing might also be useful for this kind of technique.

    Jay

  3. #13

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    I've been using pyrocat-hd at 1.5:1:200 for semistand with fp-4 and the negs just make me wanna squirt. The micro contrast in an Azo print is somthing that has to be seen to behold. I can't imagine going back to regular agitation, unless I was shooting for the quality of say, newsprint.

  4. #14
    c6h6o3's Avatar
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    Quote Originally Posted by jdef
    According to Gordon Hutchings, 510-Pyro, which contasins both ascorbic acid and phenidone shouldn't produce very sharp negs
    I'll have some of whatever he's been smoking...

  5. #15

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    i processed some foggy tmax400 120 film last weekend using semi-stand developement ... 2 rolls, probably the best roll film i have processed in years. i used 73º ansco130 1:10 for 24 mins and inverted the tank 4 times at 15 mins, 20 mins and 23mins.


    clay recently published the formula for mortenson's glycin varient ( here ) and i am going to do the same thing with that stuff and see what happens.

    -john

  6. #16
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    Quote Originally Posted by jdef
    Jim,

    you break it up, and I'll twist it up. Have you printed your TMY/510-Pyro negs?


    Jay
    ...not in amidol, but the proof I developed in Neutol is excellent. A lot more contrast than I would've thought. This is the only developer I've ever used on TMax which yields a green image stain. It looks a lot like Efke or Ilford films in ABC, but cleaner. Not much general stain at all.

    Tonight I think I'm going to try one using Steve's semi-stand method. (It's the one made at the monastery, Steve. The TMax dupe of the Efke one I ruined in the workshop. I rated it at 200, so I'll be sure to back off considerably on the development.)

  7. #17
    c6h6o3's Avatar
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    Quote Originally Posted by jdef
    Jim,

    I use 510-Pyro with reduced agitation for Freestyle APHS Ortho film, at 1:500 for 20min, with one inversion at 1/3 and another at 2/3 dev. time. Works great. Andre` de Avillez has used the same, or similar technique with good results. I haven't tested the technique with TMY, so I can't recommend times or dilutions. Good luck.
    Wow. 1:500. Sounds awfully dilute. That doesn't seem to work with Pyrocat very well, but maybe 510 is different.

    I think maybe I'll test with some 4 x 5 film first. I have a lot of it.

  8. #18

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    Just measure th pH of a working solution of Hypercat and you will ifind that it is well over pH 12, about 12.4 or so from my tests.

    Of course, my measuring instruments could be wrong, but they appear to be working ok because when I measure the pH of other developers, PMK for example, my measurments of pH 9.5 to 9.7 turn out to be very close to to the 9.6 that Hutchings reports.

    It is certain that the combination of even small amounts of sulfite and ascorbic will kill the stain with pyrocatechin developers, unlike pyrogallol types which are obviously more resistant. However, what I am suggesteing is that the pyrocatechin based developer will allow much more ascorbic and/or sulphite without losing the stain if it is working at a higher pH.


    Sandy


    Quote Originally Posted by jdef
    Sandy,

    I don't think the pH of Hypercat is as high as you say. Ascorbic acid is about 10X more acidic than sodium metabisulfite, and neutralizes some of the sodium hydroxide in the working solution to form sodium ascorbate, so the pH of the working solution is not the same as the pH of the B solution alone. In any case, I've tested it using the B solution of Pyrocat HD with no significant difference in stain formation, maybe because potassium carbonate has a much higher buffer capacity than the weak solution of sodium hydroxide used with Hypercat, and is less sensitive to the addition of ascorbic acid. The sodium metabisulfite in Pyrocat HD might not reduce the stain appreciably, but when you start adding ascorbic acid, it doesn't take much before you'll see stain loss because of its addition with the metabisulfite. There is as much sodium metabisulfite in Pyrocat HD as there is ascorbic acid in Hypercat. If I was to add sodium metabisulfite to Hypercat, it wouldn't take much to begin to reduce the stain formation. I think that using both is redundant.

    Jay

  9. #19

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    Jay,

    I missed the part about using Hypercat with the Pyrocat-HD stock solution so guess you are right about the pH not having a role in the stain.

    My own tests do confirm that the amount of phenidone in the Pyrocat-HD formula is more than needs to be there, and the same is true of potassium bromide. I will most likely amend the formula at some point in the future, though from a practcial consideration there is not much to be gained but perhaps a slight increase in EFS.

    BTW, my use of sodium metabisulfite over sodium sulphite has nothing to do with a desire to decrease the pH of the working solution. The metabisulfite is there to provide stability for the stock solution when mixed with water. For mixture in glycoal the sulpite can be eliminated, with just a very slight loss of energy. However, for many reasons I intend to promote the use of Pyrocat-HD primarily for mixture with water in stock solutions, where is has pretty impressive stability -- at least a year or more. Mixture in glycoal does offer some advantages, both in terms of stability and choice of ingredients, but so to does the convenience of mixture in water.

    As for edge effects, there may be advantages to working solutions that are poorly buffered, but there are also disadvantages. With Pyrocat-HD adjacency effects are determined by type of agitation, and the working solution is well-buffered up to dilutions of about 2:1:400.

    Sandy


    Quote Originally Posted by jdef
    Hi Sandy.


    Your hypothesis ignores the fact that Hypercat still produces very high stain when used with the Potassium carbonate B solution of Pyrocat HD. I would guess that the pH of the Hypercat A/ Pyrocat B solution would be lower than the pH of Pyrocat-HD. If the difference in the pH levels of the working solutions of Hypercat and Pyrocat HD was responsible for Hypercat's tolerance of its much greater ascorbic acid content, I would expect to see much reduced stain formation when using a working solution made up of Hypercat A/Pyrocat B. It seems clear to me that the presence of sodium metabisulfite reduces the pH of a working solution of Pyrocat HD, and the addition of ascorbic acid would reduce it further, which, beyond a certain point, could impact stain formation. According to your own tests, that point is fairly low. I would expect the same, or similar result by adding sodium metabisulfite to Hypercat. If I wanted to increase the energy of hypercat, I would substitute some of the ascorbic acid for sodium sulfite, which would activate the catechol/phenidone pair, but Hypercat is energetic enough as-is, and the addition of sulfite would require much higher mixing temps, and generally compromise the formula, I think. Adding sulfite to the working solution wouldn't work very well, because the ascorbic acid is scaled to reduce general stain to zero, and the addition of even a small anount of sulfite would impact stain formation, just as the addition of a smal anount of ascorbic acid to Pyrocat HD impacts stain formation.

    For all their similarities, it is the differences between Pyrocat HD and Hypercat that fascinate me. Pyrocat HD depends on the catalytic action of the sulfite ion on the catechol/phenidone pair for its activity, while Hypercat relies more heavily on the ascorbic acid/phenidone pair, lacking any form of sulfite to activate the phenidone/catechol pair. I suspect that like it's close cousin, phenidone/hydroquinone, the developer product of the phenidone/catechol pair is itself a developer, possibly more active than the catechol itself, while the product of the ascorbic acid/phenidone pair is weakly acid and retards development. The choice of restrainer/antifoggant is also interesting. Pyrocat HD uses KBr, and Hypercat, BZT. Thes agents also work in completely different ways. KBr retards development, and reduces contrast and film speed, while BZT works much more selectively, having no effect on the progress of development, which might be why Pyrocat HD needs 60% more phenidone than Hypercat uses. Then there's the choice of alkali. Since both developers use separate alkali solutions, it's very easy to isolate the effect of the alkali in testing, by substitution. I should rephrase, it's easy to test the obvious effects of the alkali, such as activity and stain formation, by substitution. I believe that the choice of alkali also has an important effect on the formation of adjacency effects, but while that seems obvious enough, it's very difficult to quantify, and even more difficult to ascribe the difference to the choice of alkali. The conventional wisdom has always been that a strong solution of a weak alkali is to be preferred to a weak solution of a strong alkali, for robust and constant working properties, but the formation of edge effects depends on the local exhaustion of the developer, which is much enhanced by a weak solution of strong alkali. It's all very fascinating.

    Back to the subject, it seems that if one was interested in adding ascorbic acid to Pyrocat HD, one should consider substituting sodium sulfite for a part, or all of the sodium metabisulfite in the Pyrocat HD formula. This substitution would negate the pH reduction effect of the addition of ascorbic acid with its attendant reduction in stain formation, while maximizing the energy of the developer. If the reason for specifying sodium metabisulfite over sodium sulfite is to decrease the pH of the working solution, it seems to me that the same thing could be accomplished by the scaling of the alkali, as Steve Sherman suggests above. I think that the high phenidone content of Pyrocat HD is a prime contributor to fog, and only needed to offset the effect of KBr, which is added to control fog. A real catch 22.

    Jay
    Last edited by sanking; 01-27-2006 at 05:45 PM. Click to view previous post history.

  10. #20
    c6h6o3's Avatar
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    Jay:

    I developed a negative tonight in 510 at 1:200 using a semi-stand regimen. 4 periods of 10 minutes each at 72 degrees F. Gorgeous. Image stain out the wazoo and very clean. It looks a little thin, but then again so do some of Steve's and there is beau coups stain so it may print with a surprising amount of contrast. I have another one to do tomorrow night and then I'll proof them both on Sunday. Stay tuned. It looks like 40 minutes or so is the time for a normal TMax negative (SBR 7).

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