Improved pyro-ascorbic developer

Discussion in 'B&W: Film, Paper, Chemistry' started by juan, May 11, 2005.

  1. juan

    juan Subscriber

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    Jay, what is your development temperature? 68F/20C?
    juan
     
  2. Andy Tymon

    Andy Tymon Member

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    Jay,
    have you tried this developer using rotary processing, does the pyrogallol oxidies like pmk does?
     
  3. jim appleyard

    jim appleyard Member

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    Jay, you are truly an evil scientist!!! You gotta slow down, man. You come up with new formulas faster than I can use up all my old chemistry (maybe that should tell me that I need to shoot more). Anyway, I'll be happy to put this on the list as well as the others. Thanks, Jim
     
  4. nze

    nze Member

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    How long does the concentrated keep . I' am new to TEA developer and I am wuite surprised to hear that pyro can be mixed with an alkali and without any oxidation
     
  5. Tom Hoskinson

    Tom Hoskinson Member

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    The TEA concentrate should keep for a very long time, in my experience.

    TEA does not act as the alkali until water is added to the concentrate.
     
  6. nze

    nze Member

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  7. Loose Gravel

    Loose Gravel Member

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    Jay, I'd be interested in the HP5+. I'm wondering, since I don't have TEA on my shelf, if I can just mix a small amount and give it a try. As I understand it, TEA is inert and only suspends the chemicals for easy dilution. ?
     
  8. nze

    nze Member

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    Jay,

    How does look the negative compare to a pmk one. Is there a green secondary image or not*????
     
  9. nze

    nze Member

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    I should give this developper a try. I will order some tea and keep you inform of my result with kodak film and platinum print.

    Best,
     
  10. Tom Hoskinson

    Tom Hoskinson Member

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    Actually, TEA performs two roles: It acts as the solvent for the chemicals in question and it also provides the alkali when diluted with water.

    I live just down the road in Thousand Oaks and I have a gallon jug of TEA. PM me and I'll mail you enough TEA to try it out.
     
  11. jim appleyard

    jim appleyard Member

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    Jay, are there any time or temp changes if using carbonate instead of TEA?

    BTW, I hope you realize that I was only pulling your leg with the evil scientist/slow down stuff. I really do appreciate the time and effort you've put into your formulas and your generosity in sharing them. Jim
     
  12. Loose Gravel

    Loose Gravel Member

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    I've not used TEA before, but I guess I will be soon. Is its freezing point a problem? When the developer is mixed, what is the freezing point then?
     
  13. Lee L

    Lee L Member

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    Jay,

    I, for one would appreciate your posting all that info. I know your results are really just a starting point for any other given photographer, but a place to start is always nice.

    Thanks,
    Lee
     
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  15. Photo Engineer

    Photo Engineer Subscriber

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    Jay, ruling out reading error, the bumps in that curve you posted are indicative of an anomaly. It may be that the blended emulsions in the film are not developing properly or that there is a change in tone of the silver and / or the stained image.

    I would warrant that a piece of that film processed in a 'standard' developer such as HC110 or D-76 would not have that bump.

    Whether this is a problem or just plain unimportant should be determined by the user after careful examination of the prints. But, it just cannot be ignored. It would be nice if you posted a comparison with some standard.

    PE
     
  16. fhovie

    fhovie Subscriber

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    I am already using PC-TEA - Other than images stain, can I expect any other differences? I was hoping PC-TEA would be as smooth as XTOL and it was not. I guess the lack of Sodium Sulfite will do that. I am very pleased with the results of Pyrocat - and had many happy years with PMK (although the grain was too big) I am wondering if this replaces PC-TEA as an improvement and if This will maky XTOL unneccesary.
     
  17. Kirk Keyes

    Kirk Keyes Member

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    If all Jay's film show this kind of behaviour in the graphs, it may indicate that the step wedge that he is using is not evenly spaced, causing the point to be misgraphed. (Not that this is really a problem, it is just that he needs to take it into account in the graphing of the points.) It may be a reading error on the x-axis, not the y-axis...

    Maybe it is not so much a hump in the Zone V region as the dip at Zone IX that is causing the concern of PE? Again, it could be caused by a mismatch of the step wedge and the plotting software defaults.

    Jay, does that web app that you are plotting with let you input the values for your step wedge, or are you forced to use the Zone step points that it shows on the x-axis?

    Kirk - www.keyesphoto.com
     
  18. sanking

    sanking Member

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    You say that for roughly equivalent dilutions 510-Pyro is much more active than Pyrocat-HD. I don't see it.

    In the curve you show for the development of HP5+ you have a negative density range of .025 - 1.74 with the 1:100 dilution, at six minutes of develoment at 70ºF, with constant agitation.

    I just looked at my development of HP5+ in Pyrocat-HD. At the same development temperature and constant agitation here is what my tests gave with the 2:2:100.

    5 minutes .12 - 1.56
    7 minutes .12 - 1.87

    Adding the additional B+F of 0.13 that you are getting with your film/developer combination (which I assume is caused by the higher B+F of the film itelf?) these DRs would be .25 - 1.69 (five minutes) and .25 - 2.00 (seven minutes). In other words, based on these results it appears to me that Pyrocat-HD is at least as active as 510-Pyro, if not slightly more so.

    So where am I going wrong?


    Sandy
     
    Last edited by a moderator: May 14, 2005
  19. Kirk Keyes

    Kirk Keyes Member

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    Sandy - you're using sheet film, right? I think Jay said he was using 220 roll film. That's probably the difference where the differnce in base densities comes from.

    The Pyrocat and 510-Pyro look to be pretty close in "activity". His developer was at a 100 times dilution for his run, yours was at 25 times (2+2=4 parts in to 100). So Pyrocat used more stock solution to get to the same ballpark. Of course, we could go and calculate on total amounts of materials in the final dilution and not worry about dilution amounts.

    Or, maybe Jay should test it a 1+90 dilution to get the activity crown.
     
  20. sanking

    sanking Member

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    Yes, I gathered that Jay was using either 35mm or roll film to test and assume that accounts for the considerable difference in B+F in our tests.

    Regarding the second point, I normally am only interested in comparing the actual amount of reducer (s) in the working formula, and if memory serves Jay usually does it that way as well. So we would be looking first at the total amount of pyrogallol + ascorbic acid + phenidone in a liter of working 510-Pyro, against the total amount of pyrocatechin + phenidone in Pyrocat-HD. Comparison of the dilution itself by itself is meaningless since the stock solutions don't have equivalent amounts of reducers.

    I should also add that the addition of a very small amount of ascorbic acid to the Pyrocat-HD formula provides a significant boost in energy. In fact, I describe a formula called Pyrocat+ on the AZO forum that takes advantage of ascorbic acid to provide this extra boost. The amount is almost miniscule, amounting to about 10ml of a 1% solution of ascorbic acid per liter of working solution, which is 0.01 g of ascorbic acid per liter, if my calculations are right.

    However, I am also beginning to think that we may need to re-consider the description of a high-definition developer. Typically the description of a high definition developer is one that contains a very low amount of sulphite, so as to prevent grain solvent action, and around 1.0 g per liter or less of reducer. However, when talking about these high energy formulas that result from the additional synergism between two or more reducers that are super-additive I don't think that the concept of 1.0 g or less of reducer per liter is valid. These solutions re-generate so effectively that in essence they limit the production of adjacency effects because it becomes very hard to get any local exhaustion of the developer, at least with normal and constant agitation. What this means is that the method of development, i.e. type of agitation, becomes highly important with this class of developers if our objective is maximum apparent sharpness through adjacency effects.

    Sandy
     
    Last edited by a moderator: May 13, 2005
  21. Kirk Keyes

    Kirk Keyes Member

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    Yes - the affect of superaditivity, and then the combinations of more than two developing agents makes this all kind of like a numbers game when trying to determine "activity" levels.

    Perhaps we should just compare $/L of developing agent instead of total grams/L would be more interesting.
     
  22. sanking

    sanking Member

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    Jay,

    Yes, I am much too busy with others things right now to be doing any film testing, but I have dozens and dozens, if not hundreds of files of tests with many film/developer combinations that serve as reference that I can look at without actually doing any further testing.

    Your comparison of my results with FP4+ in Pyrocat-HD 5:3:1 with your results with HP5+ in 510 Pyro is not a good one for several reasons, but most importantly because in my test of Ilford FP4+ with the 5:3:1 dilution the film actually reached gamma infinity at a time of slightly more than seven minutes. In other words, no additional contrast was obtained after eight minutes of development so the twelve minute time mentioned is something of a canard.

    As of this point I have not done any serious comparison between Pyrocat-HD and Pyrocat+ to see if there is any difference in sharpness. However, what I can say for sure is that there is for sure an increase in sharpness of Pyrocat-HD negatives processes with minimal and semi-stand agitation in comparison to those processed with rotary (constant) agitation. Which is why I stated earlier that the method of processing with this class of developer is probably much more important than the formula itself if maximum apparent sharpness is the objective.

    You are of course right in that the ultimate quality of a high definition developer is that it produces maximum apparent sharpness.

    BTW, I am pleased to see the reduction in the amount of phenidone in your 510 Pyro compared to some of your previous developers, since having too much of this reducer causes more loss of sharpness (because of the tremendous regenerative quality of phenidone) than a mild excess of one of the other reducers. At some level of agitation I consider it highly likely that the reduction in phenidone will have a positive effect on apparent sharpness.



    Sandy
     
    Last edited by a moderator: May 13, 2005
  23. sanking

    sanking Member

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    Jay,

    My first impression of the comparison data did not suggest the magnitude of difference in activity between the 510-Pyro and Pyrocat-HD that you show above. I wonder if there is not some type of anomaly in your graphing program? For one thing, the axis for Pyrocat-HD seems shifted up (suggesting over exposure) about one full stop relative to the 510-Pyro axis. This would explain, at least in part, the higher maximum density of Pyrocat-HD. I think that if you run these tests again, adjusting exposure, you will find that the energy level of 510-Pyro and Pyrocat-HD is much closer than your initial results indicate.

    Sandy
     
  24. sanking

    sanking Member

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    Sorry Jay, but you are simply wrong and there are no ifs, ands and buts about it. Something is very much off at your place. Pyrocat-HD produces very low B+F levels, as low as developers such as D76 and Xtol. If you are getting B+F of .46 in blue channel mode with HP5 developed in Pyrocat-HD, at the CI levels in question, then something is wrong with your procedures, either with the way you mixed Pyrocat-HD, or or with your sensitometer, or with some other aspect of your work.

    Sandy
     
  25. sanking

    sanking Member

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    Jay,

    That would be in order.

    Just for the record, one of the main reasons that Pyrocat-HD became very popular with many alternative printers is because it gives very low B+F levels, compared to other pyro developers, with UV sensitve processes, even with development to very high CI. Blue channel B+F levels are *even* lower, usually on a par with non-staining developers.

    No way Pyrocat-HD should give B+F levels of the magnitude you suggest. If it did, there would be very few people using it.

    Sandy
     
    Last edited by a moderator: May 14, 2005
  26. sanking

    sanking Member

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    The B+F still seems higher than it should be. How are you measuring the potassium bromide? If you are mixing the Pyrocat-HD stock solution in small amount the accuracy of your weighing is a very important issue. It is pretty difficult to accurately measure 0.2 g for the 100ml stock.

    A better way would be to mix up a stock solution of bromide, say abourt 10%, and then add the amount to the Stock A solution.

    I mention this because the difference between 1.5 g and 2.5 g in a liter of Stock Solution A makes a very big difference in B+F and EFS.

    Sandy