Article on Pyro Developers

[chrisl]

Thanks Sandy, I'll give it a try. Hopefully my unidrum roller goes relatively the same speed as the jobo's slow speed you mentioned. And I'll go track down some sodium metaborate as all I have is sodium hydroxide here. Thanks for the tip.

Boy, the times for films are alot shorter for both fp4 and trix comparing pmk to pyrocat (for N dev. I've found online for pmk that is). Nice plus.

Thanks again for the help
Chris

 

[lee]

Sandy,
thats England for you.


lee\c

 

[sanking]

Thanks Sandy, I'll give it a try. Hopefully my unidrum roller goes relatively the same speed as the jobo's slow speed you mentioned. And I'll go track down some sodium metaborate as all I have is sodium hydroxide here. Thanks for the tip.

Boy, the times for films are alot shorter for both fp4 and trix comparing pmk to pyrocat (for N dev. I've found online for pmk that is). Nice plus.

Hi Chris,

Sodium hydroxide is very alkaline. I think that you could add just a bit of it, say 1/4 of a teaspoonful per liter, in substituion of the sodium metaborate or sodium carbonate. Mind you I have never done this but it will definitely make the pre-soak water alkaline and I don't *think* that it will do anything to interfere with the PMK.

And yes, times for Pyrocat-HD are quite a bit shorter than PMK, plus the fact that with the 1:1:100 dilution you get the slight increase in effective film speed.

Sandy
\

 

[john_s]

In this neck of the woods (Australia) isopropyl alcohol is not available at pharmacies. What is readily available is Methylated Spirit which is mostly ethyl alcohol plus some denaturants to make you not want to drink it (typically methyl alcohol, a ketone, and denatonium benzoate whatever that is.)

I think it's the same as Denatured Alcohol sold in other countries.

Would this be a reasonable substitute for isopropyl alcohol? A post that I read somewhere suggested cheap vodka as a substitute. Would it be impossible to get the phenidone to dissolve without any alcohol?

 

[Bulent Ozgoren]

Sandy
Thank you for this excellent article and for your contribution to the photographic community. At one time you have recommended adding 0.5 g of EDTA to 100 ml of both solution A and B. This does not appear in the formula you have now posted. I use distilled water in both stock and working solutions. Would EDTA be necessary when tap water is used? Bulent Ozgoren Istanbul Turkey

 

[juan]

I disolved the phenidone without alcohol - it took a very long time - probably 15-minutes of stirring for just that chemical alone. It can be done, but I'll be looking for alcohol next time.
juan

 

[sanking]

Sandy
Thank you for this excellent article and for your contribution to the photographic community. At one time you have recommended adding 0.5 g of EDTA to 100 ml of both solution A and B. This does not appear in the formula you have now posted. I use distilled water in both stock and working solutions. Would EDTA be necessary when tap water is used? Bulent Ozgoren Istanbul Turkey

OK, about the EDTA. After I made the recommendation to add EDTA to Stock Solutions A and B I received some negative reports from people who actually did this. What they told me was that EDTA killed the working solution. This really puzzled me because in my own work the addition of EDTA worked just fine. But then I remembered that there are two kinds of EDTA, Tetrasodium which is alkaline, and Disodium, which is acidic. Turns out that if you add the Disodium version to Stock B the solution will turn acidic within a relatively short time and the solution will be worthless.

There is no need for EDTA at all if you use distilled water for both the stock and working solutions, *and the pre-soak*. If you use tap water the addition of a small amount of EDTA, Tetrasodium, still makes sense. However, I am not going to put it back in the formula out of fear of folks confusing the two kinds.

 

[sanking]

In this neck of the woods (Australia) isopropyl alcohol is not available at pharmacies. What is readily available is Methylated Spirit which is mostly ethyl alcohol plus some denaturants to make you not want to drink it (typically methyl alcohol, a ketone, and denatonium benzoate whatever that is.)


Would this be a reasonable substitute for isopropyl alcohol? A post that I read somewhere suggested cheap vodka as a substitute. Would it be impossible to get the phenidone to dissolve without any alcohol?

First, the phenidone will dissolve without alcohol but it takes a long time, as a previous message confirms.

Second, any spirit should work fine for dissolving phenidone, the purer the better. Until someone tells me better my view is that any of the alcohols, in whatever form, will do the trick. Vodka should work fine because it is very pure, as should methyl alcohol and denatured alcohol. I am less sure about some of the aromatic spirits, such as gin, tequila, etc. But if they don't work just take a couple of swigs and try again. (Well, don't do that with the methyl alcohol and denatured alcohol, but should work fine with gin, tequila and vodka.)

 

[philldresser]

Sandy
My wife say that if I drink the phenidone cocktail I might get over developed!
Phill

 

[Donald Miller]

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[john_s]

I've located some 95% ethyl alcohol (food grade). I'm interested in making a stock solution of phenidone in alcohol because I don't have weighing equipment accurate enough to measure the small quantities in which phenidone is usually used.

Presumably the more concentrated the better the keeping. Does anyone know how soluble phenidone is in alcohol, and how long would a concentrated solution last without noticeable degradation?

 

[Francesco]

Sandy,

Is it possible to mix the working solution and keep it in a beaker for several hours? I only develope one BTZS tube at a time but I have several of them. Could the working solution stay in a beaker for at least 7 hours? Or is it essential to mix just before use each time?

 

[sanking]

Sandy,

Is it possible to mix the working solution and keep it in a beaker for several hours? I only develope one BTZS tube at a time but I have several of them. Could the working solution stay in a beaker for at least 7 hours? Or is it essential to mix just before use each time?

Francesco,

Frankly I have never tested the concept and the most I have ever delayed before using a mixed working solution is about an hour. However, I think that the color of the solution could be a guide. Once it starts to turn brown oxidation has already set in and your results would be affected. So long as the solution remains very pale amber I suspect that it would be okay.

 

[doughowk]

My only experience with Pyro HD extended over a 12 hr period with good results. In between sessions did store in nearly full & capped container.

 

[fhovie]

How different is Pyrocat from Dixactol monobath? It is my favorite for MF and I am considering giving Pyrocat a try as an alternative to PMK. I noticed Dixactol seems to have all the advantages of PMK with finer grain and greater highlight clamping. If Pyrocat gives me the same results - It is certainly much cheaper to make and the accutance is every bit as good as the PMK.

 

[Jorge]

Is a very different formulation, Sandy uses catehcol and phenidone, Thorton uses catechol, glycin and phenidone I beleive. Of course the mayor difference is price...I think you will be pleased with Pyrocat HD.

 

[sanking]

Is a very different formulation, Sandy uses catehcol and phenidone, Thorton uses catechol, glycin and phenidone I beleive. Of course the mayor difference is price...I think you will be pleased with Pyrocat HD.

I hope to address here the last two message by Frank and Jorge.

First, for Frank. I have never run any real tests on the DiXactol formula so can not say how it compares to Pyrocat-HD. I develped about 20-30 sheets of 4X5 film in DiXactol a few years ago but not with the air of comparing it to another developer. What I can tell you is that the brownish color stain is very similar to what you get with Pyrocat-HD. I quickly lost interest in DiXactol because it is not energetic enough for my needs, which as you know is primarily alternative printing. Development times to get the needed CI for carbon or kallitype printing would be much too long for my taste with DiXactol.

Jorge, with regard to the formula. Fact is I don't know exactly what is in DiXactol since it is a proprietary formula and Thornton has not released the ingredients. However, from reading Thornton's recent article in PhotoTechniques I gather that the original DiXactol formula consisted of pyrocatechin and glycin, not phenidone. The last Thornton formula, Exactol, contains pyrocatechin and phenidone, and perhaps also glycin. Note also that Thornton's mixture for the working solution of Exactol is 1:1:100, exactly same as Pyrocat-HD.

I will add that several years ago I experimented with the addition of glycin in varying amounts to the Pyrocat-HD formula but did not find that anything was gained.

 

[Jorge]

I agree Sandy, I have Thorntorn's book the "edge of drakness" and I seem to recall he mentions using glycin, catechol and phenidone, but like you I am guessing.

 

[john_s]

I used Pyrocat-HD for the first time yesterday, using 2+2+100 on 120 size HP5+. Using the graph in Sandy's new documentation I aimed at gamma=.5 for VC paper. I found the results quite contrasty.

Is there a reason that in the massive amount of info that Sandy has produced and generously presented to us, there is no graph for HP5+ at 100+1+1 dilution? Obviously long development times might be an issue for some people, but an extra 5min would not bother me.

Also, is there any data for temperature compensation for those of us who are fixated at 20degC? I used the published PMK factors for HP5+ that must be fairly relevant.

 

[Donald Miller]

000.

 

[sanking]

I

Is there a reason that in the massive amount of info that Sandy has produced and generously presented to us, there is no graph for HP5+ at 100+1+1 dilution? Obviously long development times might be an issue for some people, but an extra 5min would not bother me.



Yes, there is a reason. In fact two reasons.

First, I am primarily an alternative printer and for my own work use almost exclusively the 2:2:100 dilution. For the broader benefit of Pyrocat-HD users I have done some testing with the 1:1:100 dilution but not nearly so much as with the 2:2:100 dilution.

Second, every single one of the CI charts provided represents at least 3-4 hours of time. This includes:

1. Exposing five sheets of film for exactly the same time to a 21-point step wedge.
2. Developing each of the sheets of film for a different time (calculated from about 0.5X normal to 2X normal, assuring temperature control of +/- 0.5 degrees for all stages of processing.
3. Reading the densities of each of the five sheets at all 21 points of the step wedge. (5X21 readings = 105 total) Different readings are required for silver papers/AZO (Blue reading) and alternative processes (UV reading).
4. Entering the data into WinPlotter. (5X21 entries = 105 total)
5. Analysis of the curves and transfer of the graphics from WinPlotter to PhotoShop to Word.

As you can see, providing useful testing information takes a lot of time. If there are other WinPlotter users who would be interested in running tests and sharing the data for films (and/or dilution) that are not covered in the article I would be very interested in including CI charts of these tests, with credits.

Sandy

 

[john_s]

First of all, film shot for enlarging is never developed in Pyrocat at a 2-2-100 dilution. The 2-2-100 dilution is for negatives designed for alternative process or Azo. That explains why your negatives are contrasty. If you take the 2-2-100 time on the blue channel reading of HP5 and use the same amount of time but cut the dilution to 1-1-100 you should be fairly close.

Thanks. I have been aware of Pyrocat-HD for a year or two and assumed that it would be less suitable for my purposes, ordinary silver printing on VC and occasionally on graded papers, using 120 and some 35mm. I use PMK generally and have been happy with it, except that I've experienced some variations when I've mixed up a new batch (despite being quite careful).

It was Sandy's recent article that prompted me to try his developer. Obviously one needs to be prepared to experiment when starting out on a new and rather different developer. What surprised me, and I still don't understand it, is that I chose the time for gamma=0.5 which I thought would have given me the level of contrast I was looking for.

Anyway, I'll follow your advice and report back.

Thanks again.

 

[sanking]

What surprised me, and I still don't understand it, is that I chose the time for gamma=0.5 which I thought would have given me the level of contrast I was looking for.

John,

Two quick notes.

First, I looked at my data again for the 2:2:100 dilution of Pyrocat-HD with HP5+ and it agrees with the chart in the artilce. For a CI of 0.50 my tests indicate that you need to develop HP5+ for about 6:30 minutes at 72F. This is based on a densitometer reading with the Blue channel and applies to silver gelatin printing.

Second, please note that at another spot in the article I indicated that persons experienced with PMK could correlate that information to the 1:1:100 dilution of Pyrocat-HD by multiplying the PMK time by 0.70. From that I calculate that for normal SBR scenes a time of about 9:00 minutes at 72 F would be about right for HP5+ when developed in Pyrocat -HD 1:1:100.

Hope this information is useful to you.

Sandy

 

[john_s]

Thanks Sandy. It is helpful. It won't take long to home in on the right time. My choice of .5 was just guesswork, since i don't do such measurements. My PMK times are shorter than normal for some unknown reason (not the water quality). I'm hoping that Pyrocat-HD will be more consistent for me from batch to batch. I currently have three lots of PMK all different, all carefully made at different times using chemicals from the same supplier.