How to use Pyrocat M?

pkr1979 · Dec 29, 2020

Hi all,

Im about to mix up some Pyrocat M for the first time (I have never used Pyro before), and I’m curious to know other folks experiences. I’ve read M has a slight loss in film speed compared to HD... but what is slight?

Furthermore, Im intending to develop in Jobo drums (rotary on Jobo machine) and in Patterson tanks (hand). I’m using TMax 400 so exposure and dev times for that film is of particular interest.

Also, as far as I know there is a few variations of Pyrocat M, and I guess the specific variation might be of importance when it comes to dilutions and times.

Cheers
Peter

Ian Grant · Dec 29, 2020

I use Pyrocat HD, it will be more active because of the Ratio of Phenidone to Pyrocatchin, with Super additivity Phenidone is 2 to 10 times more active than Metol, but less active on its own.

There 2g Phenidone to 50g Pyrocatchin in Pyrocat HD but only 2.5g Metol to 50g Pyrocatchin in Pyrocat M, to be equvalent it would need 20g Metol. As a consequence Pyrocat M will be slower working but also give more edge effects as it's close to Hans windisch's Pyrocatechin Surface developer.

Having said that it'll be an equally good developer with slight differences, I can't recommend a time but Tmax 100 & 400 when I used them were excellent in Pyrocat HD but I always shot them at half box speed. I'd do some tests with a roll of 35mm Tmax. I's shoot a few frames at different EI's then in the darkroom cut those frames of film and process, then adjust based on the results shoot some more and adjustr to get the tesults you want.

Ian

john_s · Dec 29, 2020

If I remember correctly there was an earlier version of Pyrocat with 25g of metol ("with a slight loss in film speed") instead of phenidone, i.e. the usual recommended substitute amount of metol being about x10 the amount of phenidone, as in Sandy King's article which was the first I read about Pyrocat-HD:

https://unblinkingeye.com/Articles/Pyrocat/pyrocat.html

I think I read here that someone wrote to Sandy King to say that much less metol was as good as the much larger amount, as strange as it seems, which is the current Pyrocat-M formula.

pkr1979 · Dec 30, 2020

Thanks - both of you,

I’ll use 2.5 g instead of 25. Ian, in Pyrocat HD... what kind of processing methods, times and temps did you use for TMax 100 and TMax 400 when you exposed at half box speed? At unblinking eye Sandy gives 12 min at 21C for TMax 400 at 320 in a Jobo machine... Im likely to use my Jobo as well, particularly for 8x10. However, Patterson tanks are convenient for roll film. However, I have no idea how he timed it. When I time using a Jobo I time from first contact til next first contact (as instructed by Tetenal).

Cheers
Peter

Ian Grant · Dec 30, 2020

Chris, it;s some years since I used Tmax 100 & 400 but always at half box speed, both have been upgraded slightly since but i doubt that makes any difference to EI and Dev times.

I use Jobo tanks for 5x4 but they are the older 2000 series pre Rotary so inversion agitation, Usually I process all films except Fomapan 100 & 200 for 15 to 17 mins at 20ºC and that included Tmax 100 & 400 before I switched to Delta 100 & 400. Same times in a Paterson tank for 120 filmand the odd roll of 35mm. Inversion agitation ever 30 secs first 2 mins then every minute.

Ian

Andrew O'Neill · Dec 30, 2020

I use Pyrocat-HD. For TMY, EI 250. 9:00, 21°C, rotary.

john_s · Dec 30, 2020

Before Pyrocat, Sandy King had a developer called PMC (Pyrocatechol, Metol, Carbonate) which (look below at the cut-and-paste article I copied a long time ago) is actually the modern Pyrocat-M, except for the Part_B.

I used it for many rolls of Neopan400. I regularly use half box speed for all films (except for Microphen in available light situations like theatre) and the combination was actually a bit lower than half box speed. It all depends on one's metering procedure, and I must add that I was using a Mamiya 6 (not the old folder) which hasn't a particularly good meter in that it is overly influenced by bright sky, for which I compensated by pointing the camera down while metering. Anyway, if the OP is looking for a starting EI, a suppose half box speed is as good a place to start as any.

<start of comment by Sandy King from a long time ago, copied maybe from rec.photo.darkroom, or maybe here at APUG>:

"Yes, the PMC formula, which seems very stable in working solution, keeps
well in A and B concentrated solutions. And yes, the same procedures and
conditions (low sulfite and alkaline processing) that are used to intensify
staining with PMK also apply to Pyrocatechin. But no, I don't intend to
write "the book of catechol." Too many other writing projects on hand for
that.

The stock solutions are prepared as follows.

Stock A
Distilled Water 75ml
Sodium bisulfite 1g
Pyrocatechin 5g
Metol .25g
Water to 100ml

Stock B
Distilled Water 750ml
Sodium Carbonate 100g
Water to 1000ml

Dilute 1 part A + 10 parts B + 100 parts water to make a working solution.
For most films development times should be about 15-20% less than with PMK
to reach the same CI. The working solution has a pH of about 10.4, in
contrast to about 9.6 for PMK.

Sandy King"

Bronson Dugnutt · Dec 30, 2020

135 Kodak Tri-X 400 @ 320
Pyrocat-MC 1+1+100 16:00
YMMV

135 Kodak Tri-X 400 @ 320
Pyrocat-HD 1+1+100 15:00
YMMV

destroya · Dec 31, 2020

I have used pyro-M for years. for TMY, I shoot at 200, develop 1+1+100 at 72 degrees for 15 min. 1 min initial agitation, then 10 seconds every 3 min after. love the results.

I have found that almost all my films work in pyro-m shot at half box speed dev at 72 for 15min with 3 min agitation cycles. a few need 14 min, but for me with a new film, I find 15 min is a perfect starting point.

john

pkr1979 · Jan 1, 2021

Happy new year guys. I'll try this rotary 1+1+100 for 15 min (maybe a little less) at 20C and see where that takes me... I've exposed at 200, 300 and 400.

iakustov · Jan 13, 2021

I use Pyrocat-M formula with Metol (don't remember the amount as I last prepared bottle A more than a year ago and it still looks good. Metol is easier to obtain over here than phenidone). Also sodium carbonate 20% solution for B - so the target proportion should be 1+5+94.
For FP4 at EI 100 I develop for 12 mins at 20C with first 30 secs continuous agitation, then for 10 seconds every minute in both Paterson tank and SP-810 tray.

Anon Ymous · Jan 13, 2021

@iakustov Something doesn't add up with your numbers. Normally, Pyrocat HD part B is 750g potassium carbonate in a total volume of 1l. You can use sodium carbonate instead, but an equimolar amount should be used, in order to get the same alkalinity. Potassium carbonate has a molecular weight of 138,2, while sodium carbonate has 106. This means that instead of 750g of potassium carbonate, 575g of the sodium salt should be used, assuming the anhydrous form. You seem to be using much more alkali in your working solution than normal. Of course, this can be a deliberate choice and give you exactly what you wish, but is certainly not the 1+1+100 dilution that I suspect you aimed for.

iakustov · Jan 13, 2021

Anon Ymous said:
@iakustov Something doesn't add up with your numbers. Normally, Pyrocat HD part B is 750g potassium carbonate in a total volume of 1l. You can use sodium carbonate instead, but an equimolar amount should be used, in order to get the same alkalinity. Potassium carbonate has a molecular weight of 138,2, while sodium carbonate has 106. This means that instead of 750g of potassium carbonate, 575g of the sodium salt should be used, assuming the anhydrous form. You seem to be using much more alkali in your working solution than normal. Of course, this can be a deliberate choice and give you exactly what you wish, but is certainly not the 1+1+100 dilution that I suspect you aimed for.

I use this formula:
A:
water 50C 750 ml
metol 2.5g
sodium metabisulfite 10g
pyrocatechin 50g
water to make 1000ml

B:
20% sodium carbonate

1+5+94 for both silver printing and kallitype.

I think I used this link, however, I am missing potassium bromide in the formula somehow, so not sure.

Sodium carbonate can be substituted for potassium carbonate in the Pyrocat-HD formula. The two carbonates give virtually identical results when used at equivalent chemical weight in the working solution. However, sodium carbonate is much less soluble than potassium carbonate so it must be mixed as a weaker stock solution. To prepare a Stock Solution B with sodium carbonate, add 200g of sodium carbonate to 1000ml of water. To make a working solution for silver printing that would be exactly equivalent to the regular 1:1:100 dilution when using potassium carbonate, mix One Part A + Five Parts B + 94 parts Water. For alternative printing the working solution should be mixed 2:10:92 to exactly match the 2:2:100 dilution with potassium carbonate. For all practical purposes you could just mix the working solutions with sodium carbonate at 1:5:100 or 2:10:100 and make minor adjustments to development times as required.

Anon Ymous · Jan 13, 2021

@iakustov I really don't understand how they got to these figures. If you were using the regular potassium carbonate solution, then you'd use 0,75g of potassium carbonate per 100ml of developer working solution. You are now using 1g of sodium carbonate instead of 0,575g. There's also no hydrate of sodium carbonate that would make the 1+5+100 dilution correct. As it is, 1+3+100 would be fairly close.

iakustov · Jan 13, 2021

Anon Ymous said:
@iakustov I really don't understand how they got to these figures. If you were using the regular potassium carbonate solution, then you'd use 0,75g of potassium carbonate per 100ml of developer working solution. You are now using 1g of sodium carbonate instead of 0,575g. There's also no hydrate of sodium carbonate that would make the 1+5+100 dilution correct. As it is, 1+3+100 would be fairly close.

Either this is a typo or there is no practical difference between 1% and 0.5% of sodium carbonate in the target solution, I don't know..

pkr1979 · Jan 26, 2021

Hi again,

So, I finally got around to mix up Pyrocat-M. A question for dilution and time/temp though (film is TMax 400 if relevant)... Im reading a 1+1+100 dilution is good for silver prints while a 2+2+100 is good for alt. processes. But Im also reading that Pyrocat is the better developer for making dual-purpose negatives... The way I understand this is that you can use the same neg for both silver printing and say carbon printing (https://unblinkingeye.com/Articles/PCat/PCat3/pcat3.html). Or am I missing something? To make these negatives is it referring to the 1+1+100 dilution or the 2+2+100 dilution? Or some other dilution?

Also, any ideas about film capacity? Is, say, 500ml of working solution sufficient for rolls of 120?

Cheers
Peter

Sirius Glass · Jan 26, 2021

pkr1979 said:
Hi again,

So, I finally got around to mix up Pyrocat-M. A question for dilution and time/temp though (film is TMax 400 if relevant)... Im reading a 1+1+100 dilution is good for silver prints while a 2+2+100 is good for alt. processes. But Im also reading that Pyrocat is the better developer for making dual-purpose negatives... The way I understand this is that you can use the same neg for both silver printing and say carbon printing (https://unblinkingeye.com/Articles/PCat/PCat3/pcat3.html). Or am I missing something? To make these negatives is it referring to the 1+1+100 dilution or the 2+2+100 dilution? Or some other dilution?

Also, any ideas about film capacity? Is, say, 500ml of working solution sufficient for rolls of 120?

Cheers
Peter

Enough to cover the film. Less for Jobo processors, as marked on the tanks. I use slightly more than the minimum for one roll of 120 or 135.

john_s · Jan 27, 2021

pkr1979 said:
.........

Also, any ideas about film capacity? Is, say, 500ml of working solution sufficient for rolls of 120?

Cheers
Peter

I use 500mL per roll (35mm or 120). I'm sure I could get away with less, but Pyrocat is extremely cheap to make and I view my minor "extravagance" as cheap insurance. I just use 1+1+100 for conventional silver prints. Maybe a search for Sandy King here at APUG would find some comments about dilutions and contrasts for alternative processes and dual purpose negatives.

pkr1979 · Jan 27, 2021

Thanks. I did look around but its still slightly unclear too me... It appears to me that if one develop with 1+1+100 the neg can be used for silverprint an pt/pd... or UV light copying - like carbon prints. Also, as far as I can understand from the different posts negs intended for VC paper needs 25 % longer development time then times given (without being sure what times it is referred to)? I might have misunderstood something though.

Also, when developing with Pyrocat... does the process deviate in any other way? When developing BW negs in Jobo I would pre-wet, develop, plain water stop bath, fix, and then stab. Is this the same for Pyro?

Anon Ymous · Jan 27, 2021

Please tell me that you wash between fix and "stab".

john_s · Jan 27, 2021

pkr1979 said:
Thanks. I did look around but its still slightly unclear too me... It appears to me that if one develop with 1+1+100 the neg can be used for silverprint an pt/pd... or UV light copying - like carbon prints. Also, as far as I can understand from the different posts negs intended for VC paper needs 25 % longer development time then times given (without being sure what times it is referred to)? I might have misunderstood something though.

Also, when developing with Pyrocat... does the process deviate in any other way? When developing BW negs in Jobo I would pre-wet, develop, plain water stop bath, fix, and then stab. Is this the same for Pyro?

The issue with VC paper and stained negatives was more of a problem with PMK where the image stain could be somewhat greenish rather than brown (mine were not noticeably green but I've seen images in which the PMK negs were quite green). Green acted as to modify the light source wwhen exposing VC paper and so reduced contrast. However the stain from Pyrocat is more brown and the effect is a lot less, so I don't think you need to worry about it. To the extent that it still works, it results in a neg that's effectively a bit less contrasty with VC paper than graded paper (and hence some alternative processes if they are sensitive only to blue/violet). The negs can then be called "dual purpose."

pkr1979 · Jan 27, 2021

Anon Ymous said:
Please tell me that you wash between fix and "stab".

I do... Sorry... pre-wet, develop, plain water stop bath, fix, wash, and then stab. Is this the way to go when developing with Pyrocat as well? Sandy seems to suggest in the original article to do one minute hypo-clearing (1 % sodium sulfite solution)... is this something usually done when using Pyrocat, if so why? And I assume this step is between Fix and Stab?

john_s said:
The issue with VC paper and stained negatives was more of a problem with PMK where the image stain could be somewhat greenish rather than brown (mine were not noticeably green but I've seen images in which the PMK negs were quite green). Green acted as to modify the light source when exposing VC paper and so reduced contrast. However the stain from Pyrocat is more brown and the effect is a lot less, so I don't think you need to worry about it. To the extent that it still works, it results in a neg that's effectively a bit less contrasty with VC paper than graded paper (and hence some alternative processes if they are sensitive only to blue/violet). The negs can then be called "dual purpose."

OK - I see... the longer development time is for increased contrast necessary for VC paper. This is probably self explanatory for many of you and I have to admit I havent done alot of negative developing (mainly positives), and hardly any printing at all - so Im not really that familiar with what a paper need from a negative and how to adjust for that

Anon Ymous · Jan 27, 2021

The sodium sulfite bath isn't necessary, but won't harm and will help wash film quicker, that's all. It's not Pyrocat specific at all. You can also use a stop bath if you wish, although half strength might be a good idea.

pkr1979 · Jan 27, 2021

Anon Ymous said:
The sodium sulfite bath isn't necessary, but won't harm and will help wash film quicker, that's all. It's not Pyrocat specific at all. You can also use a stop bath if you wish, although half strength might be a good idea.

Ah. I see. Thanks.

esearing · Jan 30, 2021

pkr1979 said:
Hi again,

So, I finally got around to mix up Pyrocat-M. A question for dilution and time/temp though (film is TMax 400 if relevant)... Im reading a 1+1+100 dilution is good for silver prints while a 2+2+100 is good for alt. processes. But Im also reading that Pyrocat is the better developer for making dual-purpose negatives... The way I understand this is that you can use the same neg for both silver printing and say carbon printing (https://unblinkingeye.com/Articles/PCat/PCat3/pcat3.html). Or am I missing something? To make these negatives is it referring to the 1+1+100 dilution or the 2+2+100 dilution? Or some other dilution?

Also, any ideas about film capacity? Is, say, 500ml of working solution sufficient for rolls of 120?

Cheers
Peter

Good for you. Pyrocat-M is a nice developer and works very much like Pyrocat HD for Ilford FP4 and Delta 100. For 8x10, 1 roll 120, OR 1 roll 135. 1:1:100 works very well. If you want to boost edge effects for a single sheet of 4x5 you can dilute it down to 3.5:3.5:500 extending time 2-3 minutes but reduce agitation to every 3 minutes in a tank (13-15 mins @ 70*). For really long minimal agitation/semi-stand you can get away with 3:2.5:500 for a single sheet at 25-30 minutes depending on scene contrast. Agitations should be 30-40 seconds at least 3 times during the development with a solid 2 minutes initial agitation. With the Metol version vs HD I moved away from long periods and tend to work in the 12-15 minute range now with similar results. The Metol acts as a second developer once the catechol starts to deplete. I have not had any failures that I experienced with HD. I also like my negatives a little on the thin side so you may want to add more time or stronger dilution. Weaker dilutions have less brown stain so may not be what you want for Alt printing.

If it turns blue when you add part B then the metol has expired. I got one year out of my first batch in a 250ml brown bottle.

How to use Pyrocat M?

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