New Pyrocat-M experiences?

[Steve Hamley]

Is the Metol cited in the Pyrocat-MC formula "out of the box" Metol or the converted Metol base as described in Pat's "recipe" post?

Thanks

Steve

 

[gainer]

Is the Metol cited in the Pyrocat-MC formula "out of the box" Metol or the converted Metol base as described in Pat's "recipe" post?

Thanks

Steve

The metol in my version of the formula is out of the box. The TEA and water convert it into the base as you mix it.

 

[Steve Hamley]

Thank you Pat. I thought I'd figured it out from your last post on the recipe thread but thought I'd check. I don't subscribe to the "Ready, Fire, Aim" business model...

Steve

 

[craigclu]

If the cat is out of the bag I guess it's OK to tell it.
You need 2.5 grams metol, 4 grams ascorbic or erythorbic acid, about 8 grams of TEA (about 7 ml at room temperature) and about a teaspoon of water to start.

To save any head scratching that might ensue... 1 teaspoon converts to about 5ml and a tablespoon about 3 times that. In this case, it certainly isn't critical but for the hand wringers among us....perhaps! I use this handy little converter quite often:

Convert

While I'm posting this, I'd like to thank Sandy and Pat for their generous and patient sharing of their experiences and expertise. Your ability to express these photographic and chemical concepts in understandable form have helped me immensely in taming my darkroom issues.

 

[gainer]

Most sets of measuring spoons for the kitchen include 1/2 tablespoon as well as 1/8, 1/4, and 1/2 teaspoons. These are quite handy for measuring small volumes when absolute accuracy is not required. In this case, it is more important to get enough TEA to neutralize both the sulfuric acid part of the metol and the ascorbic acid than to get exact balance. Whether it is 1/2 tablespoon or 5/8 is of little concern. Whether it is 1/2 or less may be, if it means that a little less metol will be dissolved in the glycol.

 

[craigclu]

Pat, I was going to mix up some of the MC and pardon my density, but I got lost at the point of the glycol going in.... Is the entire base (the full liter) propylene glycol? I'll probably mix a partial batch for some comparison testing on medium format but thought I'd get more clear before starting the project.

 

[gainer]

You should wind up with the equivalent of 2.5 grams of metol, 4 grams of ascorbic acid and 50 grams of pyrocatechin (catechol) in a liter of stock which is mostly propylene glycol. A small amount of TEA and water forms a sort of analog of ammonium sulfate, and another small amount goes to form an equivalent of ammonium ascorbate. (I think.) Whatever happens, it's going to take just a few ml of TEA and water and the rest of the solvent will be the glycol.
I think its best to mix the TEA, water, metol and ascorbic acid first and let it work for a while. That's just an opinion based on the idea that if you throw everything in the pot including all the glycol, the initial reaction may not happen for a long time because the requisite molecules would be so widely dispersed. It's the same idea as what happens when you dilute a developer, only worse because the glycol does not promote the reaction the way water does in developer.

 

[john_s]

...... It is really a very nice developer, especially for folks looking for low B+F, very high stain, and very high accutance.
............
Sandy

I now have a backlog of developers to try! But this one looks very interesting. How do you think the grain and speed compare to the original Pyrocat-HD, which I've been using very happily for 120 size Neopan400?

 

[craigclu]

What drew me to this variant of PyroCat is the many concoctions I've dealt with combining Vit C and catechol. I would be getting stunning accutance, smooth grain but too flat a toe and couldn't print around the loss of shadow separations without extreme EI swings and pulled development. Also, my somewhat odd-ball, indexed enlarging meter/timer system behaves so much better as my b+f levels are kept lower (Wallner-Labex). If this can give me the shadow behavior of PyroCat-HD with the added "edgieness" that I've seen with the C/Cat mixtures I've tried or experimented with, along with the stain color of Cat vs pyrogallol advantage for my materials, perhaps this will combine the elements I've been looking for and be just my brew.... If not, I could happily go on using the HD and PG versions, anyway!

 

[sanking]

What drew me to this variant of PyroCat is the many concoctions I've dealt with combining Vit C and catechol. I would be getting stunning accutance, smooth grain but too flat a toe and couldn't print around the loss of shadow separations without extreme EI swings and pulled development. Also, my somewhat odd-ball, indexed enlarging meter/timer system behaves so much better as my b+f levels are kept lower (Wallner-Labex). If this can give me the shadow behavior of PyroCat-HD with the added "edgieness" that I've seen with the C/Cat mixtures I've tried or experimented with, along with the stain color of Cat vs pyrogallol advantage for my materials, perhaps this will combine the elements I've been looking for and be just my brew.... If not, I could happily go on using the HD and PG versions, anyway!

Craig,

Your experience is same as mine. Catechol + ascorbic, even with very low amounts of ascorbic, gives reduced film speed, and the more ascorbic you add the more loss of film speed you get. This is due to the fact that with pyrocatechin and ascorbic you have no synergism so the ascorbic functions merely as a reducer. The result is a developer that acts just like it is pure pyrocatechin (until the reducing factor kicks in), which means you get low film speed with a slow developer action at first that suddenely turns into a trigger-like reaction that results in infectious development. Almost exactly what you would see with a pure hydroquinone developer.

However, the addition of a small amount of ascorbic in place of the sulfite in the Pyrocat-M formula ( Pyrocatechin + metol combination), which gives the Pyrocat-MC formula, is an entirely different beast. You get some additional synergim, the same good film speed as with Pyrocat-HD, low film grain, very low B+F, even with the long develoment times needed for alternative printing, and very high film stain. And equally important, the increase in CI is very consistent and linear with time of development.

Sandy

 

[Tom Hoskinson]

I mixed up a batch of the Gainer/King Pyrocat - MC Formula this afternoon. It was quick and easy to do.

As a fast proof test, I developed a short piece of 35mm Efke KB 25 - Perfect!

Sunday, I expect to use some of it to develop the first 35mm film exposed with my new Zeiss ZM 50/2

 

[craigclu]

I finally got a few minutes to run some MC and got slightly odd results and will rerun when I can to see if I introduced some "operator error" factor. My Macbeth TD-902 showed a FB of 0.41 and my blue channel Wallner-Labex showed a 0.31. I'm accustomed to the opposite reactions on tanned negatives. I also had lower numbers throughout the range on the blue channel. I recalibrated both units and a repeat got the same results. I also found a longer, flatter toe than I had seen with PyroCat-HD. I exposed HP5+ 35mm at 200 and ran 1:1:100 for 13 minutes with 1 minute intervals on 2 gentle inversions. This is very preliminary and I was interrupted during the processing and reminded of a commitment that rushed me through the final stages of rinsing, alkaline fixing and washing so it is quite possible I've sent something amiss... This chart is from my "not ready for public appearances" spreadsheet that I use for quick plots of my tests. The magenta line is the Macbeth @200 numbers, the orange is the Macbeth @100 numbers and the broken blue line is the Wallner-Labex blue channel @200. The dotted line across at 1.32 is simply a baseline for my enlarging equipment that keeps highlights controlled at Zone VIII on #2 materials.

 

[sanking]

I finally got a few minutes to run some MC and got slightly odd results and will rerun when I can to see if I introduced some "operator error" factor. My Macbeth TD-902 showed a FB of 0.41 and my blue channel Wallner-Labex showed a 0.31. I'm accustomed to the opposite reactions on tanned negatives. I also had lower numbers throughout the range on the blue channel. I recalibrated both units and a repeat got the same results. I also found a longer, flatter toe than I had seen with PyroCat-HD.

Craig,

Not sure what is going on with your curves but they is different from what I see. I am attaching a family of curves based on Blue mode analysis of FP4+ film. It is not very different from that of Pyrocat-HD. The stain density is definitely greater in Blue than in Visual, and much greater in UV than in in Blue. For example, Step 1 density at 8, 10, 15 and 20 minutes is as follows.

8 minutes, V(1.28), B(1.50), UV(1.97)
10 minutes V(1.48, B(1.73), UV(2.23)
15 minutes V(1.78), B(2.09, UV(2.72)
20 minutes V(1.92, B(2.24, UV(2.94)

BTW, for those not used to reading BTZS charts, the numbers on each curve represent 1) time, 2) effective film speed, 3) approximate CI, and 4) SBR. The setting are based on an ES of 1.30, which would be appropriate for printing on VC silver papers, and a flare factor of 0.02 was added. The film is fairly old and has a minimum B+F of about 0.12, thus the rather significant increase in general stain with the 15 minute and 20 minute negatives.

Sandy

 

[aligndont]

Regarding pyrocat MC - does the formula contain metabisulfite?

 

[Tom Hoskinson]

Regarding pyrocat MC - does the formula contain metabisulfite?

The Pyrocat - MC formula does not contain metabisulfite. Instead, it contains Ascorbic Acid (which is converted to ascorbate by the Triethanolamine - which also converts the Metol to the Base).

I have compared Pyrocat - HD with Pyrocat - P and Pyrocat - MC. They are very similar developers. I find that I prefer Pyrocat-P for continuous agitation development (and it also works well for stand development).

See my Excel graph of my Pyrocat-P densitometry results in the APUG Technical Gallery.

In my opinion, Pyrocat -MC gives the highest acutance of the 3 versions and slightly higher Effective Film Speed.

 

[gainer]

No metabisulfite or sulfite. I tried this to in order make all active ingredients soluble in glycol, and it works without sulfite. The same ploy works with the phenidone version, but there is no need for TEA to free the phenidone base. In other words, Pyrocat HD with about 1/3 as much ascorbic acid as usually used of metabisulfite, dissolves readily in glycol at a very moderate temperature and works, IMHO, like Pyrocat HD with the metabisulfite. Go figure!

 

[Claire Senft]

I have had my first usage of Pyrocat MC. It went nicely.

 

[sanking]

The Pyrocat - MC formula does not contain metabisulfite. Instead, it contains Ascorbic Acid (which is converted to ascorbate by the Triethanolamine - which also converts the Metol to the Base).

I have compared Pyrocat - HD with Pyrocat - P and Pyrocat - MC. They are very similar developers. I find that I prefer Pyrocat-P for continuous agitation development (and it also works well for stand development).

See my Excel graph of my Pyrocat-P densitometry results in the APUG Technical Gallery.

In my opinion, Pyrocat -MC gives the highest acutance of the 3 versions and slightly higher Effective Film Speed.

In looking at my own tests and some side by side examples that John Berry sent me it appears to me that there may be a slight loss of film speed with Pyrocat-P compared to Pyrocat-HD. It is not great, probably no more than about 1/8 of a stop, but when looking at identically exposed negatives developed to the same approximate CI I see just a little less shadow density in the -P negatives.

I agree with Tom in that the -MC gives slightly higher effective film speed. It also gives slightly lower general stain with very long development times.

BTW, Photograher's Formulary is now supplying both Pyrocat-HD and Pyrocat-MC in kits mixed in propylene glycol.

Sandy

 

[sanking]

BTW, just in case anyone is interested I am attaching the film development data I supplied to the Formulary for the Pyrocat-MC kits. The recommended times are about 10% shorter than with Pyrocat-HD at same dilution and temperature.

Sandy


Pyrocat-MC Film Developer

To make a standard working solution mix 1 part A with 1 part B with 100 parts water.

Use a plain water stop bath for one minute or a acetic stop bath at one-half normal strength. Use an alkaline fixer (rapid fix without hardener or TF-4) for 5 minutes. Wash in running water for 10-15 minutes.

The working solution can be made quite a bit more energetic (faster working) by using a dilution of 3:2:100 or 5:3:100. The stronger dilutions would generally be used only when developing negatives for printing with alternative processes, which require negatives of much greater contrast than silver papers.

One major difference between PMK and Pyrocat-MC is the color of the stain. PMK stain has a strong yellow/green color, which inhibits blue and magenta. When printing on graded paper, the yellow/green stain essentially adds more density to the negative and boosts the contrast. When printing on variable contrast paper, the yellow/green stain tends to reduce contrast, particularly in the high values. These effects can be good or bad, depending on the negative. Pyrocat-MC’s stain is brown in color. Pyrocat negatives print much like PMK negatives on VC papers, though with slightly less highlight shouldering. Pyrocat-MC negatives print faster on graded papers than similar PMK negatives because brown stain doesn’t inhibit the blue light that the paper is sensitive to as much as yellow/green stain.

Suggested Development Times.. The suggested times assume a 1:1:100 dilution of Pyrocat-MC (One Part A + One Part B + 100 Parts Water), with rotary development in Jobo or BTZS tubes. These times, at the temperatures indicates, should give an approximate CI of .55 when measured with a densitometer in blue mode, appropriate for printing on graded silver papers of #2 contrast. For variable contrast silver papers increase development times by about 35%. For developing in tray with shuffle agitation, or in tanks with agitation every 30-60 seconds, increase time of development by about 15%.. When developing with rotary processing, either Jobo or BTZS type tubes, use a minimum of 75 ml of the standard working solution per sheet of 4X5 film, (minimum of 250 ml of working solution for a sheet of 8X10 film). A pre-soak of two minutes is recommended as good practice with rotary processing.

Pyrocat-MC gives negatives of very great acutance with minimal development. When using minimal development extend development time by about 50% over normal time for rotary processing, and agitate every two or three minutes. Minimal development is recommended only when the adjusted development time is fifteen minutes or more.

Film EI 70º 75º 80º
Across 100 7:15 min 5:45 min 4:45 min
BPF 200 100 7:15 min 5:45 min 4:45 min
Delta 100 125 7:15 min 5:45 min 4:45 min
Efke 25 35 6:30 min 4:45 min 3:45 min
Efke 100 100 11:00 min 8:30 min 7:30 min
FP4+ 125 7:30 min 7:15 min 5:30 min
J&C 400 350 9.00 min 7:15 min 5:30 min
Tmax-400 500 9:00 min 7:15 min 5:30 min
Tri-X 320 400 9:00 min 7:15 min 5:30 min

The suggested development times are guidelines. Do not hesitate to increase or decrease time of development over the recommended times if your prints have too little or too much contrast.

 

[sanking]

Over on the LF forum there was some discussion of the Pyrocat-M and Pyrocat-MC formulas. If you read the thread you will see that Jay DeFehr, who was banned from this list for attacking me with a false identity, now claims that I have taken full credit for the Pyrocat-MC formula. DeFehr further claims that the Pyrocat-MC formula preceded the Pyrocat-M formula, which is clearly not true.

Readers of this thread will know that I have fully acknowledged Pat Gainer's collaboration in the development of the Pyrocat-MC formula, for which I am fully appreciative and have freely acknowledged. Pat sent me a note on April 19 about the formula, and I quote: "It is nothing like Hypercat. I will not make this formula public. It is mostly your work. If you want to get someone to produce it, like P. F. or just make it public, go ahead."

And I did both. I got P. F. to produce it, I made it public, and I fully recognized Pat Gainers' role in its development.

Further notes. My original work with the Pyrocat formula was carried out with phenidone. However, once the formula with phenidone was published I kept getting reports from people about substituting metol for phenidone at the same amount. The really confused me, because normally we expect about a 10-15-:1 ration of metol to phenidone to get the same level of activity. But results are results, so in March when I decided to test a couple of Pyrocat variants, the -P and -M variants, I decided to carefully test the optimum amount of metol in the formula, and what I found was that it was indeed about the same amount per weight as phenidone. I don't know how to explain this, but this fact is the primary key to the great qualities of Pyrocat-M and Pyrocat-MC.

Some have pointed out that the original Pyrocat-HD formula with metol did not produce as much EFS as the phenidoen version, and this is true, at least from my tests. However, the current version has completely eliminated the bromide restrainer, and this kicks up the EFS to full emulsion speed.

There is very little difference in results at this point between Pyrocat-M and Pyrocat-MC. However, the former can be mixed in water, while the -MC version must be mixed in glycol. Any of the Pyrocats perform the same mixed in glycol or water. Glycol will most certainly give longer life, however. There are, however, some nuances of difference between Pyrocat-M and Pyrocat-MC, primarily in the amount of actinic fog.

I know that there are many folks using both the Pyrocat-M and Pyrocat-MC formulas. Thank you for your continuing feedback. I will continue to look at resutls and adjust the formula if my tests show that better results are possible.

As for the original Pyrocat-HD formula, it continues to give great results for many people and is now availalble in a glycol based kit from Formulary. And the Pyrocat-P formula appears to be dynamite for edge effects with normal agitation. And this from Clay Harmon from Houston, who probably knows more about this stuff than me.



Sandy

 

[ongarine]

Back from the Dolomites I found some very interesting replies and contributions to my initial question about experiences with Pyrocat M.
After all the reading I have these two doubts to clarify:
A) What could be the shelf life of Pyrocat MC in water instead than glycol?
A day, a week, a month? I know that Vitamin C has a short life in water.
B) I tested Pyrocat HD without metabisulfite and 4 grams of Vitamin C, it was
really interesting even if more contrasty and faster than HD.
Some thoughts to share?
Daniele

 

[sanking]

Back from the Dolomites I found some very interesting replies and contributions to my initial question about experiences with Pyrocat M.
After all the reading I have these two doubts to clarify:
A) What could be the shelf life of Pyrocat MC in water instead than glycol?
A day, a week, a month? I know that Vitamin C has a short life in water.
B) I tested Pyrocat HD without metabisulfite and 4 grams of Vitamin C, it was
really interesting even if more contrasty and faster than HD.
Some thoughts to share?
Daniele

A. Pyrocat-MC mixed in water without a preservative would have a realtively short shelf life. Not sure exactly how long, but I would estimate less than a month. However, you coulld mix Pyrocat-MC in water and add the sodium metabiulfite preservative. That would give you a formula functionally similar to Rollo Pyro, which contains pyrogallol, metol and ascorbic, but with a sodium bisulfite preservative.

B. I agree with your comment that adding ascorbic to Pyrocat-HD gives a faster working formula. I posted some results about this on the AZO forum a couple of years ago.You must be careful, however, because either too much sulfit or ascorbic will reduce or kill the stain.


Sandy

 

[eclarke]

Hi Sandy,
Fascinating stuff. I have been playing the M formula for a week but I have the supplies to mix any of them. In your opinion, which formula for the films you mentioned above would you choose for rotary processing (Jobo)..Thanks..Evan Clarke

 

[lee]

I dont want to cut in here but my impression is that any of the pyrocat versions will be good for rotary processess with all the films.

lee\c

 

[KEK]

Sorry to cut in here also but i've been reading alot of the threads on the pyrocats and i'm a little confused. I just received pyrocat mc in glycol from PF and bought it for a shorter development time and continuos aggitation of sheet film. Did I buy the right pyrocat or are the differences so small between them it doesn't matter.

Kevin