Pyrocat-HD formula and variations

<br>

<b>This summary from MichaelandPaula.com is to memorialize on

Photo.Net, for easy searching, a part of <a href

= "http://www.michaelandpaula.com/mp/AzoForum/one.asp?

ID=1914&PgNo=2&GID=1914&CID=2" target = "_blank"><u>this

thread</u></a> on the Pyrocat-HD staining developer formula. I

recommend examining the whole thread, as well as other threads in the

<i>Chemistry</i> and <i>Film Developing</i> forums.<i>Note: All links

open in new windows.</i></b>

<br><br>

REPLY: Pyrocat HD <br>

Posted by: Sandy King Posted at: 12:25:55 PM PT, 7/7/2003 <br><br>

 

Michael, <br><br>

 

Pyrocat-HD is a pyrocatechin/phienidone based developer formula that

I developed about ficw years ago for rotary processing of sheet film

in tubes and drums. In this application it has some clear advantages

over pyrogallol based developers like ABC Pyro, PMK, Rollo Pyro and

WD2D because it is less likely to cause stains and uneven

development. However, a lot of photographers have found that Pyrocat-

HD works well with tray processing as well, and I know of quite a few

who are using it with development by inspection, which is the primary

reason I joined in this discussion on the AZO forum.

<br><br>

I am happy to post the formula here, and folks shold know that other

than the formula at www.unblinkingeye.com this is the only one I

authorize and/or have checked for accuracy. I say this because I have

seen errors in the formula at other sites. I would add that Pyrocat

is sold as a kit by Photographer's Formulary but I have no control

over its production and can not vouch to the accuracy of the formula.

<br><br>

Basically, Pyrocat-HD is mixed as two stock solutions that are

diluted to make a working solution for developing. I recommend the

1:1:100 solution for silver printing, 2:2:100 for alternative

printing, and for soft grades of AZO.<br><br>

<b>

PYROCAT-HD FORMULA </b> <br><br>

 

<b>Stock Solution A </b>

<li>Distilled Water 75ml

<li>Sodium Bisulfite 1.0g

<li>Pyrocatechin (Catechol) 5.0g

<li>Phenidone 0.2g

<li>Potassium Bromide 0.2g

<li>Water to 100ml </li>

<br><br>

<b>Stock Solution B </b>

<li>Distilled Water 100ml

<li>Potassium Carbonate 100g </li>

<br><br>

<b>Mixing Hints: </b><br>

 

<li>The stock solutions have good keeping qualities, on the order of

4-6 months or even longer, so mix in 500ml of 1000ml quantity if you

will be doing a lot of printing, and/or find it difficult to measure

to accuracy of 0.1g

 

<li>It is hard to dissolve Phenidone in water. Consider first mixing

it with a few drops of alcohol, then adding to water

 

<li>Add the Potassium Carbonate slowly to the water as a strong

exothermic reaction is caused. The total amount of Stock B will be

approximately 130ml </li>

<br>

 

For silver printing dilute as follows: <br>

 

1:1:100, or 1 Part Stock A plus 1 Part Stock B plus 100ml of water

<br>

 

For alternative printing, and AZO use the more energetic 2:2:100

dilution <br><br>

 

Some suggested develoment times are posted at <a href

= "http://www.unblinkingeye.com" target

= "_blank><u>www.unblinkingeye.com</u></a>, and some other test

results can be found on the B&W forum at <a href

= "http://www.apug.org" target = "_blank"><u>www.apug.org</u></a>.

For films not covered consider the following:

 

<li>For silver printing use the 1:1:100 dilution and a time of about

20% less than PMK with same film.

 

<li>Times for Pyrocat-HD at the 2:2:100 dilutin are virtually

identical to those of Rollo Pyro with the same film and develoment

conditions.

 

<li>Develop about 20% more with Pyrocat-HD, 2:2:100 dilution, than

with ABC Pyro for rougly comparable CI.

<br><br>

A friend and I are considering doing a small book on Pyrocat-HD so

any comments or feedback based on actual use would be appreciated.

<br><br>

Sandy King

<br><br>

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<br><br>

<b> REPLY: Pyrocat HD </b><br>

Posted by: Don Miller Posted at: 3:00:30 PM PT, 8/22/2003 <br><br>

 

For those who may have Sodium Carbonate on hand and are contemplating

switching to Pyrocat HD. I use Sodium Carbonate in place of Potassium

Carbonate. After discussing this with Sandy King, he indicated that

the two compounds could be exchanged with the condition that 100 gm.

Sodium Carbonate be mixed with 500 cc of water rather then the 100

gm. of Potassium Carbonate in 100 cc of water. The reason is that

Sodium Carbonate reaches saturation [reaches the precipitation point -

- <i>DLS</i>] more rapidly then Potassium Carbonate. It just saves

having another chemical to stock. <br><br>

 

My new mixture is 1-5-100 for negatives that I intend on enlarging

and 2-10-100 for negatives printed on Azo. I have found that FP4 and

Classic 200 have no problems in reaching suitable densities with

Pyrocat HD. I developed an N development FP 4 neg I shot yesterday

for 9 1/2 minutes at 70 degrees and the density range was 1.32 (high

density minus low density measured on blue channel of densitometer.

<br><br>

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<br><br>

<b> REPLY: Pyrocat HD </b><br>

Posted by: Sandy King Posted at: 4:50:57 PM PT, 8/22/2003 <br><br>

 

A brief comment to two issues from a previous post.<br><br>

 

"This is one of the few developers that does not use sodium sulfite!

It does not oxidize like ABC does, and appears to not need sulfite to

prevent rapid deterioration."<br><br>

 

One of the advantages of pyrocatechin is that it does not oxidize as

rapidly in alkaline solutions as pyrogallol. However, with very

active agitation, as in Jobo at maximum speed, Pyrocat-HD does indeed

oxidize, though not as much or as fast as Pyrogallol based

developers. With Jobo and other types of rotary processing I

recommend very slow rotation to minimize oxidation. <br><br>

 

Also, it should be pointed out that Pyrocat-HD does need some sulfite

to prevent excess b+f or general fog. This is provided by the small

amount of sodium bisuilfite in the A solution, which serves two

roles. Sodium bisulfite serves as a preservative for the stock

solution, but when it is mixes with the potassium carbonate alkali it

forms sulfite through reaction, and this small amount of sulfite is

enough to prevent excessive general stain. <br><br>

 

?Potassium Carbonate has a strong restraining action. I tried it in

the PYRO ABC formula awhile back, in place of the Sodium carbonate,

and the negatives were much weaker and thinner--unprintable. The

Pyrocat formula apparently needs this restraining action because the

Phenidone is a very energetic developer.?

<br><br>

 

You may need to re-visit this concept. Based on my own experience,

and considerable reading in the literature, potassium and sodium

carbonate provide virtually identical results in almost all developer

formulas when used at equivalent weight. This is definitely true in

the Pyrocat-HD formula. All of my early experimentation with Pyrocat

was based on sodium carbonate and I only began to use potassium

carbonate because of its greater solubility. <br><br>

 

Sandy King

<br><br>

------------- <br><br>

 

<b> REPLY: Pyrocat HD </b> <br>

Posted by: Paul A. Yesnosky Posted at: 7:56:54 PM PT, 8/22/2003

<br><br>

 

My experience is that sodium carbonate works fine as long as you have

equivalent weight as Sandy said.

<br><br>

I have been using a 10% sodium carbonate solution instead of the 100%

potassium carbonate solution for part B and 10x the ratio with

excellent results in Jobo Expert drums.

<br><br>

So with the 10% sodium carbonate part B, I typically mix 1:20:100

(instead of 1:2:100) and process for 10 minutes at 75 deg F for N+1

development. A lot of my subjects tend to be a little flat and I've

been getting good results and my Azo prints look great (though I

still consider myself a beginner). I think I read one of Sandy's

posts that talked about getting about 1 stop expansion if you go

1:2:100. I've been shooting either Bergger 200 or JandC Classic at

ISO 100.

<br><br>

A lot of the posts in this thread recommend 2:2:100 (or for me would

be 2:20:100). I'm assuming this would just give me more density than

I'm already getting??

<br><br>

From my limited experience, the storage life of the stock solution of this great developer is not long - I would say 4 or 5 months - max.

 

I mixed up some Photographer's Formulary Procat HD stock just a few months ago. It worked great initially both in Jobo and hand inversion at 1:1:100, but now it's alreay dead.

 

I ruined two rolls in it last week - my film came out completely clear - a first. On the other hand, my WD2D+ at 1:1:50, opened one year ago, is still running strong.

Pat Gainer has formulated an alternative to Pyrocat-HD, that is made up in a solution of triethanolamine, that will last forever on the shelf, and has a cool name.

 

 

 

In the March/April 2004 edition of Photo Techniques, Pat Gainer published his

CAT-P-TEA formulation:

 

Triethanolamine------100 ml

Phenidone------------0.2 grams

Pyrocatechol---------10 grams

 

Heat the triethanolamine to dissolve the phenidone and pyrocatechol.

 

For use, dilute 1 part CAT-P-TEA with 50 parts of water

__________________

Jay, Can you give some developing times/temps. for various films and agitation protocols for P-CAT-TEA. And how do you think it compares to

P-C-TEA which I know you like alot?

Michael,

 

If you live in N. America you can simply go to the phototechmag.com site and order a reprint of the article that Jay cites (it's in the March/April 2004 issue with a title akin to "The role of Anti-Freeze in the Photgraphic Proces" or similar) for $5 USD. I've done that and am eagerly awaiting its arrival.

 

The good news is that most of the constituents are relatively inexpensive and easily obtainable.

Michael, I use a similar developer that uses Hydroquinone in place of Pyrocatechin (QP-TEA ) , and I've never tried the Cat-P-TEA. I use QP-TEA diluted 1:25, or 1:50, depending on the film and lighting. AT the 1:50 dikution, I develop 100 speed films like FP4+ for 7 min. @ 70F, and 400 speed films like Tri-X, for 10Min.@70F, just like PC-TEA. With the help of people like Pat Gainer, who developed this approach to formulation, and Sandy King, who developed the Pyrocat formula, these developers continue to evolve. There's an interesting discussion at Mike Smith's Azo forum, on this very topic.

 

http://michaelandpaula.com/mp/AzoForum/one.asp?ID=5999&PgNo=&GID=5999&CID=2

 

 

I'm having a ball exploring the potential of these developers, and I expect to make some important improvements to my favorites, very soon. I'm glad to see other photographers take an interest in Mr. Gainer's unique approach to formulating developers, and look forward to benefitting from your experiences with them. If I can help in any way, I'm happy to do so. Good luck, and enjoy.

I have stored mixed solutions A and B in partially full bottles for up to a year with no degradation.

Two observations.

 

First, Pyrocat-HD stock solutions, if not contaminated, have a shelf life in excess of

one year. Reports of death of the stock solutions in 3-4 months are not consistent

with the literature on this developer and suggest contamination of one or both stock

solutions.

 

Second, the Cat-P-Tea formula mentioned in an earlier post, though an interesting

developer in its own right, gives very different results (less energetic, longer

development times) than the Pyrocat-HD formula. The reason is that the pH of a

working solution of Cat-P-Tea, at about 9.7, is much lower than a working solution

of Pyrocat-HD, at 10.9. Since the threshold of development of pyrocatechin is about

9.5 the Cat-P-TEA formula does not produce a lot of energy and development times

are quite long when compared to Pyrocat-HD.

 

Sandy