why Pyrocat?

[bobwysiwyg]

I use both 35mm and 4x5. I shoot mostly B/W processing my own using D76. I've been interested in trying other developers and have seen frequent references to Pyrocat. Can anyone explain it's virtues or pros and cons for me. Oh, I've generally been using T-Max film if it matters. Any input would be appreciated.

 

[Rudeofus]

Catechol (aka pyrocat) and Pyrogallol are developers which will not only form image silver, but also form a brown stain wherever silver was developed. This gives some degree of image amplification or less grain for same density. Historically Pyrogallol was prefered, but since it is very toxic people moved to Catechol.

There are many resources dedicated to pyrocat developers which list mixing and developing instructions together with properties of their concoctions.

 

[Jim Noel]

Pyrocat is preferred by many current workers over pyrogagallol (pyrogallic acid) for several reasons.
1. somewhat less toxic although gloves should be worn with both.
2. The stain is less intense, but a part of the spectrum which provides for more contrast in the print.
3. The stain masks the grain of the film.
4. the printing time is usually shorter than for pyrogallol negatives.
5. Both forms of pyro tan the emulsion providing more protection from scratches.
6. Separation in the highlights is superb when compared to MQ or PQ developers
7. It is probably the cheapest developer around when diluted to working dilutions.
8. if mixed in polyethylene glycol, which it should be, it lasts for an extreme length of time. I have never had any go bad.
9. the scale of the negative is enhanced because the film curves don't have unusual fluctations.
10. since the concentrates are liquids, it is quick to get ready for use.

I can go on, but this should be enough. By the way,I have spent considerable time over the past 70 years working with various develoers and currently still maintain solutions of four different pyro develpers. Pyrocat HD+ is my absolute favorite.

Jim

 

[pdeeh]

Do you mean Propylene glycol?

 

[bobwysiwyg]

First ask yourself what sort of direction you want to move in vs stock D-76. Asked another way, what specifically don't you like about it, or what specifically you are looking for. .

Michael, excellent question. I can't say I dislike anything about D76. Probably more curiosity. Good food for thought. Thank you for your candor.

 

[Ian Grant]

Pyrocat is preferred by many current workers over pyrogagallol (pyrogallic acid) for several reasons.
1. somewhat less toxic although gloves should be worn with both.
2. The stain is less intense, but a part of the spectrum which provides for more contrast in the print.
3. The stain masks the grain of the film.
4. the printing time is usually shorter than for pyrogallol negatives.
5. Both forms of pyro tan the emulsion providing more protection from scratches.
6. Separation in the highlights is superb when compared to MQ or PQ developers
7. It is probably the cheapest developer around when diluted to working dilutions.
8. if mixed in polyethylene glycol, which it should be, it lasts for an extreme length of time. I have never had any go bad.
9. the scale of the negative is enhanced because the film curves don't have unusual fluctations.
10. since the concentrates are liquids, it is quick to get ready for use.

I can go on, but this should be enough. By the way,I have spent considerable time over the past 70 years working with various develoers and currently still maintain solutions of four different pyro develpers. Pyrocat HD+ is my absolute favorite.

Jim

Agree 100% with what Jim says, I've tried a lot of developers over the last 50 years and it's the best alround developer I've found, consistenly excellent results and negatives that are remarkably easy to print.

Ian

 

[Ed Bray]

This is the first of my images from negatives that I processed using Divided Pyrocat HD which is supposed to give a compensating effect to high contrast situations, although I normally use Pyrocat HD in its mixed form I thought I would try the divided Pyrocat HD as I wanted to get some detail from the semi-circle window. I am very pleased with the compensating effect, I could not believe the amount of detail from the semi-circular windows bearing in mind how high the contrast between the light outside and the very dark conditions inside.
The measured exposure was 30 secs @ f45 at ISO25, although the exposure I actually gave was 4 minutes at f45 on Adox CHS25 which will give an idea of how dark it was although I did allow 1 stop for reciprocity and I also had the Centre Filter on the 72mm Super Angulon XL which ate up another 2 stops.

Redundant Pressure Filters (Tottiford Water Treatment Works) by Ed Bray, on Flickr

 

[HTF III]

You see all these claims as to how poisonous it is, but at one time it was used as a hair dye (pyrogallol). The same article I read also says metol and hydroquinone are poisonous. I wonder if pyro is really all that dangerous, or is it dangerous by today's standards, where EVERYTHING is poisonous. I'm thinking of switching to it after everything I've read on this site.

 

[markbarendt]

"There is no "free lunch".

This is so true.

 

[bobwysiwyg]

Thanks all for your input. I've decided to give it a try. Just ordered some (SandyK's formula) from Photographer's Formulary.

 

[Klainmeister]

If you're anything like me, you'll find advantages and disadvantages to any developer. I have been using Pyrocat for about 5 years now, mainly because I can actually see an increased acutance in my images vs D76. That being said, I also use Xtol to accomplish a different look. Ultimately, it's best to do some side by side comparisons and see the strengths/weaknesses of each. For how much the chemistry costs, it's a no brainer when it comes to overall expense vs what can gained.

 

[john_s]

You see all these claims as to how poisonous it is, but at one time it was used as a hair dye (pyrogallol). The same article I read also says metol and hydroquinone are poisonous. I wonder if pyro is really all that dangerous, or is it dangerous by today's standards, where EVERYTHING is poisonous. I'm thinking of switching to it after everything I've read on this site.

If you eat smoked meats you are ingesting little doses of pyrogallol. Not good if that's all you eat.

 

[MattKing]

Uh oh. I practically live on smoked meat...

Ah, Montreal ......

 

[HTF III]

Just what I thought. Pyro is no more dangerous than anything else I get all over my hands every day. Thanks. I'm going to get some.

 

[markbarendt]

http://stores.photoformulary.com/images/store_version1/Pyrogallicacid.pdf

http://stores.photoformulary.com/images/store_version1/Catecholmsds.pdf

 

[PhotoJim]

Pyrocat is preferred by many current workers over pyrogagallol (pyrogallic acid) for several reasons.

A lot of these are not advantages over pyrogallol in some formulations:

3. The stain masks the grain of the film.
5. Both forms of pyro tan the emulsion providing more protection from scratches.
6. Separation in the highlights is superb when compared to MQ or PQ developers
7. It is probably the cheapest developer around when diluted to working dilutions.
8. if mixed in polyethylene glycol, which it should be, it lasts for an extreme length of time. I have never had any go bad.
9. the scale of the negative is enhanced because the film curves don't have unusual fluctations.
10. since the concentrates are liquids, it is quick to get ready for use.

5. Tie.
6. Similar. Virtually a tie; it just depends on your preferences.
7. I'd have to crunch the numbers, but most pyrogallol developers like PMK are very inexpensive to use.
8. PMK lasts for years mixed in distilled water. It does not require propylene glycol when mixed.
9. Tie.
10. Tie.

I don't mean to badmouth pyrocatechin developers, merely to point out that PMK has few disadvantages compared to them.

Incidentally, and not related to the original poster, "pyrocat" is the name of a series of formulations using pyrocatechin aka catechol aka catechin (which are all the same developer). I'm not sure, OP, if you were talking about one of these formulas or if you were talking about pyrocatechin.

 

[HTF III]

Far be it for me to call the following source a hallmark of credibility, but I found this to be interesting. If I'm concluding right (which is a stretch), maybe using pyro would actuall be good for me as someone who smokes. Seems the parent acid from which pyrogallol is extracted is a chemical unfriendly to cancer cells. DON'T TAKE MY WORD FOR ANY CLAIMS.
But then when we develop in a developing tank, pouring our chemistry from a beaker, there isn't a whole lot of hand contact any way.
http://en.wikipedia.org/wiki/Gallic_acid

 

[bobwysiwyg]

. I'm not sure, OP, if you were talking about one of these formulas or if you were talking about pyrocatechin.

Sorry but I know enough to answer this.

 

[Tony-S]

Seems the parent acid from which pyrogallol is extracted is a chemical unfriendly to cancer cells. DON'T TAKE MY WORD FOR ANY CLAIMS.

In all likelihood, it is a clinically irrelevant compound for cancers.

 

[Jim Noel]

OOPS - YES PROPYLENE OR POLYPROPYLENE not ehthylene.
Thanks for the heads up.

 

[Andrew O'Neill]

if mixed in polyethylene glycol, which it should be,

Hi Jim, why should it be mixed in polyethylene glycol? If the only reason is indefinite shelf life, that's great for the casual user, but I go through pyrocat stock rather quickly, so for me, there is no point to mixing in polyethylene glycol... unless I'm missing something. Up here in Canada, polyethylene is pretty expensive.