Pryocat versus PMK Pyro

[ken_lee11]

Has anyone compared these two different versions of Pyro developer ?

 

According to Sandy King's article, the formulas are different:

Pyrocatechin versus Pryogallol. I am wondering if others have found

the same differences that Mr. King has suggested. Illustrative photos

would be very helpful, but any insights would be greatly appreciated.

[ken_lee11]

I forgot to mention that I scan my negatives and print digitally.

[tim_curry]

The question to be asked is has anyone else done this much study of the two developers. Mr. King's research on this subject will stand for many years to come as an in depth study of staining developers. You would have to invest an incredible amount of time and money to do half of what he has, and has shared so willingly.

 

I think if you are able to read, digest and understand what is being stated, you don't need the pictures.

[guy_mansford]

Ken, I think this is a very sensible question, and one I've been looking at for the past few weeks. I have been developing parts of the same film in PMK and PyroHD. The stain colour is different but both scan very well. They both give a very similar film speed and have that wonderful staining developer "look" to them, but there are differences.

 

I found PyroHD to be slightly finer grained and to have slightly better detail. Not a lot but noticeable. It also (in the phenidone version) gives one third to one half stop extra speed.

 

I have only used delta 100, fp4+ and acros so far. Yet to do is Tech pan (for which 1/3+2+100 PMK is brilliant) and a host of other! In passing, acros is a film I haven't liked before, yet it is incredibly sharp and fine grained in Pyro HD. I might even try tmax100 again.

[arne_strasser]

Pyrocat lacks the interesting green tone - no, seriously, Pyrocat does have several advantages:

 

- half the price when made from scratch

 

- prints (at least) just as well

 

- more speed (1/3 - 1 f-stop)

 

- slightly thighter grain

 

 

One thing, that I cannot confirm, however, is the "ease" of development. My PMK-negs turned out fine from the start, apart from film-speed issues. With pyrocat I had streaks on my first rolls until I added some EDTA to solution A. This problem has disappeared since then.

 

In general I would prefer Pyrocat, unless I have negs with very high contrast shot at a very low film-speed (1/4 of rated speed).

[patrick_gainer]

Hydroquinone is even cheaper than catechol (pyrocatechin). It is also a staining developer. Catechol and hydroquinone are both dihydroxybenzene. Hydroquinone is 1,4 dihydroxybenzene, catechol is 1,2 dihydroxybenzene. This alone would not guarantee that they act alike in developers, but I have tried both and there is not much difference.

[john_stockdale2]

Patrick, hydroquinone is very cheap. If you made up Pyrocat-HD using hydroquinone instead of pyrocatechin, what would you get?

[patrick_gainer]

A proportionally stained negative of quite fine grain is what you would get. It's cheap enough to try.

[ed b.]

I ran some price tests on mixing your own a few years ago (and prices haven't changed much since then). Buying bulk chemicals in reasonable quantities, Pyrocat-HD costs about 15 cents per liter of working solution. PMK comes in at 31 cents. PMK premixed from Photographer's Formulary was 50 cents per liter, and Rodinal at 1:100 was 21 cents.

 

The only advantage of Pyrocat-HD that hasn't been mentioned above is that it can handle low levels of agitation better than PMK, so it is feasible to do stand or (better) semi-stand development.

[sandy_king]

John Stockdale , on nov 06, 2003; 09:13 p.m. asked,

"Patrick, hydroquinone is very cheap. If you made up Pyrocat-HD

using hydroquinone instead of pyrocatechin, what would you

get?"

 

 

And Patrick Gainer , on nov 08, 2003; 01:11 p.m. answered.

"A proportionally stained negative of quite fine grain is what you

would get. It's cheap enough to try."

 

The fact that pyrocatechin tans and hardens the gelatin is at

least as important as the fact that it stains because it is the

tanning and hardening that is responsible for the enhanced

sharpness that one sees in developers like PMK and

Pyrocat-HD . Hydroquinone might stain and tan just as well as

pyrocatechin in the Pyrocat-HD formula but I would not assume

that to be the case without actually verifying it in testing.

 

Since I know that Patrick Gainer is very interrested in Vitamin C

developers I should mention that I experimented once with the

Pyrocat-HD formula by adding a very small amount of Vitamin C.

The result was really dramatic as the Vitamin C was strongly

super additive with one of the other reducers in the formula, or

with both of them, and the developer became much more

energetic, with development times shortened by half or even

more. But the stain completely disappeared. I lost my notes

from the experiment and don't remember exactly how much

Vitamin C was added but it was equal to or less than the amount

of phenidone.

[patrick_gainer]

Sandy,

 

Nice to meet you.

 

I found out about the staining-tanning characteristics from a Kodak technical paper wherin pyrogallol, catechol and hydroquinone were all in the samw category, so I tried it out. What I did first was the obvious. Since catechol and hydroquinone have the same molecular weight, I just substituted for the catechol in Pyrocat-HD. It worked quite well. It does tan as well as stain.

 

Next I dissolved the phenidone and hydroquinone in alcohol, leaving out the bromide and bisulfite. Thus I was able to try a completely sulfite-free version. The phenidone-hydroquinone superadditivity is not present without some sulfite, but the simple additivity does the trick and I think not having any sulfite increases the stain. I am also now working on an article for PT describing the use of organic solvents for various stock solutions which will preserve the developing agents for long periods without the use of sulfite. Sulfite -free developers are generally surface developers, which have as a rule better speed-grain-acutance properties than more ordinary types.

 

I'm sure the economy is not all that great, but it is nice to know that if you want to try the Pyrocat-HD type of developer and happen to have some hydroquinone on hand, you won't have to buy a bunch of catechol.

 

If you want to try the alcohol bit, go to the auto supply store and get some gas drying stuff. You can usually find both Isopropyl and methy alcohols, and both are quite water free and cheap. The Iso is safer.

 

You could also use antifreeze. The green stuff won't hurt anything. You will have to heat it quite a bit to dissolve the catechol or hydroquinone and phenidone, but they will stay dissolved. I use a microwave and bring the soup up to 250 degrees. I know, you think I'm crazy. I know I am, but it works. No sulfite, more stain and more tanning, fine grain, beautiful gradations.

[charles_hoskinson]

I made tests of IFORD Delta 100 in Pyrocat-HD and an alternative staining developer based on Patrick Gainer�s suggested 1:1 substitution of hydroquinone for the catechol in Pyrocat-HD.

 

All stock solutions were prepared in the lab under a hood using a combination hot plate and magnetic mixer/mixer bar. The maximum mixing temperature I used was 52 deg C.

 

I mixed the Pyrocat-HD from a Photographer�s Formulary Kit using the lab supply of deionized water.

 

The alternative �roll your own� developer:

 

Stock Solution A

 

*0.2 grams Phenidone

 

*5.0 grams Hydroquinone

 

I dissolved the phenidone and hydroquinone in 30 ml of Methanol at ~ 21 deg C.

 

I then added Ethylene Glycol to 100 ml.

 

Stock Solution B

 

*100 grams Potassium Carbonate (anhydrous)

 

Deionized water to 100 ml

 

*I cheated and weighed all the dry chemicals for the �roll your own� developer on a lab balance under a hood (I�ve also been known to use spoons).

 

1 shot working solution:

1 part A, plus 1 part B, plus 100 parts deionized water**.

 

**When mixed, the working solution turned yellow, then amber, and then began to turn �Dektol Brown.� I assumed this was probably due to oxygen trapped in my deionized water, and processed my film in it anyway. The resulting negatives were clean, uniform, high acutance, proportionally stained images similar to but not identical to my control images developed in Pyrocat-HD.

 

I rated Ilford Delta 100 120 roll film (6x12 format, 4 rolls) and 4x5 sheet film (8 sheets) at EI 50. I then photographed the same pictorial (nature) subjects on both film formats with my Wista SP 4x5 Field Camera and 55mm Rodenstock Apo Grandagon. Half the film was processed in Pyrocat-HD (1:1:100) and half in Gainer�s suggested alternative. The processing time was 8 minutes, 45 seconds at 23 deg C for both developers, with 1 gentle 5 second agitation cycle per minute for both the roll film (small tank, Hewes reels) and sheet film (Summitek 4x5 cradle in an 11x14 tray). Development was followed by a water rinse � no stop bath. Fixing was with Photographers Formulary TF4 Archival Fix.

 

My next step is to scan these negatives and see how well they print.