PGK pyro

[mikemarcus]

Pyrogallol is a regenerator of glycin. It seems from my initial tests that sulfite is not needed for this to be true. Whether sulfite makes this process more efficient is a question which I plan to answer in the coming days.

 

[gainer]

Interesting.
I try not to hate people. I sometimes hate the things they do to other people. I would be lost without the scanner, but I would also feel lost without the enlarger. I will say that quite often I am able to get a good print with the scanner from a negative that does not print well at all with the wet stuff. Dense negs OTH seem best attacked in the wet darkroom.

Have you seen any advantage of pyro-stained negatives over the unstained in the scanner?

If in fact pyro regenerates glycin without sulfite, you should be home free. You don't need a preservative when you use TEA as solvent, as long as you keep water out of the stock. If you should find it doesn't work, you can add 1/2 tsp of ascorbic acid powder to the liter of stock. It should have no trouble dissolving except due to the viscosity of TEA, which can be overcome by mild heating in a double boiler. That may not work either, who knows until it's tried?

 

[mikemarcus]

I recently went back to the darkroom to print a work for an open exhibition that I was taking part in. It was my first time in 10 years. I felt like my arms had been chopped off. I feel so comfortable in the digital realm that the physical process of printing, developing, inspecting, (iterate as necessary) seemed to me to be slow and awkward - generally not conducive to creative thought. However (and here is my point) my printing was much better than it was 10 years ago. Why? Because a applied 10 more years of photographic understanding to my work. Basically the principles of wet printing and digital manipulation are exactly the same and to have a good understanding of one is to be proficient in the other. Only the tools need getting used to.

The best way to start either process is with the best negative that you can make and to me, pyro negatives have the look that I'm after. Its not so much about the stain, rather the smooth midtones, luminous highlights and excellent tonal separation. I'm sure that stain contributes to this but i dump the blue channel and work from the green, thereby throwing away at least half of what is considered the benefit of pyro.

Im not opposed to a digital negative either. It would certainly lessen my level of hypocrisy seeing as I keep a vegan diet but until someone invents a 150 megapixel camera with a 9 stop dynamic range for the price of my RZ67, I will stick with film.

So sulfite isn't soluble in TEA?

 

[Alan Johnson]

I found with my PGK 005 with APX-100 the time (30 min 70F ag 10s each min) is about 2.5 times longer than that for PMK Pyro:
http://www.unblinkingeye.com/Articles/Developers/Times_PMK/times_pmk.html
10 min with 1:2:50 may be too short. There are formulas with glycin that work quicker at this pH,see TD-107 0n p117 of the film developing cookbook, but they are more concentrated and it is not clear if adding some metol back would affect the evenness provided by the glycin. How to make this stuff go faster is a real puzzle.
As to the question if pyro can produce flat mid-tones,well that would make a good thread on its own.

 

[Alan Johnson]

I just noticed on the unblinkingeye table,if working at 1:2:50 reduce times to 3/5ths normal.This would give for PGK 005 30x 3/5 = 18 mins 70F.

 

[mikemarcus]

A few things Alan. Firstly I was considering 1:1:50 in order to keep the same amount of activator but doubling the concentration of the developer. Lets see what happens. I guess a lot will change once my testing is finished and I have optimised the ratio of glycin to pyro and amount of sufite to add.

Also my question about the midtones was whether you had noticed that they were flatter with PGK than they would have been with either pyrocat or PMK?

By the way. Why PGK 005? Does the number refer to the version? Should my next tweak be 006?

 

[Alan Johnson]

OK, I will test with minimal agitation in 1:1:50,probably with Adox 50, a film I know to give good edge effects.I will look for unevenness vs Pyrocat HD.
I have not noticed flatter midtones with PGK, I have not printed enough to tell, it's probably just incompetence with this electric machine.005 was just an arbitrary number,IMO you have the rights to PGK Pyro for your final version if any.

 

[gainer]

Ordinary sulfite doesn't dissolve in TEA or glycol worth a hoot. You probably know that HC110 uses an organic form of sulfite, but I don't know where to get it. IIRC, it is described as a diethanolamine-sulfur dioxide complex. Maybe Dow could put you on that track. I have found the ascorbic acid to do the necessary job. I don't know which part of HC110 prompted Kodak to warn us to destroy shoes on which HC110 stock gets spilled, but I wanted to stay away from copying as much of HC110 as I could. I use it, however. If you figure a way to bubble SO2 through TEA, you ... never mind.

 

[mikemarcus]

Alan: I dont want rights to a developer. I guess the next forulation will be 006 then

Patrick: Dont destroy your shoes, send them to me.

Im off to test toe speed at different g/p ratios

 

[gainer]

I'm from West Virginia. How did you know I wear shoes?

 

[Alan Johnson]

Here is the result of a minimal agitation test with 120 film.
First,IMO for 120 film minimal agitation,stainless steel reels are better than plastic Paterson System 4 reels (which I used for this test as I have 3)as they are less prone to airbells and streaking.Better results than here should be possible.
I took 645 photograps on FP4 EI 64,a general view including the ground then shots of the sky with the same exposure.Repeated this on a second roll.Both rolls were given a 2 min presoak and developed:
(1) Pyrocat HD 1:1:100 minimal agitation 18 min 70F Agitate 1 min then 10s every 3 min.
(2) PGK 005 1:1:50 minimal agitation 24 min 70F Agitate 1 min then 10s every 3 min.
The tanks were rapped on the bench after agitation to try to dislodge air bubbles.

In printing ,corrections were made to give a good print from the general view neg.A typical sky neg was then given the same correction but darkened to simulate burning in.This shows up any unevenness.

Most of the Pyrocat HD negs were nearly perfect (a few show marks near the edge) but it is just possible to make out a lighter line at the right hand side ,which corresponds to the part of the negative near the top of the reel.(left attachment).
Most of the PGK 005 negs show blotches (two were nearly perfect).These again are on parts of the neg near the top of the reel.(right attachment)

Whatever the cause of the blotches,Pyrocat HD seems better at avoiding them with minimal agitation.

 

[mikemarcus]

hmm, so increasing the amount of reducer isn't the solution to decreased developing times. I might have to accept that this is a very slow working developer and hope that the results justify the extra time taken to develop negs. Alternatively I could try seeing how increased temperatures affect development.

I noticed that the PGK image shows very pronounced edge effects. There seems almost to be a halo round the treetop which seems much sharper and more tonally defined than it does in the other image. Also grain seems to be more pronounced than with Pyrocat-HD. Alan: Are these differences between the two images a function of developer or other factors such as printing or exposure/focus in-camera?

I'm not going to have much time for further work on PGK over the next week as I have submissions to make for two exhibitions. What little testing I managed over the weekend showed that as the ratio of Glycin/Pyro increases, there is an appreciable change in the look of the negative from soft and smooth to sharp and punchy. A good range seems to be about 3.5-6g Glycin/200ml stock A. This is quite interesting. I wonder if this can be built into the system so that changing the ratio between A & B takes advantage of this.

 

[Alan Johnson]

It is interesting that you think the Glycin works in that fashion.
I have not made any large silver prints to attempt to find differences in edge effect,so I cannot say.
I made a couple of photomicrographs to compare the grain of APX 100 with my PGK pyro 005 and Pyrocat HD. They are of pieces of negative about 0.2 mm across.Not a lot in it at first sight.

 

[Alan Johnson]

Btw Patrick, I believe metaborate cannot be used as the Part B of Pyrocat as it reacts with the Pyrocatechin giving a product of low developing activity.Perhaps using TEA in the Part B might fix this to give a lower pH developer if it was wanted to make Pyrocat with lower pH.

 

[gainer]

Btw Patrick, I believe metaborate cannot be used as the Part B of Pyrocat as it reacts with the Pyrocatechin giving a product of low developing activity.Perhaps using TEA in the Part B might fix this to give a lower pH developer if it was wanted to make Pyrocat with lower pH.

I have been doing it anyway. I just did a test of HP5+ 35 mm using a Pyrocat PC in glycol A solution and a Kodalk, or at least Borax-hydroxide B that I concocted because of my hard water that was precipitating CaCO3 all over the place. I say "a" Pyrocat PC because the paraminophenol came from Tylenol by using a little TEA + water as with Pyrocat MC. I knew the non-carbonate B would work because I had used it with Pyrocat MC. I wasn't sure about the Tylenol proportions. I used 6 500 mg tabs, crushed and soaked in a few ml of TEA and about 1/2 tbs of water, to make 500 ml stock in glycol, with 4 g ascorbic acid.

Now that I think about it, I think I remember (that is one of my most used phrases now that I have reached the age of 80) looking up a combination of borax and OH that would give about the pH of the carbonate B. At any rate, I know where to find the table in the CRC handbook. I don't think it's much different from the PMK B, which is pretty well saturated, but it may have some more OH in it.

 

[Alan Johnson]

I thought the experimental pyrocatechin developer mentioned in the last paragraph here, which did not work with metaborate was Pyrocat HD A solution.Must try it sometime.
http://www.groups.google.com/group/rec.photo.darkroom/msg/1fb652f0656cff82

 

[Alan Johnson]

Quick test on TEA as a B solution.
As the Haist theory predicts,using Pyrocat HD part A and metaborate part B 1:2:100 30 min 70 F produced an exceedingly faint image on APX 100.
But using Pyrocat HD part A 1 part, TEA 10 parts, water to 100 parts 30 min 70F agitate 10s/min produced good negatives.The 10% TEA solution has a pH slightly less than metaborate by my pH paper. Effects of TEA on grain and acutance are untested.

 

[sanking]

Quick test on TEA as a B solution.
As the Haist theory predicts,using Pyrocat HD part A and metaborate part B 1:2:100 30 min 70 F produced an exceedingly faint image on APX 100.
But using Pyrocat HD part A 1 part, TEA 10 parts, water to 100 parts 30 min 70F agitate 10s/min produced good negatives.The 10% TEA solution has a pH slightly less than metaborate by my pH paper. Effects of TEA on grain and acutance are untested.

The basic issue is that pyrocatechin needs a very high working pH. The threshold of activation is about pH 10.0. If you use secondary reducer the pH requirement drops a bit, but not a lot.

What Pat has done is mix metaborate (which gives a solution of abut pH 9.2, with hydroxide (which gives a solution of about 13.0). My pH values are very rough. In any event, the mix gives an accelerator with enough pH to fully activate pyrocatechin.

Sandy King

 

[gainer]

What you can do with metaborate and hydroxide, either sodium oe potassium, you can also do with borax and hydroxide. Proportions will be different, of course, but the borax is easier to get in most places. The hydroxide may not be so easy to get, but the Chemistry Store can supply it. Get enough to make the extra shipping cost worthwhile. The proportions can be found by experiment if you have a way to measure pH, or from a table in the CRC handbook. Probably other places as well. As I said, I needed something that would let me use the hard water from my well. It's a 30 mile round trip to get demineralized water, and stores close around here. With the non-carbonate B, I can use the well water, which is good for my bones as is. A travelling salesman tried to sell me a water softener for only $1800 (that was several years ago). When he told me how much calcium was in my drinking water, I showed him my bottle og calcium pills saying "You mean I've been paying good money for these pills that I could have saved?" He gave up.

 

[gainer]

The www.borax.com site for sodium metaborate gives pH=12 for a 15% solution by weight. Hutchings was able to make a 30% solution for PMK B (300 g/l of B). Do we need higher pH than that in the B solution? In my test of the Pyrocat PC using Tylenol for the p-aminophenol, I used 1:1:50 with whatever was in my bottle labelled "Non-carbonate B for Pyrocat". I didn't measure the pH of the working solution, but I shall.

One thing to remember is that my Pyrocats are in a sense 3 agent developers, in this case p-aminophenol, ascorbate and catechol. The ascorbate here was reacted with a bit of TEA and water while making up the A solution. The theory here is that the p-aminophenol (or Meto or Phenidone as the case may be) together with the C and the alkali act to generate enough metallic silver to act as a catalyst for the catechol. It may be that this combination does not need as high a pH even as HD without the C.

This version of PC is more like MC in that I used the alkali TEA to separate the p-aminophenol from Tylenol. I would use this approach if I had used p-aminophenol HCl, but if I use the base, the TEA treatment is not needed, nor is it when Phenidone is used, as Phenidone, C and catechol are all sufficiently soluble in glycol.

 

[gainer]

What I was trying to say was that if you make a little batch of Pyrocat HD using a bit of sodium ascorbate in stead of sodium sulfite or bisulfite, you might find that the B from PMK would suffice. I know from experience that I can make a developer from Phenidone, ascorbate and borax. If a small amount of that developer were to stimulate a larger amount of catechol in solution to act in similar fashion to Pyrocat HD, I think we would learn something.

 

[mikemarcus]

I know little about such things but according to the following discussion, borax and catechol form a reaction product which interferes with development:

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=003RPC

 

[gainer]

First time.

So, what cannot happen did happen. That does not seem to be unusual in photography. I did in fact use a borate with catechol, and got a potent developer with the normal amount of stain for a sulfite-free catechol developer. The borate was sodium metaborate. Whether it was 4 mol or 8 mol is immaterial according to the www.borax.com site, as one becomes the other at a certain temperature without change of weight. In other words, if I call the 4 mol M4, the 8 mol is 2(M4). If it deactivates catechol, it was not apparent in my test. It may be that Ryuji's statement was in regard to catechol as primary agent, or it may be that I made a mistake. There's a first time for everything.

 

[sanking]

So, what cannot happen did happen. That does not seem to be unusual in photography. I did in fact use a borate with catechol, and got a potent developer with the normal amount of stain for a sulfite-free catechol developer. The borate was sodium metaborate. Whether it was 4 mol or 8 mol is immaterial according to the www.borax.com site, as one becomes the other at a certain temperature without change of weight. In other words, if I call the 4 mol M4, the 8 mol is 2(M4). If it deactivates catechol, it was not apparent in my test. It may be that Ryuji's statement was in regard to catechol as primary agent, or it may be that I made a mistake. There's a first time for everything.

I can not say for sure that borates deactivate catechol. Some studies have apparently shown that it does, but I don't know the specifics of those studies. Perhaps they were made with catechol as the only reducer.

However, I can say for sure that a 30% sodium metaborate solution, when used with Pyrocat-HD as it is used in PMK, 1:2:100 dilution, does not provide enough pH to activate the developers. You get an image, but a very slight one. And this is true with Pyrocat whether the secondary reducer is metol or phenidone. I have not tested this with ascorbic acid as third reducer.

In your tests where you mixed borate and hydroxide, I am wondering if was not the hydroxide doing all of the heavy lifting? I mean by that, pyrocatechin requires a pH of about 10.9 to be fully activated. Perhaps it does not matter what you use an an accelerator in terms of mix so long as you get the necessary pH. Perhaps it is possible to use more metaborate in the solution and get to a pH of 10.9, but would that have any advantage over the carbonate solution?

Sandy

 

[Alan Johnson]

The TEA version of PGK Pyro,given below,has no K. It is much more active than my previous PGK 005 and I used it with the times for PMK Pyro diluting 1:100.
However, it has a serious problem with uneven development.
Agitating at 15s intervals I obtained underdeveloped spots on the negative.Continuous agitation with another manufacturers film produced the spots shown in the attachment.
I am inclined to return to the water based type of PGK pyro.
Is it true it took Gordon Hutchings 10 years to develop PMK Pyro?
TEA 80ml
Glycin 2.5g
Pyrogallol 10g
Dissolves with stirring at 150F
TEA to 100ml