Pyro-Uno

[sanking]

This is kind of a work in process

Here is the tweaked Pyro-Uno formula.

Pyro-Uno
TEA (Triethanolamine) 80 ml
Ascorbic acid 1.4 g
Pyrogallol 3.4 g
Metol 0.4 g

TEA to make 100 ml

Mix chemicals in order listed. I mix with a hot plate stirrer at about 150F. Be patient as it takes a little time for the chemicals to dissolve

Working Solution: 1:50 to 1:200. 1:100 was used for the tests with FP4+.

Remember, this is a one-solution formula that you merely mix with water for the working solution. That is why the uno, which means one in Spanish.

I adjusted the formula to give a developer which when used at a dilution of 1:100 would give a curve very close to that of Pyrocat-HD used at 1:1:100. My testing is based on development in BTZS type tubes with constant, but gentle, agitation.

In BTZS testing five sheets of film are given identical exposures and then developed for a range of times. After the film is dry the negative step wedges are read with a densitometer and the values put into Winplotter. With Winplotter one can then run the program with different print exposure scales to calculate development time for a range of subject brightness conditions. For the testing here I set the ES to 1.35, which I find about right for printing with VC silver gelatin papers.

When you look at the charts you will see that each curve has four numbers. They are from left to right, 1) time of development, 2) effective film speed, 3) average gradient, and 4) SBR (subject brightness range).

The two tests were made with a different light source so the effective film speed is comparatively speaking not 100% correct. Also, the B+F values are not indicative as the Pyro Uno tests were carried out with FP4+ film that has been stored at room temperature for about three years and has developed a small amount of B+F.


Over the next several weeks I plan to carry out some real life tests comparing this developer to D76, and will post the results as they become available.

Sandy King

 

[Lee L]

Thanks very much for sharing this Sandy. I'll be watching your reports, and maybe trying some myself.

Lee

 

[Tom Kershaw]

Sandy,

How would you compare this developer from a results point of view compared to Pyrocat-HD?

Tom

 

[sanking]

Thanks very much for sharing this Sandy. I'll be watching your reports, and maybe trying some myself.

Lee

Hi Lee,

Thanks. I plan to first test it against D76 1:1. That is what I did when I first started working with the Pyrocat-HD formula. D76 is the standard against which all developers must be evaluated for speed, grain, resolution, shelf life and apparent sharpness.

Sandy King

 

[sanking]

Sandy,

How would you compare this developer from a results point of view compared to Pyrocat-HD?

Tom

In terms of image quality I have no idea at this time. I really don't expect image quality to be any better, but the fact that this is a one solution developer may appeal to some, and the stain of pyrogallol based developers offers a bit more highlight compensation than that of pyrocatechin based developers with VC silver gelatin papers. In that sense Pyro-Uno would be more a replacement for PMK or other pyrogallol based developers than Pyrocat.

I adjusted the formula so that the energy level of Pyro-Uno would be as close as possible to that of Pyrocat-HD, for two reasons. First, my belief is that if the energy level is approximately the same with a given type of development, given the fact that the reducer amount is very similar, I would expect fairly similar results in terms of grain and apparent sharpness. And 2), if time of development for a given average gradient is nearly identical this will make any comparisons of grain and sharpness very easy since I just expose and develop both developers the same way. The most important factor in making fair and objective comparisons of developers is to expose and develop so that both give the same density and contrast.

Sandy King

 

[claudiosz]

A pair of questions
May I suppose 20ºC as development temperature in your test?
May I suppose 35% more time developing 120 film agitating 5 sec. / 25 sec. stand?
Many thanks
Claudio Sz

 

[sanking]

A pair of questions
May I suppose 20ºC as development temperature in your test?
May I suppose 35% more time developing 120 film agitating 5 sec. / 25 sec. stand?
Many thanks
Claudio Sz

My standard time for development i 21C. And I would only increase time about 20% going from continuous to intermittent agitation every 25 seconds.

Sandy King

 

[gainer]

So, if you succed, all we will have to decide is whether we want the cat or the gal.

 

[PhotoJim]

What sort of shelf life do you expect for the stock solution?

 

[sanking]

What sort of shelf life do you expect for the stock solution?

The shelf life of a stock solution mixed in TEA should be at least 2-3 years unless the solution is contaminated. The same is true of stock solutions mixed in glycol. This is because because the solutions do not oxidize as they might if mixed in water.

Some people have suggested that such solutions might last for decades. I have some doubts about this because all of the solutions I have mixed in TEA, including Gainer's original PC-TEA, have strongly discolored after three or four years. I also have a small container of another single solution pyro developer that I mixed in TEA several years ago and the color, which was very clear on mixing, has also strongly discolored in the three or four years since I mixed it. I don't know the cause of the discoloration but tend to believe it is caused by oxidation.

Sandy

 

[eclarke]

I wll give this a go on the weekend. I always expose 2 sheets for backup and development options and right now I have about 100 second sheets at my disposal.. Should be fun..Evan Clarke

 

[sanking]

So, if you succed, all we will have to decide is whether we want the cat or the gal.

That is one way of putting it. At this point in my life a new cat would be a lot less expensive than a new gal.

But a one-solution developer makes a lot of sense for some people. You would be surprised how many people are simply unable to get it right when mixing two part developers like PMK and Pyrocat-HD. Folks have found more ways to screw up than I ever might have imagined!!

Sandy

 

[mikebarger]

I think some of it is the routine you're used to. When I decided I wanted to try a pyro developer I was using HC110 mixed straight from the bottle. To be honest, that's about the only reason I chose 510 Pyro over any of the two solution pyro developers. Seems like at the time it was the only one solution pyro I had heard of.

Not a very good reason for selection of one developer over the other, but at the time it seemed worthwhile. I suspect there are others that will try this mixture based on the one bottle.

Mike

 

[gainer]

Well, with two parts plus water, there are at least 3 things to screw up, and 3 factorial (6)possible outcomes only one of which is the desired one.

With regard to high viscosity, I have found that the Chemistry Store, which is about the cheapest place to get a gallon of TEA, also sells containers including Boston rounds of various sizes and lotion pumps to fit. The lotion pump is the best way I have found to move small quantities of gooey stuff from the container to a graduated cylinder. Each stroke of the pump moves about 1/2 ml. You don't have to use the full stroke. I see they are out of stock in white pumps but have others. Another place to look is www.sks-bottle.com.

 

[gainer]

TEA is hygroscopic. The weight gain at equilibrium is 20% at 50% humidity, 25% at 60% humidity . Perhaps that is another way a lotion pump can help. It would minimize contact with air while decanting from storage. If the TEA solution is heated to 250F not long before storage, it ought not have much water in it initially.

50% humidity is not uncommon in these parts.

 

[john_s]

TEA is hygroscopic. The weight gain at equilibrium is 20% at 50% humidity, 25% at 60% humidity . Perhaps that is another way a lotion pump can help. It would minimize contact with air while decanting from storage. If the TEA solution is heated to 250F not long before storage, it ought not have much water in it initially.

50% humidity is not uncommon in these parts.

50% humidity is actually fairly low. I know that APUG members live in all sorts of climatic extremes, but in a temperate climate the outside humidity is often 60% to 90%. When you have the heating on the relative humidity inside becomes less, even though the absolute humidity is unchanged. I wonder if it's the relative humidity or the absolut humidity that is relevant in the case of TEA based developer absorbing water from the air, a little bit every tme the bottle is opened.

For this reason and because of possible oxidation I generally don't use the last bit of developer in the bottle, if it's a highly concentrated type which takes many openings of the bottle to use up.

 

[mikebarger]

When I mix the 510 pyro I put it in small enough bottles that I can use it up fairly quickly (months). When I get down to the end of the bottle I turn it upside down over the next bottle for a couple hours after making the first batch from the new bottle. What little is left I don't worry about.

Sandy's brew could be handled the same way.

I don't think I'd want to be using a TEA developer out of a two liter bottle.

Was the pump strokes pretty consistent in the amount they delivered with each stroke? If you're getting .5ml per stroke and need 10ml, would the 20 strokes introduce to much variability batch to batch?

Mike

 

[gainer]

I'm attaching the figure from the Dow specs.

 

[gainer]

I don't think I'd want to be using a TEA developer out of a two liter bottle.

Was the pump strokes pretty consistent in the amount they delivered with each stroke? If you're getting .5ml per stroke and need 10ml, would the 20 strokes introduce to much variability batch to batch?

Mike

Bottles with the lotion pump are available in a wide range of sizes. I'm 82 years old. I wouldn't think of mixing 2 liters for my use.

I wouldn't depend on the lotion pump for accurate measurements. I would use it to transfer from storage to a graduated cylinder. Without the pump, this is a problem. Of course, the oral dosing syringe that looks like a hypo is an alternative, but it is a bit clumsy at times. I tried using the cylinder from such a syringe, without the plunger, as a graduated cylinder. The tip must be covered and when the desired amount is in the cylinder, the tip is to be placed over the receiving vessel, the tip is opened and the plunger is reinserted to insure getting all the stuff from the cylinder walls. The obvious tip cover at the time was a fingertip, which is a bit messy and in some cases dangerous. Since the concentrate is going into water in this case, it is better to rinse the measuring cylinder with some of the contents of the receiving vessel.

 

[gainer]

TEA has another property that may be confusing. It freezes at 21.6 C, but is easily supercooled, which is the way most of us see it most of the time. I have received a jug of it that had lumps of "ice" in it. I'm sure many darkrooms are below that temperature at times.

 

[gainer]

BTW, I found on www.unblinkingeye.com a very simple pyro developer by some nut named Gainer. Must be my alter-ego. It' 7 grams of pyrogallol dissolved in 100 ml TEA, heated to drive out water. That's it. Dilute 1+50 or so and develop 10 or 15 minutes for starters. I'm out of pyro and can't order more until payday.

 

[gainer]

I found enough pyro to make a batch. You'd be surprised at how good such a simple developer can be. In a sense, it is older by far than this old man, being closely related to the Pyro-Soda developer which Hurter and Driffield admired. Soda, of course, is sodium carbonate. Here's a sample of FP4+, 1+50, 77 F. (It's warm in there.)

 

[Mahler_one]

Gainer....you can only imagine what TEA would weigh after a few hours in Florida:}.

Ed

 

[Mahler_one]

Also many thanks from this end Sandy. The comparisons with D76 will really be interesting.

Perhaps you and Gainer should develop a kit form of Pyro-Uno and sell such!?

What precautions do you use when weighing and using the Pyrogallol?

Ed

 

[sanking]

Also many thanks from this end Sandy. The comparisons with D76 will really be interesting.

Perhaps you and Gainer should develop a kit form of Pyro-Uno and sell such!?

What precautions do you use when weighing and using the Pyrogallol?

Ed

Ed,

First, about the precautions. I wear a mask and make sure that any powder that might get in to the air will go downwind from me.

Second, the amount of useful practical information Gadget has shared with our community about formulating developers for films and papers is nothing short of amazing. And in large measure, the information he has shared has been empirical data, which I find to be the most useful.

I had hoped to get out today and do some exposures for comparison testing of Pyro-Uno with D76 1:1. Unfortunately, the transmission on my old Nissan Pathfinder is causing problem and won't allow me to back up. For that reason the Pathfinder is now in the hands of a local mechanic, who to this point (three days and running) has not been able to identify the source of the problem. So here I am, stranded at home and at the mercy of my wife who has a fully operational vehicle.

Sandy