Pyro-Uno

[gainer]

I worked for 30 years for NASA, retired in 1982, and am still being paid. What I did with NASA was for the good of the country and made me feel happy as well as well fed. I am in a different field in one way, but in the same field in another. I'm addicted to solving problems, some of which didn't exist before I solved them. Solving a problem, making something worth doing easier to do, hearing "Thank you", especially from my 2 1/2 year old great grand daughter, are things that keep me alive. I'm sure I'm not alone among APUGers in that respect. You know that Sandy is one of us. This is the place to tell what you know as well as what you don't know but would like to.

 

[mikebarger]

Well put Pat.

Mike

 

[Murray Kelly]

I'm attaching the figure from the Dow specs.

I usually keep the top screwed tight on my TEA. Dow don't have a timeline on the graph. As in photography, exposure time is important.
Now that you've given us a new and better way to make pyrocat-MC without TEA maybe PyroUno will remain a curiosity?
Seeing as how Sandy King has been so good as to gather and collate his formulae perhaps we can sweet-talk you into doing the same? Please?
Over the years the various brews you've given us have morphed and it can be a little confusing reading 5 or 10 year old google finds that aren't current.
Don't forget the PC-Borax along with the PC-TEA etc.
Just hoping.
Murray

 

[gainer]

Don't forget that catechol and pyrogallol give different stain colors. There are times when that makes little difference, but there are times when one color is greatly to be desired over the other, and to be able to choose the desired color without a complete change of development procedure would be a good thing. I don't think Pyro Uno should remain a curiosity. When Sandy is through with its "development" it will be a well documented system as parallel to the Pyrocat series as possible.

I do not wish to compete with anyone. Argue, yes, if it's a civil philosophical argument, but for the purpose of seeking knowledge, not ascendency.

 

[Olli J]

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

Speaking about oxidation, I made recently an unexpected finding which bothers me. About three months ago I mixed 510-pyro developer, it's in TEA as you know. To reduce viscosity I mixed the ready developer with propylene glycol 1+1. Originally the solution had a pale color. After mixing the solution was divided in two parts. Within the first week I developed some films with it and they came out fine. Since then the developer has been undisturbed on the shelve in my darkroom, in well capped glass bottle, about 100ml solution in a 250 ml bottle. A couple of weeks later I noticed that the solution had begun to darken, starting from the surface and proceeding deeper. Now it's all dark but still the solution is darker on the surface than in the bottom. To me it looks like airborne oxidation, but it started much earlier than I would have expected. The other part of the developer was used by another person, who recently reported that his developer also had dark color but still functions as well as earlier, but the "life expectancy" of this developer is not very good.

I have to admit that my pyrogallol is several years old, but it still looks good, almost white, a little sticky powder. All other chemicals are fresh. Any ideas why the solution oxidized so fast? Could there be a problem in mixing TEA and glycol?

Olli

 

[gainer]

Did you heat the TEA before mixing to drive off as much water as possible? The temperature must be above the B.P. of water, and you should stir it gently with a long handled spoon. You will see steam if it has water in it. That is not TEA vapor.

 

[Olli J]

Did you heat the TEA before mixing to drive off as much water as possible? The temperature must be above the B.P. of water, and you should stir it gently with a long handled spoon. You will see steam if it has water in it. That is not TEA vapor.

No, I did not. Could there be so much water in TEA that it makes the difference?

 

[sanking]

There may be a problem in mixing TEA with Glycol. Pyrocat-HD mixed in glycol remains clear for years. Pyrocat-MC, mixed in glycol with a small amount of TEA, darkens appreciably after one year, and more after two years. Other than the metol/phenidone difference in the two formulas, the only other difference is the small amount of TEA in Pyrocat-MC.

The fact that you mixed the 510 Pyro 1:1 with glycol may have accelerated the reaction between the TEA and glycol.

On the other hand, I have on hand a 510 Pyro solution that is several years old. It was clear for at least two years, but now has darkened considerably. It may or may not still be good, have not tested it with film recently. But as I noted earlier re: the darkened Pyrocat-MC, the fact that it is so dark makes me very suspicious that the reason is oxidation.

Sandy King

Speaking about oxidation, I made recently an unexpected finding which bothers me. About three months ago I mixed 510-pyro developer, it's in TEA as you know. To reduce viscosity I mixed the ready developer with propylene glycol 1+1. Originally the solution had a pale color. After mixing the solution was divided in two parts. Within the first week I developed some films with it and they came out fine. Since then the developer has been undisturbed on the shelve in my darkroom, in well capped glass bottle, about 100ml solution in a 250 ml bottle. A couple of weeks later I noticed that the solution had begun to darken, starting from the surface and proceeding deeper. Now it's all dark but still the solution is darker on the surface than in the bottom. To me it looks like airborne oxidation, but it started much earlier than I would have expected. The other part of the developer was used by another person, who recently reported that his developer also had dark color but still functions as well as earlier, but the "life expectancy" of this developer is not very good.

I have to admit that my pyrogallol is several years old, but it still looks good, almost white, a little sticky powder. All other chemicals are fresh. Any ideas why the solution oxidized so fast? Could there be a problem in mixing TEA and glycol?

Olli

 

[Mahler_one]

Gadget Gainer

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

I fully agree. Gadget adds so much to our discussions and general knowldege. The information that he supplies is not available easily-if at all-from any other source. Very grateful that he takes the time to help.

Ed

 

[psvensson]

I've been using MC-TEA for something like 3 years. It darkens over time, but it does so evenly, throughout the solution. If the darkening was due to aerial oxidation, I'd expect it to be strongest at the surface, given that TEA is so viscous. That's what happened with a solution I made of phenidone in propylene glycol - it went red at the surface, but stayed clear below that.

I also haven't noticed any real change in the activity of MC-TEA over time, despite the darkening, though I haven't tested this very carefully.

Put supposing activity over time is nearly intact, that plus the even nature of the darkening leads me to wonder if it is due to some slow reaction in the solution other than aerial oxidation. Perhaps it's a reaction between impurities.

 

[gainer]

No, I did not. Could there be so much water in TEA that it makes the difference?

I believe so. See the hygroscopicity chart I posted earlier. In 50% relative humidity the equilibrium weight gain is 20%. A liter of dry TEA weighs 1126 grams. In equilibrium with 50% humid air it will weigh 225 grams more. I don't really know how much water it takes to allow developers dissolved in TEA to become active. I once placed a piece of film in a saucer of PC-TEA in light and saw no response over some period of time, but do not remember how long. It was reported in my original article in Photo Techniques. You can do the same sort of experiment with HC-110 concentrate with the same results. But add a bit of water and see what happens.

 

[Kenneth Lee]

Any updates ?

 

[sfaber17]

aa turns red

I'm trying to make pyro uno and 510 Pyro. I heated the TEA fresh from a new bottle and heated it above
100C and there was no water, so then after adding the ascorbic acid it turned light red. I added the metol
which dissolved right away. By the time it cooled it was dark red. I'm not sure what the problem is?
Could I make it with sodium ascorbate?

 

[Muihlinn]

Probably tea was too hot

 

[sfaber17]

Thanks, you were right, it worked this time when I kept it cooler.
I may have had a trace of gallic acid in there which might not have helped either.
Since I didn't have any pyro but had a bunch of gallic acid left over from
pyrotechnics experiments, I made a separate batch of pyro in glycerine by heating gallic acid in
glycerine to 195 deg C. Now it is a pyro duo developer I guess.

 

[kozesluk]

Anyone here tried substituting the Metol with Phenidone?