Mixing Pyrocat-HD in Alcohol

[berntln]

I would like to mix Pyrocat-HD powder version from Photographers Formulary with alcohol instead of water to make the stock solution last for years.

I have read that Propylene Glycol is supposed to be used as alcohol.

However, since I don`t have a reliable supplier of pure Propylene Glycol I would like to use denatured Ethanol instead.
The denatured Ethanol that I have available has Methylisobutylketone (mibk) and Methyletylketone (mek) as denaturing agents, and it is advertized as 99,9% Ethanol and also being waterfree.

Do some of you know if that should work?
.

 

[Andrew O'Neill]

I'm not sure but at least the Phenidone will go in solution easier It is inert so probably ok.

 

[Raghu Kuvempunagar]

Heating ethanol could be risky.

 

[randyB]

If you are in the USA, you can try Tractor Supply. They have it at my local store (TN) $29.95 for a gallon jug. If you are not in the USA, try a farm supply company. Propylene Glycol is used in some animal feeds.

 

[randyB]

I just checked it is now $34.95 (https://www.tractorsupply.com/tsc/search/propylene glycol?

 

[Alan9940]

I buy propylene glycol in 1 liter bottles from Amazon. No idea if it's "pure" or not, but I've never had any issues with it.

 

[Murray Kelly]

PE suggested that it is wise to check the denatured alcohol for suitability by dropping a few drops into water and observe if there is any precipitation or cloudiness where they mix.
Any cloudiness can show up on negatives as spots.

 

[berntln]

Thank you all, I am in Norway and shipping liquid is not an option. Maybe I should give the Ethanol a chance, obviously being careful when heating. I have a magnetic stirrer, that helps getting it mixed.I wonder if the quality of the developer will be altered, and also if it will keep for years. I will try it out and report back.​

 

[Ian Grant]

My experience is Pyrocat HD mixed with distilled/de-ionised water lasts 3 to 4 years once mixed, the extra cost of the Glycol just isn't worth it.

Ian

 

[destroya]

I use distilled water, like Ian suggests. if you are worried about the developer going bad, then just mix up a smaller amount of Part A. I usually mix up 200ml a batch and its still good even if I dont finish it in 18 months. B will last much much longer, so need to worry about it, but I mix up the same amount of each to keep it simple and mentally fresh. the Catchetol will keep for many years in the freezer, at least mine has. I keep it double zip lock bagged with my metol.

keep it simple and just mix up smaller amounts. no need to buy the glycol. I bought some, used it for 2 batches and went back to water based. still have the large jug of glycol.

john

 

[pentaxuser]

I buy propylene glycol in 1 liter bottles from Amazon. No idea if it's "pure" or not, but I've never had any issues with it.

OP the above experience echoes that of John Finch the presenter of Pictorial Planet videos who buys his propylene glycol from Amazon and uses it for his phenidone for exactly same reasons in his Pyrocat HD

pentaxuser

 

[grainyvision]

Propylene glycol here is easily and cheapily available in 1 gallon quantities and food grade purity. It is used to keep baked goods moist and to make breads such as muffins shiny. I've seen some other people in EU upload labels wondering "is this the right glycol" and the name was a little different. Can't remember what the name was, but it was a german source. If you can't find propylene glycol, you may try to find ethylene glycol. These are both pretty much photographically inactive, but ethylene glycol is very toxic. Make sure to keep it far away from pets or children! Heating it is maybe a bit more dangerous as well, but exposure to its vapors seems to be minimally dangerous compared to ingestion.

 

[Raghu Kuvempunagar]

OP: I saw your other thread on TEA. Since you now have access to viscous TEA, you may consider using it as the solvent for making Pyrocat. You will still need Carbonate as the accelerator as TEA by itself will not provide the alkalinity for Catechol, but you can avoid unnecessary risks by using TEA as the solvent if you don't want to use water.

 

[john_s]

Propylene glycol here is easily and cheapily available in 1 gallon quantities and food grade purity. It is used to keep baked goods moist and to make breads such as muffins shiny. I've seen some other people in EU upload labels wondering "is this the right glycol" and the name was a little different. Can't remember what the name was, but it was a german source. If you can't find propylene glycol, you may try to find ethylene glycol. These are both pretty much photographically inactive, but ethylene glycol is very toxic. Make sure to keep it far away from pets or children! Heating it is maybe a bit more dangerous as well, but exposure to its vapors seems to be minimally dangerous compared to ingestion.

wiki is a good place to find the alternative names for chemicals. it lists half a dozen for propylene glycol.

 

[Murray Kelly]

If you really get stuck ethylene glycol is sold very pure for antifreeze. It almost always has denaturants in it to hide the sweet taste (like denatured alcohol).
My 1L can was about 1200g / L and reasonably cheap.
It has been used illegally in one European country in wine one year when the sun stopped shining and the grapes didn't ripen. They got a smack for that.

 

[esearing]

My experience is Pyrocat HD mixed with distilled/de-ionised water lasts 3 to 4 years once mixed, the extra cost of the Glycol just isn't worth it.

Ian

Age of the phenidone comes into play. A kit from PF might be all fresh chemicals or have sat on a shelf for 3 years. Glycol keeps the phenidone working a little longer. Sooner or later the kit will let you down. Better to mix yourself from fresh chems or mix only what you need for a couple of months.

 

[Ian Grant]

Age of the phenidone comes into play. A kit from PF might be all fresh chemicals or have sat on a shelf for 3 years. Glycol keeps the phenidone working a little longer. Sooner or later the kit will let you down. Better to mix yourself from fresh chems or mix only what you need for a couple of months.

There are two issues here. The age of the Phenidone unless poorly stored makes no difference it keeps very well and for a long time, I have some manufactured in 1961 that still works perfectly. The more important issue is how old is the Formulary kit and the crucial chemical is the Sodium Metabisulphite that needs to be reasonably fresh, Sodium Bisulphite is less effective, it is not the same compound.

It's the Pyrocatechin that oxidises first and it's the Sodium Metabisulphite in Part A that prevent it oxidising, over time the Metabisulphite breaks down to Sulphite, that takes around 3 to 4 year when mixed in water.

The problem of mixing in Glycol is the Sodium Metabisulphite won't dissolve in it so needs to be dissolved in a little water, this won't alter keeping properties, but you also need to mix this developer in Glycol when weighing out the fresh chemistry.

Ian

 

[berntln]

PE suggested that it is wise to check the denatured alcohol for suitability by dropping a few drops into water and observe if there is any precipitation or cloudiness where they mix.
Any cloudiness can show up on negatives as spots.

Thank you for the info, I will try that
Bernt

 

[berntln]

If you really get stuck ethylene glycol is sold very pure for antifreeze. It almost always has denaturants in it to hide the sweet taste (like denatured alcohol).
My 1L can was about 1200g / L and reasonably cheap.
It has been used illegally in one European country in wine one year when the sun stopped shining and the grapes didn't ripen. They got a smack for that.

Yes, I get the antifreeze version locally, but it has got anti-rust additives, and then I am skeptical.
Bernt

 

[berntln]

Propylene glycol here is easily and cheapily available in 1 gallon quantities and food grade purity. It is used to keep baked goods moist and to make breads such as muffins shiny. I've seen some other people in EU upload labels wondering "is this the right glycol" and the name was a little different. Can't remember what the name was, but it was a german source. If you can't find propylene glycol, you may try to find ethylene glycol. These are both pretty much photographically inactive, but ethylene glycol is very toxic. Make sure to keep it far away from pets or children! Heating it is maybe a bit more dangerous as well, but exposure to its vapors seems to be minimally dangerous compared to ingestion.

I found a Pharmacy in Oslo Norway where I live supplying Propylene Glycol 100% which I trust for its purity, but it was very expensive. Maybe I will go for that.
Bernt

 

[berntln]

OP: I saw your other thread on TEA. Since you now have access to viscous TEA, you may consider using it as the solvent for making Pyrocat. You will still need Carbonate as the accelerator as TEA by itself will not provide the alkalinity for Catechol, but you can avoid unnecessary risks by using TEA as the solvent if you don't want to use water.

I thought initially that TEA would boost the alkalinity just like it does with 510-pyro, why wouldn't it?
Bernt

 

[berntln]

There are two issues here. The age of the Phenidone unless poorly stored makes no difference it keeps very well and for a long time, I have some manufactured in 1961 that still works perfectly. The more important issue is how old is the Formulary kit and the crucial chemical is the Sodium Metabisulphite that needs to be reasonably fresh, Sodium Bisulphite is less effective, it is not the same compound.

It's the Pyrocatechin that oxidises first and it's the Sodium Metabisulphite in Part A that prevent it oxidising, over time the Metabisulphite breaks down to Sulphite, that takes around 3 to 4 year when mixed in water.

The problem of mixing in Glycol is the Sodium Metabisulphite won't dissolve in it so needs to be dissolved in a little water, this won't alter keeping properties, but you also need to mix this developer in Glycol when weighing out the fresh chemistry.

Ian

Thank you for this info! I will mix the Sodium Metabisulphite in a little water before adding it to the rest. What do you mean by ".. but you also need to mix this developer in Glycol when weighing out the fresh chemistry" ?
Bernt

 

[Raghu Kuvempunagar]

OP: TEA is also an alkali but not strong enough alkali to accelerate the activity of Catechol, the main reducing agent of Pyrocat. Hence, Sodium Carbonate or Potassium Carbonate is required in the working solution of Pyrocat. In case of 510-Pyro, the main reducing agent is Pyrogallol which has significant activity at the lower pH provided by TEA. So no need for a stronger alkali like Sodium Carbonate.

 

[Murray Kelly]

Curiously the anti-rust in antifreeze for motors is usually benzotriazole BTA. It protects the copper.

 

[berntln]

OP: TEA is also an alkali but not strong enough alkali to accelerate the activity of Catechol, the main reducing agent of Pyrocat. Hence, Sodium Carbonate or Potassium Carbonate is required in the working solution of Pyrocat. In case of 510-Pyro, the main reducing agent is Pyrogallol which has significant activity at the lower pH provided by TEA. So no need for a stronger alkali like Sodium Carbonate.

OK, I understand, I may use no water at all, only TEA when mixing, like I did when mixing the 510-pyro, is that so?
Bernt