William Henry Jackson, Wet Plate Pyro developer and use it with modern emulsion

[Mustafa Umut Sarac]

Can anyone tell me , is there a use for 19th century wet plate pyro developers with modern emulsions ? Can we deduce them to today use ? What would be the result looks like ?

Umut

 

[Gerald C Koch]

By pyro I assume you mean pyrogallol and not pyrocatechin (catechol). The problem with this developing agent is its high toxicity. The LDLo, lowest lethal dosage is only 28 mg per kilogram of body weight. This chemical attacks the liver, kidneys, bone marrow and nervous system. In addition it is easily absorbed through the skin from its solutions. The toxic effects are also cumulative. When working with the solid, a respirator, goggles and nitrile gloves are mandatory.

Let me put the toxicity of this chemical in perspective. The great mystery writer Agatha Christie was an authority on poisons. She wrote a book about them. Her favorite means of dispatch in her books was arsenic usually in the form of the trioxide. This chemical has a LDLo very close to that of pyrogallol.

If a staining developing agent is desired I would suggest using catechol, which is less toxic.

 

[MDR]

It should work with modern emulsions, plenty of pyro developers from the dry-plate era are still in use today. And I guess that the first dry plate developers were based on wet-plate developers and did work. Dry plate emulsions and modern film emulsion are both silver gelatine emulsions.
Regarding the toxicity of pyro yes it's toxic so be careful while handling the stuff. BTW the EU does not consider it an overly toxic substance but a health risk.

 

[desertrat]

Somewhere I have a list of wetplate pyro formulas. If memory serves, these were acidic and intended for collodion negatives containing residual silver nitrate. When gelatin dryplates were introduced, the developer formulas became alkaline. Wetplate pyro formulas might not work properly or at all with modern emulsions containing no residual silver nitrate.

 

[Gerald C Koch]

Regarding the toxicity of pyro yes it's toxic so be careful while handling the stuff. BTW the EU does not consider it an overly toxic substance but a health risk.

Interesting, usually the EU seems to err in the opposite direction.

 

[MDR]

Gerald when I tried Sandy King's Pyro Uno I had to buy Pyrogallol and TEA no problem with the Pyro but I had to fill out a several pages long form and had to provide a copy of my passport to get the TEA. TEA is a component in a not so friendly weapon though only one of several and one of the least important ones at that.

 

[Gerald C Koch]

Gerald when I tried Sandy King's Pyro Uno I had to buy Pyrogallol and TEA no problem with the Pyro but I had to fill out a several pages long form and had to provide a copy of my passport to get the TEA. TEA is a component in a not so friendly weapon though only one of several and one of the least important ones at that.

Here in the US I can buy drums of the stuff without any problem. It is a component of many hand creams and lotions.

http://www.chemistrystore.com/Chemicals_S-Z-Triethanolamine.html

 

[MDR]

That's exactly what I told the lady at the counter and she said it doesn't matter the UN has put it on the list of ingredients to make weapons and the EU in it's hate for all things chemical used it as excuse to make it harder for people to buy the stuff.