FARMER'S REDUCER

[Philippe-Georges]

Good evening,

Sorry for disturbing, but this is really a question for the chemical wizards on APUG and I happen to need an rather clear answer.
Can I use POTASSIUM HEXACYANOFERRATE (II) TRIHYDRATE purum K4[Fe(CN)6] - 3H2O to mix op some Farmer's reducer and/or the bleach for Thiourea Toner?
I toughed, and I might be wrong, that I needed the Potassium Ferricyanide K3Cr2(CN)6, but, by mistake (?) I ordered 500 gr. of the above mentioned product.
And what is the difference?

Thank you,
Philippe

 

[Ole]

You need Potassium Hexacyanoferrate(III), also known as Potassium Ferricyanate, K3[Fe(CN)6].

The difference between Ferri and Ferro; and between (III) and (II) may seem small, but it is vital.

 

[Philippe-Georges]

Dear Ole,

Thank you for the swift answer!
But what can I do with the 1/2 Kg of Potassium Ferrocyanate I happen to have now?

Thanks again,

Philippe

 

[Mike Wilde]

consider an upgrade to ferri?

Not sure if this is feasible here, but I have regenerated bleaches that have gone ferri to ferro in E-6 and C-22 Ferri bleach work sone time ago with the controlled addition of (perhaps pottasium oxalate) a compound (as I cannot recall what was contributing the electron to upgrade the oxidation stae of the iron). It was done, as a kind of replenisher - so many grams were added per roll of film bleached. This would only work for a time until the bromide that was also a component of the bleach would build to unaccepable levels.

Search for regenerating bleaches. I think it was a kodak pro lab publication - it could be done a few ways, and the addition of an oxidizer was the lowest capital cost way, but by far the least efficient.