Tested toner recipes

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Tested toner recipes

Post by shinryuu » Thu Jun 29, 2006 2:50 pm

The recipes on digital truth for the toners.
Have anyone tested the blue toner?
If you add acid to potassium ferricyanide you get cyanide gas, right.
In the recipe, it says, add acetic acid. So that's why I'm asking.

I guess, the potassium and the ferric citrate has already reacted with each other. But if it were some potassium left that didn't react some cyanide gas might be made, couldn't it.

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Post by Digitaltruth » Thu Jun 29, 2006 5:47 pm

I have used this toner myself, but a long time ago.

While you are correct that ferricyanide and acid produce cyanide gas, this will not occur if you follow the instructions and always add the chemicals to water in the correct sequence. It is common for many darkroom formulas to use combinations of potassium ferricyanide and different acids, but you must only ever add acid to ferricyanide that is already in solution.

What you must never do is mix powder ferricyanide with any acid, so it is particularly important to carefully wash any toner from your tray and sink when you are finished to avoid it drying out or crystallizing back into a powder form.

When mixing chemicals it is always advisable to wear rubber gloves, protective eyewear and a dust/gas mask. I strongly recommend following these simple precautions.

The blue toner formula is identical to one published by Ansco as Iron Blue Toner #241
Digitaltruth Photo

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