[alt-photo] Re: Fluka / Sigma-Adrich Ammonium Iron(III) Citrate - contains Fe(II)!!!

[Loris Medici]

I thought the same way, OTOH, I fear to add in excess since I'm going to use for iron-silver processes too - I think that wouldn't be nice for those... I guess ferricyanide is the best test; even a small amnt. will cause prussian blue pigment that has high-tinting strength.

Regards,
Loris.

On 27.Haz.2010, at 20:52, Alberto Novo wrote:

>> 2. I'm going to test in order to find the min. amnt. of peroxide that cures the problem. (Tell me if you want it to share here later...) OTOH, I'm not sure if there's any adverse effect in adding peroxide to the stock solution, both in terms of stability and picture-making. I would definitely like to have your comments and warnings (if any) on this issue.
> 
> In the old texts (don't ask me which one, I am only remembering...) it was recommended the use of potassium permanganate in order to oxidize the iron(II). However, I don't see any adverse effect of H2O2 if you add it drop by drop, checking for the blue reaction after each drop.