Re: silver nitrate problem

RE: (E-Mail Removed) (Janet Ness) wrote

> Having reviewed all my books which contain salted paper recipes, I
> found that Webb & Reed in "Alternative Photographic Processes" is the
> only one which includes citric acid in the sensitizing solution. The
> silver nitrate and citric acid are mixed in separate solutions with
> distilled water and then combined. Webb & Reed says that "The citric
> acid acts as a preservative and stops the silver coating from
> darkening before you can get round to printing it." The three other
> books call for just silver nitrate and distilled water , usually in a
> 12% solution. Their recipes for the salting solutions differ also,
> and include either sodium citrate or, in Barnier's "Coming into
> Focus," potassium citrate. I wonder whether the citrates in the
> salting formulas serve the same preservative purpose as the citric
> acid?

Nitrates are very oxidized. In a sulfite sense, nothing is being
preserved.
Salts of citric acid are citrates. Organic materials will reduce
silver nitrate. Darkened material will result. NO light required.
I'm not familiar with the process though it does sound time
critical. Dan


Dan Quinn