Re: Liver of sulfur?

From: John <ap@darkroompro.com>
Subject: Re: Liver of sulfur?
Date: Sat, 01 Nov 2003 22:39:28 -0600

> On Sat, 01 Nov 2003 22:40:18 -0500 (EST), you wrote:
>
> > Polysulfide and liver of sulfur are
> > different mixtures and they are not interchangeable. Polysulfide does
> > not contain carbonate. Liver of sulfur does.

> I believe that this is the fault of the industry.

Why do you think so? Do you mean the fault of darkroom literature
industry?

Liver of sulfur is a crude material that is industrially produced by a
relatively simple process but contains multiple products. Carbonate,
etc. are naturally there as a part of the products, not added.

Liver of sulfur is the common source of potassium polysulfide but
extraction of polysulfides requires purification. For toning
solutions, presence of sulfate, carbonate, and other stuff are not
really disadvantageous, and since liver of sulfur is a lot cheaper
than purified polysulfides, liver of sulfur is most often used. As far
as I know, respectable laboratory supply companies distinguish these
two. If a company advertises potassium polysulfide but actually ships
liver of sulfur, it's definitely a problem for laboratories.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)