From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 04/11/03-02:00:36 AM Z
----- Original Message -----
From: <rurmonas@senet.com.au>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, April 11, 2003 2:09 AM
Subject: Gold Chloride Acidity
> I was looking through some of my old books last night and
found a reference
> saying that the commonly available form of Gold Chloride
was Gold Sodium Chloride.
> The Gold chloride available these days is the acid form.
It was also mentioned
> that a strongly acidic toner formula will not tone as well
due to the gold
> being in a different ionic state. So do I need to convert
the acidic Gold
> Chloride to a salt form before use, or is a 1% dilution
enough to stop the acidity
> affecting the toner?
>
> Thank you,
>
> Richard
> ---
> Richard Urmonas
> rurmonas@senet.com.au
>
Curios. The Photo-Lab-Index both 1943 and 1964 editions
define Gold Chloride as AuCl3 HCl 4H2O Molecular weight
412.10 AKA Chlorautric acid, Gold Trichloride acid,
Hydrochlorauric acid.
I was able to find Gold Sodium Chloride for sale by
searching using Google but did not find a formula or any
other information.
The formulas I have for toners for both silver-gelatin and
POP seem to specify gold chloride as defined above.
I suspect the pH of the toner is very little affected by
the small amount of Gold Chloride in it. However, I am not a
chemist so can't be sure.
--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com How old is the book?
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