From: Joachim (joachim@microdsi.net)
Date: 03/08/02-12:01:48 PM Z
Contact papers were all silver chloride and silver bromide was introduced
because of the need for faster (more light sensitive) papers for enlarging.
The characteristics of the anions attached to the silver cation determined
other characteristics as well, light sensitivity is just one. Chloride
papers tend to have a much broader tonal range than bromide papers, and Agfa
added AgCl to its bromide to give us those wonderful, now discontinued,
papers that made such rich portraits. These days when I want to make a
really rich silver print I contact print while my supply of Azo paper lasts.
One major impetus for the shift to digital printing is that the technology
of silver printing is imploding. It is obvious that the immediate future of
fine art photography resides in the digital world. Change is neither good or
bad, change is amoral, but it is that, change. Joachim
> -----Original Message-----
> From: Gregory W. Blank [mailto:gblank@bellatlantic.net]
> Sent: Friday, March 08, 2002 9:46 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Sabatier, theory, myth, etc.
>
>
> on 3/8/02 8:33 AM, Joachim at joachim@microdsi.net wrote:
>
> > Can I hazard a guess (that's all it is) on the warm-tone cold-tone paper
> > question? The difference may reside in the chemistry in that warm tone
> > papers are generally higher in their chloride/bromide ratio than colder
> > papers that are usually all bromide? Joachim
> >
>
> As for the ratios of chemical in the paper? Who knows most paper
> manufactures don't give out the formulas. However it is fairly safe for me
> to say ChloroBromide papers have more "Salt" than Bromide papers.
> Bromide papers have more Bromide which cools and makes the papers
> faster.
>
> Referring to my knowledge of Bromofort paper vs Fortezo (Chlorobromide
> graded).
>
> The Fortezo (Warm "chlorobromide") was / is about two stops slower.
>
> I may also note that if anyone on this group would be interested
> in getting
> Bromofort paper which was available until about two years ago I possibly
> can get/ on special order basis. The paper I understand was good
> for Bromoil
> process.
>
>
>
>
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