Re: Pyro redevelopment


Sil Horwitz (silh@iag.net)
Sun, 24 Jan 1999 18:32:09 -0500


At 10:11 AM 1999/01/24 -0400, Sandy King wrote:

>>This still doesn't explain Sandy's results. As a matter of interest, Sandy,
>>why is there bromide in your bleach?
>
>Quite frankly I don't know exactly what the bromide does but it is
>recommended in the formula of several super proportional reducers that I
>have on hand. I am going to assume that its primary function is to restrain
>the heavier silver deposits and reduce overall density, but this is only
>speculation.

In most bleaches, there is an oxidizer to produce a reactive silver ion,
and a receptor (like bromide) to combine with the ion immediately to form
silver halide (silver bromide if there are bromide ions present). Silver
halides, of course, can then either be dissolved in fixer, or made to
further react with another substance (as is done in toning).

Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/



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