Re: Selenium toning Kallitypes - dilution factor

Quoting Sandy King <sanking@clemson.edu>:

> My supposition is that a 1:100 dilution of selenium will not tone to
> completion and is not very archival. You could check by bleaching for
> about 10 minutes in a working solution of Kodak R-14 Reducer. For
> best understanding of what happens take reflective readings of the
> test print before and after bleaching.
>
> I would not attempt a stronger solution of selenium until you
> completely process the print, and perhaps even wait a day or so after
> it drys. It should not in theory bleach back very much after fixing,
> but if this is indeed happening in your case you might need a
> stronger fixer.

My undestanding of selenium toning is that it requires a silver solvent
to assist the conversion to silver selenide. As the size of the silver
"grains" in a kallitype are much smaller than for silver-gelatine, the
bleaching may be a result of the silver being dissolved faster than it can
be converted to silver selenide.

Richard

-- 
Richard Urmonas