From: Carl Weese (cweese@earthlink.net)
Date: 06/29/00-05:30:31 AM Z
Steve Shapiro wrote:
>
> In printing photographs with silver gelatin we can use restrainers to allow
> for a brighter white, what is the element in the three solutions that allows
> for a brighter white in the Platinotype processes?
>
> Steve Shapiro, Carmel, CA
Multiple factors affect contrast. It sounds like you're using a kit
('three solutions') so it's likely the second ferric oxalate bottle
contains potassium chlorate which acts as a highlight restrainer. But,
you can use other chemicals instead of chlorate to either expand the
overall tonal scale or merely restrain highlights. In addition, changing
the ratio of Pt and Pd changes contrast, with Pt being contrastier.
Choice of paper will also influence contrast, not just through
differences in base color and dmax, but various papers interact
differently with the chemicals and have either subtle or dramatic
contrast differences.---Carl
-- Website with online galleries and workshop information at: http://home.earthlink.net/~cweese/
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