From: Robert W. Schramm (schrammrus@hotmail.com)
Date: 08/06/00-04:02:22 PM Z
Sandy,
A precipitate is a solid that is formed asa result of a chemical
reaction between two or more chemical compounds in liquid form.
In this case you simple mix the two liquid solutions together and
the solid will form and settle out of the solution. One then puts
a filter paper in a funnel leading into another container and pours
the whole thing (liquid and solid) into the funnel. The liquid goes
through. The solid stays behind. Then you wash the precipitate by
pouring distilled water though the funnel. What remains on the
filter paper is silver oxide.
Bob Schramm
>From: Sandy King <sanking@hubcap.clemson.edu>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>CC: silh@earthlink.net
>Subject: Argyrotype Again
>Date: Sat, 05 Aug 2000 21:59:10 -0400
>
>I have been printing with the Argyrotype Process of Mike Ware for the past
>week or so and am very pleased with the results (and consistency) on
>Fabrianto Artistico paper. The color of the prints, untoned, is a very
>attractive dark brown and contrast can be changed by adjusting the amount
>of Sulphamic Acid in the sensitizer. However, Argyrotype uses the much more
>expensive Silver Oxide rather than Silver Nitrate. Mike describes a way to
>precipitate Silver Oxide from Silver Nitrate, as follows:
>
>"Alternatively, 7 g Silver(I) Oxide may be precipitated from a solution of
>10.3 g Silver Nitrate by adding a solution of 2.5 g Sodium Hydroxide; after
>filtration and washing, the moist precipitate may be dissolved in the
>Sulphamic Acid."
>
>I don't understand the concept of a chemical being "precipitated from"
>another but I have on hand a large suppy of silve nitrate and would like to
>give it a try. Can someone explain how I would do this in practice,
>especially the part about filtering and washing?
>
>Sandy King
>
>
>
>
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