PREPARING FERRIC OXALATE
POWDER
(by Vicente-M. Vizcay Castro, August/1999)
(American English adaptation by Jeffrey
D. Mathias)
Introduction
The procedure of preparing Ferric Oxalate
powder is believed to be of great interest to the alt-photo community.
We consider that knowledge must be shared, not hidden, not used to one's
own advantage or in one's own interest. In June 1999 Vicente-M. Vizcay
Castro asked if his powdered ferric oxalate could be tested and the preparation
procedure added to this Guide. After testing and verification of
the procedure, the ferric oxalate powder was found to be of the highest
quality and full instructions published here within.
Ferric oxalate is a sensitizer for some
of the iron based photographic processes. The dry powder form is desired
because of its superior storage characteristics. It is therefore an advantage
for one using such a material to be able to make it themselves from readily
available materials and commonly available low cost equipment.
The "modus operandi" has been adapted so
as not to require specific laboratory equipment and to allow for the use
of low-cost elements. Efforts have been made to maximize the details of
the evolution of the reaction and the subsequent processes. The most
tedious phases are those with the purpose of removing the water and nitric
acid from the precipitate.
The cost of the ACS grade reagents can
be about 0.13$/g of FO powder when ordering from Alfa-Aesar (this may be
even less from another manufacturer or when purchasing larger quantities).
Other suppliers or buying in smaller quantities can cost more.
Testing
and Information
This preparation procedure has been verified
by Jeffrey D. Mathias (click
here for some notes).
The Ferric Oxalate (FO) produced by this
procedure has been tested and compared with other FO powder. FO powder
produced by this procedure was found to be of the highest quality.
Acknowledgments
The author of this Guide gives acknowledgment
and a multitude of thanks to Vicente-M. Vizcay Castro for developing and
allowing publication of this procedure in this Guide; to Eric Neilson for
his efforts to test FO powders (Eric's results and verification of the
preparation procedure are not ready at this time, but will be added when
complete.); to John Melanson and the writings of Richard Sullivan for information
on mixing stronger concentrations of FO using EDTA; to Dick Stevens' book,
"Making Kallitypes" for the conversion of specific gravity into solution
concentration percentages for FO. The illustrative digital photographs
and drawing were made by Vicente-M. Vizcay Castro.
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IMPORTANT ---------------------------------------------------------
These instructions are only for personal use.
No commercial or any derived advantage of them are permitted. No
express or implied license for use exists.
No part of these instructions may be distributed,
reproduced, republished, or stored in a retrieval system, or transmitted
in any form or by any means (electronic, mechanical, photocopying, recording
or otherwise) without the express written permission of the author, Vicente-M.
Vizcay Castro.
free