Oddy test

Agnes Gall-Ortlik <agaor [at] caramail__com> writes

>I am carrying out Oddy tests on gap-filling materials for enamels on
>metal. I have found some references in the literature describing the
>directions for setting up the test, but of those, just one gives
>information on how to evaluate and interpret the results--color
>shift, surface condition, localization and morphology and changes:
>...
>I would be thankful for any answer that would enable me to improve
>interpretation clues.

This timing of this subject is fortunate because a technical note of
visual test methods used in conservation was just published in the
March 2001 AIC News (vol. 26, no.2) pg. 10. This technical note was
written by James Martin and Dr. Chandra Reedy on behalf of the
Research and Technical Studies Group of the AIC.

In addition to the error that comes from the subjective assessment
of the test,  the test is also prone to error from the variation of
procedures used. I have witnessed this several times--in one
instance a conservator handled all of the metal coupons with their
bare fingers and in another instance tap water was used. All coupons
used must be uniform in size (surface area) and should be properly
cleaned, degreased, and not contaminated before testing. Likewise
all of the test tubes need to be similarly cleaned. This lack of
rigor in performing the test preparation and procedures and the
variance in interpretation make this test an extremely general
indicator only. I would never use the results of an Oddy test alone
as a citation in a publication.

Barbara Appelbaum mentions the use of fill materials that are tested
and have long standing in the field. I have always believed that it
would be most useful to pass from the general use of the word
"tested" and be as specific as possible about the test methodologies
and results that indicate a positive performance for the material.

The field of conservation will never be considered a science until a
set of standards are in place as to testing methods and the
repeatability of results. This is why every conservator, no matter
their specialty, needs to support and keep informed as to the
activities of groups such as Research and Technical Studies (RATS).

David Harvey
Conservator of Objects
The Art Conservation Center at the University of Denver
2420 S. University Blvd.
Denver, CO  80208
303-733-2712


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                  Conservation DistList Instance 14:50
                 Distributed: Wednesday, March 28, 2001
                       Message Id: cdl-14-50-001
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