Oddy test

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The Oddy test is a procedure created at the British Museum by conservation scientist William Andrew Oddy [1] in 1973, [2] in order to test materials for safety in and around art objects. Often, materials for construction and museum contexts (including artefact conservation) are evaluated for safety. However, though materials may be safe for building purposes, they may emit trace amounts of chemicals that can harm art objects over time. Acids, formaldehyde, and other fumes can damage and even destroy delicate artifacts if placed too close.



This test calls for a sample of the material in question to be placed in an airtight container with three coupons of different metals—silver, lead, and copper—that are not touching each other or the sample of the material. [3] The container is sealed with a small amount of de-ionized water to maintain a high humidity, then heated at 60 degrees Celsius for 28 days. An identical container with three metal coupons acts as a control. If the metal coupons show no signs of corrosion, then the material is deemed suitable to be placed in and around art objects. The Oddy test is not a contact test, but is for testing off-gassing.

A basic layout of a three-in-one Oddy Test Oddy-test-color.jpg
A basic layout of a three-in-one Oddy Test

Each metal detects a different set of corrosive agents. The silver is for detecting reduced sulfur compounds and carbonyl sulfides. The lead is for detecting organic acids, aldehyde, and acidic gases. The copper is for detecting chloride, oxide, and sulfur compounds.

There are many types of materials testing for other purposes, including chemical testing and physical testing.


The Oddy test has gone through many changes and refinements over time. Whereas Andrew Oddy proposed to place each metal coupon in a separate glass container with the material to be tested, Bamberger et al. [4] proposed a "three-in-one" test, where all three metal coupons shared one container, simplifying the procedure. Robinett and Thickett (2003) [5] refined the "three-in-one" test by stabilizing the metal coupons.

One of the main issues with the Oddy test is that there is some subjectivity to the interpretation of the results, [6] since it is primarily a visual determination.

Oddy-tests 0823b Oddy-tests 0823b.jpg
Oddy-tests 0823b

Institutions that use the Oddy test in their research are mainly art museums such as The J. Paul Getty Museum, The Nelson-Atkins Museum of Art, and the Metropolitan Museum of Art.

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William Andrew Oddy, is a former Keeper of Conservation at the British Museum, notable for his publications on artefact conservation and numismatics, and for the development of the Oddy test. In 1996 he was awarded the Forbes Prize "for outstanding work in the field of conservation" by the International Institute for Conservation, and gave the attendant Forbes Lecture that year in Copenhagen. He retired in 2002 and was appointed as an Officer of the Order of the British Empire the same year.

Flowers of sulfur tests

Flowers of sulfur (FOS) testing was developed to determine the porosity of metallic coatings susceptible to sulfur induced corrosion [see below ASTM B809-95(2018)]. Applicable substrates are silver, copper, copper alloys and any other metal or metal alloy with which sulfur will react. For porosity testing, coatings can be single or multiple layers of any metal that is not corroded and sealed by a self-limiting reaction in the reducing sulfur environment of the FOS test. The simplest recommended technique is to identify any porosity of the coating as revealed by the presence of surface spots. These surface spots form where the environmental sulfur has penetrated and reacted with the base metal, producing a metal sulfide. Chalcocite, copper (I) sulfide is dark-grey to black. Silver (I) sulfide is also grey-black.


  1. "Archived copy". Archived from the original on November 23, 2008. Retrieved May 4, 2011.CS1 maint: archived copy as title (link)
  2. W.A.Oddy, "An unsuspected danger in display", Museum Journal 73, 1973, p.27-28
  3. Schiro,Mara "Oddy Test Protocols" http://www.conservation-wiki.com/index.php?title=Oddy_Test_Protocols&oldid=4830 Accessed February 6, 2012.
  4. Studies in Conservation, Vol. 44, No. 2 (1999), pp. 86-90.
  5. Studies in Conservation, Vol. 48, No. 4 (2003), pp. 263-268.
  6. "Standard Materials for Corrosiveness Testing". 11 January 2011.

Further reading