Well, That's Odd-y: The Basics of the Oddy Test

Well, That's Odd-y: The Basics of the Oddy Test

If you've worked in museums and archives for a long time, you've probably heard about the Oddy Test. The Oddy Test is a way for museums and archives to check if certain materials are safe for use around valuable or delicate items, like old documents, artwork, or historical objects.

The test was invented in 1973 by William Oddy, a British conservation scientist working at the British Museum. It helps ensure that storage boxes, display cases, and frames don't release harmful chemicals that could damage these sensitive items over time.

How It Works

  1. Testing the Material: A small piece of the material (like plastic or fabric) is placed inside a sealed container.
  2. Metal Samples: Small pieces of silver, lead, and copper are also inside the container. If harmful chemicals are released, these metals can react.
    1. Silver detects reduced sulfur compounds and carbonyl sulfides.
    2. Lead detects organic acids, aldehydes and acidic gases
    3. Copper detects chloride, oxide and sulfur compounds.
  3. Heat and Moisture: The container is heated up, and some moisture is added, which speeds up the process.
  4. Check for Damage: After about a month, the metal pieces are checked. The material is safe if they are still shiny and look the same. If they are corroded or tarnished, the material could be harmful to artifacts.

In simple terms, if the metal doesn't get damaged, it is safe to use around historical items. If it does, it could cause damage and shouldn't be used. This test is similar to the accelerated aging test for materials used to store photographs, the Photographic Activity Test (P.A.T.).

Limitations

  1. Interpreting the testing results is subjective and involves visually inspecting the metal pieces, so different testers may interpret the same results differently.
  2. There isn't a standard across institutions that limits variables such as glassware cleaning, metal preparations, reaction vessel setup and rating criteria.
  3. The test only indicates that something is potentially damaging, but does not identify what specific compound is causing the issue. 
  4. The test takes 28 days to complete, making it impractical when results are needed quickly.
  5. The materials used to create the tested materials can be changed by the manufacturer at any time. Testing will need to be conducted when the material composition changes.

Benefits

  1. The Oddy Test is low-cost and simple. It uses basic laboratory equipment and materials, making it accessible to institutions of all sizes.
  2. The testing replicates 5-6 years of natural aging in 28 days, allowing conservators to predict possible long-term effects of materials on artifacts.
  3. The testing can be done on various materials, including wood, paints, adhesives, fabrics, plastics and foams.
  4. It is widely used in the conservation field by institutions such as the J. Paul Getty Museum, the Nelson-Atkins Museum of Art and the Metropolitan Museum of Art. Its results are used globally to evaluate the suitability of materials for storing and displaying cultural heritage artifacts.
  5. While the test is nonspecific about the compound causing the issue, that can be a benefit as well. You don't need a science degree to know that the material damaged the metal pieces.

Despite its limitations, the Oddy Test is crucial for conservation. It is valued for its simplicity, low cost, and ability to detect contaminants. Efforts have been and will continue to be made to improve the process but the test is still an important way for institutions to test the impact of materials on the long-term preservation of objects.


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