The Conservation Department at the Fortress of Louisbourg in Cape Breton, Canada, was recently asked by our Collections/Archeological department if we could find a product to replace fingernail polish for the numbering of mass amounts of objects collected during archeological digs, the majority of which are ceramic and glass fragments. The office space used to number each piece has poor ventilation. This isn't a problem when numbering just a few pieces, but the fumes accumulate when numbering hundreds of pieces at a time. Unfortunately, we do not have the funds necessary to improve ventilation. During this search we came across a product from Golden Artist Colors called Porcelain Restoration Glaze (PRG) available in gloss or matte formulation. The label lists it as a reversible water-based coating used to repair fine porcelain objects.

Initial tests showed, while it dried slower than fingernail polish, the difference was very slight especially when mass numbering. Both PRG gloss and fingernail polish had similar appearances when dried. Both were easily soluble in acetone but not ethanol. Further, long term immersion in water showed PRG dissolved while fingernail polish simply lifted off of the substrate. A comparison of costs show both are available for similar prices.

The MSDS sheets obtained from Golden Artist Colors reveal the only active ingredient is a small amount of ammonia, which has a vapor density heavier than air. During its testing no fumes were noticed even after numbering 50 to 100 objects at a time.

Although originally the alternative was needed solely for numbering ceramic and glass pieces preliminary tests show the PRG causes no harm to copper, iron, and lead which are the metals most commonly found here at the Fortress of Louisbourg.

For ease of use the PRG was placed into cleaned fingernail polish bottles and was applied with a brush. Numbering was found to work best using acrylic inks. We noticed other inks did not appear to adhere as well to PRG and would sometimes start to lift as a topcoat was brushed on if they did not have enough time to fully set.

While these tests are just the first step, this product shows considerable promise as an alternative to the more tradition fingernail polish in numbering museum and historic site collections.