Over 2,000 years ago, gold- and silversmiths developed a variety of techniques, including using mercury like a glue to apply thin films of metals to statues and other objects.

They developed thin-film coating technology that is unrivaled by today's process for producing DVDs, solar cells, electronic devices and other products and used it on jewels, statues, amulets and more common objects. Workmen over 2000 years ago managed to make precious metal coatings as thin and adherent as possible, which not only saved expensive metals but improved resistance to wear caused from continued use and circulation.

Understanding these sophisticated metal-plating techniques from ancient times could help preserve priceless artistic and other treasures from the past.

Gabriel Maria Ingo, Senior Scientist at the Institute for the Study of Nanostructured Materials of the National Research Council of Italy, and colleagues point out that scientists have made good progress in understanding the chemistry of many ancient artistic and other artifacts — crucial to preserving them for future generations. But big gaps in knowledge remained about how gilders in the Dark Ages and other periods applied such lustrous, impressively uniform films of gold or silver to intricate objects. 

Ingo's team set out to apply the newest analytical techniques to uncover the ancients' artistic secrets. Using surface analytical methods, such as selected area X-ray photoelectron spectroscopy and scanning electron microscopy combined with energy-dispersive spectroscopy on Dark Ages objects such as St. Ambrogio’s altar from 825 AD, they say that their findings confirm "the high level of competence reached by the artists and craftsmen of these ancient periods who produced objects of an artistic quality that could not be bettered in ancient times and has not yet been reached in modern ones."

Credit and link: 
DOI: 10.1021/ar300232e

Citation: Gabriel Maria Ingo, Giuseppe Guida, Emma Angelini, Gabriella Di Carlo, Alessio Mezzi, and Giuseppina Padeletti, 'Ancient Mercury-Based Plating Methods: Combined Use of Surface Analytical Techniques for the Study of Manufacturing Process and Degradation Phenomena', Acc. Chem. Res., Articles ASAP July 5, 2013 DOI: 10.1021/ar300232e