Chemical Clues to the Mystery of What Covers Stradivari’s Violins

Stradivarius violins produce elegant music with a level of clarity unmatched by modern instruments, according to some musicians. And it’s the finishing touches – mysterious treatments applied hundreds of years ago by Antonio Stradivari – that contribute to their unique look and sound. In a step towards unlocking the secret, researchers from Analytical Chemistry report on nanoscale imaging of two of Stradivari’s violins, revealing a protein-based layer between the wood and the varnish.

Previous studies have reported that some string instruments made by Stradivari have a hidden coating under the gloss varnish. The purpose of this coating would have been to fill and smooth the wood, influencing the resonance of the wood and the sound produced. Knowing the components of this film could be the key to reproducing historical instruments in modern times.

Thus, Lisa Vaccari, Marco Malagodi and their colleagues wanted to find a technique that would determine the composition of the layer between the wood and the varnish of two precious violins, the San Lorenzo 1718 and the Toscano 1690.

Using a technique previously used on historic violins, synchrotron radiation Fourier Transform Infrared Spectromicroscopy, the team found that both samples had an interlayer, but this method could not differentiate the composition of the wood layer. adjacent. They then turned to near-field scanning infrared scattering microscopy (IR s-SNOM) to analyze the samples.

The s-SNOM IR device includes a microscope that collects images tens of nanometers wide and measures infrared light scattered from the coating layer and wood to collect information about their chemical composition. Results from the new method showed that the layer between the wood and the varnish of both instruments contained protein-based compounds, coming together in nano-sized patches.

Since the s-SNOM IR provided a detailed 3D image of the types of substances on the surface of the violin, the researchers say it could be used in future studies to identify compounds in complex samples of multi-layered cultural heritage. .