American scientists analysed wood shavings from two old violins being repaired and found a chemical wood preservative in their backboards.
The research found that the maple wood had been treated with salts of copper, iron and chromium – a wood preservation technique used in the areas of Italy where the great violin makers worked.
The scientists believe the salts could have altered the acoustic properties of the instrument.
Lead researcher Joseph Nagyvary, of Texas A&M University, has done several previous studies on Stradivarius violins, including work which showed that borax used by Stradivari to prevent woodworm improved the sound of the instruments.
