The breakthrough came from appreciating the fact that because in Galileo's time ink was only made, sold and bought in small quantities at a time, the recipe for the ink in different pots would vary, if only very slightly. If the ink on a dated domestic document can be shown to be identical with the ink on a scientific script, then the date of the script is also known - to within a day or so, at least, sufficient for the historians' needs. The Italian National Museum in Florence holds Galileo's undated documents on, for example, celestial motions. Professor Pier Andrea Mando, of the local university, compares ink on two sets of documents by sending fast protons into the inks. The protons excite the ink atoms into emitting X rays, and the pattern of X rays emitted depends on the recipe of the ink used.
Identical patterns mean the same ink was used, so undated and dated documents are contemporary.
Using the basic physics technique for analysing materials just outlined, scientists at the university of Genoa are collaborating with colleagues in Florence to analyse the nature and concentrations of atmospheric pollutants collected by special filters. Materials in paints give off X-rays, which tell Professor Papparlado exactly what the paints were made from. Then the conservation specialists can get to work. Analysis of paints and materials in old paintings Paintings and frescoes are among the great treasures of the Italian Renaissance. Professor Guiseppe Papparlado of Catania University, Sicily, uses a transportable physics probe to analyse the paints and materials of frescoes, as an aid to restoration.