Exhibition Catalog
Mirrors During the Reinassance Period
Part 4
By Helen Costantino Fioratti
The Venetian procedure was similar to those of German and Flemish factories, which, until then, had held the secret for well-reflecting mirror glass. The Northerners also had exported mirrors for great profit, and this would prove a great resource for Venice as well. From the late fifteenth century an amalgam had been used in Germany which became the definitive method for backing the glass to create the reflection with mercury and lead. The frames into which the Venetian mirror plates were fitted became important and expensive. The authorities introduced sumptuary laws in 1489 as they considered the money spent on mirrors ‘a vain and superfluous expense’- (this also applied to polished steel mirrors as they were the usual form before the 1520’s). Venice’s many printed publications spread the styles for her luxury trades via engravings to the rest of Italy and beyond.
The Venetians had by then learned to make their glass particularly smooth and pure, finally achieving true reflection. Metal mirrors continued to be widely used however throughout the mid-sixteenth century, as described in contemporary inventories (which specifically mentioned glass mirrors as opposed to their metal counterparts).
Relatively large sized glass was being produced in Venice by the mid-sixteenth century. Venetian mirrors now surpassed all others - and finally supplanted metal mirrors. In 1572 the mirror-makeup process was published in Leonardo Fioravanti's essay Specchio di Scientia Universale. At last, these methods had produced the reflective property to create a colorless and fairly accurate mirror.
In 1507, the artisans Andrea dal Gallo and Domenico d'Angelo repeatedly asked the Consiglio del Dieci for the privilege to manufacture mirrors, “specchi di vero cristallin,” in Venice. Dal Gallo and d’Angelo were granted their license for twenty-five years.
Venice became the primary source for mirrors throughout Europe between the sixteenth and late seventeenth centuries. Catherine de’Medici (1519 – 1589) had a ‘cabinet de miroirs’, with one hundred nineteen Venetian mirrors set into paneling in her Paris apartments, an early example of a distinctive new style. She ordered another such mirror in 1572 from a silversmith named Dujardin to present to the Queen of Navarre. Her ‘cabinet de miroirs’ had a portrait of her husband the King Henri II, painted on the glass over the fireplace. Another earlier Queen, Isabella of Spain, had a silver mirror, but made in Florence in 1490 with rinceau pattern design.
Between the late Middle Ages and the nineteenth century, silvering was applied with mercury, which was much later discovered to be poisonous to the artisans, and is now outlawed. The silvering was achieved with speculum metal, an amalgam of tin and mercury. A sheet of tinfoil was laid -out free of wrinkles. A little mercury was poured onto it and rubbed over the surface. Impurities were then removed – the tin was covered with approximately one quarter inch (one centimeter) of mercury (to float the glass) onto a highly polished plate of glass. The glass then was slid onto a light cushion of liquid mercury and weighed down with rocks until the excess mercury was squeezed out around the perimeter. The mirror being produced was then placed onto a tilted rack – silvered side up, until it drained, dried and hardened for twenty-four hours.