Note 252 — Chapter XV · (XXIX.)

This is a point attended to by the best modern workers in mosaic. Where gold backgrounds are used it is advisable to carry the gold into the figures by using it as Vasari suggests for the lights on the draperies. If this were not done the figures would be liable to tell as dull masses against the more brilliant ground. The use of gold backgrounds is specially Byzantine. The earlier mosaics at Rome and at Ravenna have backgrounds of blue generally of a dark shade, which is particularly fine at Ss. Cosma e Damiano at Rome and in the tomb of Galla Placidia at Ravenna. The mosaics at S. Sophia at Constantinople of the sixth century had gold backgrounds, and this is the case also with all the later examples in Italy from the ninth and tenth centuries onwards. The finest displays of these varied fields of gold, now deep now lustrous of hue, are to be seen in S. Sophia, S. Marco at Venice, and the Cappella Palatina at Palermo.

Vasari’s account of the fabrication of the gilded tesserae required for this part of the work is quite clear and agrees with modern practice. The gold leaf is hermetically sealed between two sheets of glass by the fusion of a thin film over it. The technique of the ‘fondi d’ oro,’ or glass vessels adorned with designs in gold, found in the Roman catacombs, was of the same nature.