<previous The Bon Fresco technique is not recommanded today in cities where the air is laden with soot and with acids produced by the burning of the sulphur in coal. In Italy the frescoes are in relative good conditions with a few exceptions: Cimabue's Crucifixion in Assisi or Leonardo Da Vinci's Last Supper which have suffered some severe decay.

In the case of Cimabue, it is believed that the use of white lead for the lights in the Crucifixion on the right, caused the blackening of the fresco¹.

Giotto experimented also with a different technique, Fresco Secco in the Peruzzi Chapel of the church of Santa Croce. This fresco faded over time as you will see in the next page.

1. cited in The Materials And Techniques of Medieval Painting. Daniel V. Thompson, Dover Book, New York, N.Y, 1956. p 96.