In the context of this artwork, discuss the Restoration of the History.
Although 16 concentric layers of scaffolding were erected inside the cathedral in 1979 to provide  access for the restorers it took another 10 years of research, preparation coupled with various delays before the actual restoration commenced in January 1989.
Undertaken under the supervision of Cristina Acidini the restoration officially ended in January 1994 though it took until the end of 1995 for the scaffolding to be removed. A  196 feet (60 m) high elevator provided access from the ground up to start of the restoration levels.
The project had an expected cost of $25 million.To create the fresco Vasari used the true fresco method which involved the application of pigment directly to damp lime-based plaster without the use of a binding agent as he considered it was the most virile, most secure, most resolute and durable. The downside is that this method is one of the most difficult and time-consuming to use. Pressed for time, Zuccari mostly used the in secco method, which involves painting onto dry plaster using a weak limestone solution binder. Vasari had a poor opinion of this method believing that it was not durable. His belief was confirmed as restorers found that while Vasari's frescos were virtually intact and the colours still well integrated into the plaster Zuccari's frescos had suffered a notable loss of colour and in some areas had become detached from the wall. As the principal impact on the artwork had been from dust and grime (which been deposited by smoke rising upwards from church activities) the frescoes are mostly cleaned with deionized water, which was applied in a wood-flour compress through a sheet of Japanese paper. Where the artwork was in a more fragile state only paper and water was used. The compress was left on for 20 minutes, before it was removed and the dirt carefully removed using a cotton swab.
Where Zuccari's colours had irreversibly detached themselves from the supporting wall, it was necessary for the restorers to reattach them using acrylic resins.
in secco Cristina Acidini left true fresco fresco