Dear Sian,

Here is a follow up on your question about how artists were able to paint once the sinopia was covered with plaster.......

It is important to know when a fresco was painted. Frescoes you will find in the sinopia museum in Pisa are from the early 1300'. Frescoes which date before the mid 1400's had to deal with the issue of limited access to large sheets of paper. It was expensive and depending on the amount of money provided for a project determined whether an artist could afford it
or whether they chose to incur this expense.

Large sheets of paper inable an artist to enlarge drawings to scale to use as a refernce when working and also they are able to make transfers,or spolvero, which allows an artist to transfer an image directly onto the velo. Artists would also glue these large sheets together to make even bigger sheets of paper.
Michelangelo wrote of garzoni glueing sheets of paper together to prepare for his fresco "The Battle Of Cascina." It is recorded that he had the entire mural drawn and maped out for this mural. Pretty big!!!

For the artist working in the earlier times, they would first paint the entire mural on the arriccio using a reddish paint made from a clay which comes from syria. The preliminary painting was named after the paint...."Sinopia." Artists would carefully lay plaster to fit an exact portion of the painting.All work painted on the velo at this point is from memory and from using drawings as reference to the information underneath. Because artists were not bound by strict transfers, one sees a departure from the sinopia and with that which was actually painted. Some areas are faithful to what was planned in the sinopia. Other areas depart completely..sometimes omitting figures or adding figures.

Studying sinopias has shed light that artists before the Renaissance had a better understanding of perspective and the rendering of forms three diminsionally. Many of the early sinpoias are as interesting as the actaul frescoes and are also works of art in themselves.

Hope this has helped.

Sincerely,

Mozart