What is a fresco?
A fresco is a wall-painting technique in which pigment, mixed with water, is applied to still-wet lime plaster so that it binds permanently into the wall as the lime cures. The Italian word “fresco” means “fresh,” referring to the fresh, damp plaster layer. As it dries, the lime (calcium hydroxide) reacts with carbon dioxide in the air to form crystalline calcium carbonate (carbonation), which encloses and locks in the pigment grains without any separate binder.
Method
The true technique is called buon fresco. The painter works on a fresh, fine lime layer known as the intonaco. Because the lime stays damp for only a few hours, only as much plaster is applied as can be painted in a single day. This day’s section is called a giornata, and the seams between giornate are often visible.
Buon fresco versus fresco secco
- Buon fresco: painting into wet lime; very durable, with a limited colour range.
- Fresco secco: painting on dry plaster with a separate binder; faster but less durable and prone to flaking.
Application
Frescoes have been used for centuries in churches, chapels and palaces, especially during the Italian Renaissance. Because the pigment is bound within the lime, they are highly resistant to ageing, provided the substrate stays dry.
Related terms
- Plasterwork
- Lime
- Stucco
- Sgraffito
- Intonaco
- Carbonation
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