Craquelure (French: craquelé, Italian: crettatura) is the fine pattern of dense “cracking” formed on the surface of materials, either as part of the process of aging or of their original formation or production. The term is most often used to refer to tempera or oil paintings, where it is a sign of age that is also sometimes induced in forgeries, and ceramics, where it is often deliberate, and usually called “crackle”. It can also develop in old ivory carvings, and painted miniatures on an ivory backing are prone to craquelure.
There are distinct so-called French, Italian, Flemish, English and Dutch “styles” of craquelure, relating to differences in the typical techniques used (and the typical period when each country produced most of its art); however these names just refer to typical patterns, and an Italian painting might show a “French” style of craquelure. The distinctness of these styles has been largely confirmed by studies. The English style arises from the use of bitumen in paint that was pioneered by Sir Joshua Reynolds, and can be especially disastrous, leading to large blisters in the surface.
Radiating circular patterns of cracks are a result of impact. One study used images to get subjects to classify paintings according to the following “rules”, with some success: Italian – usually perpendicular to the grain of the panel; Flemish – usually ordered network; Dutch – usually connected network; French – usually curved cracks; Italian – can have small to large islands.
