cassion

Cassion refers to a type of decorative plasterwork or stucco commonly found in architectural contexts. It is characterized by its sculpted relief forms, often featuring intricate patterns, motifs, or figural elements. This technique was particularly popular during periods such as the Renaissance and Baroque eras, where it was used to embellish interior and exterior surfaces of buildings.

The creation of cassion involves applying layers of plaster, typically a mixture of lime, sand, and sometimes marble dust, over a prepared surface. Skilled artisans would then mold, carve, and shape the wet plaster to achieve the desired designs before it hardened. This allowed for a high degree of customization and artistry. Common applications include ceilings, walls, cornices, and façades.

The term "cassion" can also sometimes be used more broadly to describe any decorative element that is recessed or indented, especially within a ceiling structure. In this context, it refers to the coffers or panels that make up a coffered ceiling. These recessed areas can be plain or, more elaborately, decorated with painted designs, stucco moldings, or even gilding. The visual effect of cassion work, whether in relief or as recessed panels, is to add depth, texture, and a sense of grandeur to an architectural space.