Gesso

Furthermore, gesso can help to extend the life of a painting by acting as a barrier to protect it from moisture, dust, and UV rays.

For priming flexible canvas, an emulsion of gesso and linseed oil, also called "half-chalk ground", is used.

Acrylic gesso can be odorous, due to the presence of ammonia or formaldehyde, which are added in small amounts as preservatives.

[8] Sculptors may use gesso to prepare the shape of a final sculpture (fused bronze) or directly as a material for sculpting.

[9] In this case, a layer of refined and coloured clay called bole is used to cover the gesso before applying the gold.