Precipitated calcium carbonate (chalk)
Gesso is a chalk foundation that artists use to prepare wood, canvas or other material for painting.
Gesso is Italian for plaster. By applying a few layers of gesso, followed by fine sanding, the surface is made smooth and even white. An additional advantage is that the next layer of paint does not pull into the cloth itself, but lies in a thin film on top.
There are different recipes for making gesso. The oldest recipe is from Cennino Cennini and dates back to around 1400. Classic recipes often use animal glue such as fish or bone glue. The primer is then applied to the cloth in a hot way so that the fabric is stressed due to shrinkage. Nowadays gesso is also for sale in pots, ready for use. Also see
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