It surprises many people that a single thangka can take anything from two weeks to more than six months. The work starts long before any colour goes on. The cotton canvas is stretched and coated with a mix of chalk and glue, then polished with a smooth stone until the surface is even. Next the painter draws the figure using a strict grid of proportions, because every part of a deity, from the eyes to the fingers, follows measurements set out in old texts.

Colour is applied in thin layers, starting with the background and moving towards the figure, and the mineral pigments have to be ground and mixed by hand. The slowest stage is the fine line work and shading on faces, clouds and jewellery, often done with brushes of just a few hairs. Buy authentic thangka painting with this in mind: the size, the amount of gold and this level of fine detail explain most of the difference in price between pieces.

So a quick, cheap thangka is rarely a bargain; the hours are visible in the result.