While treating very old wall paintings, i was surprised to see sinopia showing up at places different from the final figure’s outline. When i studied more and more sinopia history, purpose and real examples, i learnt that the sinopia usually used to be the roughest (literally) of sketches made to fix the scale and position of the main figures in relation to the wall-space.

 History of Sinopia    (from Daniel V. Thompson, The Materialsand Techniques of Medieval Painting, p no 98)
In classical antiquity the great source of red ochres was Pontus Euxinus, and the choicest red earth came from the Pountine city of Sinope. This red was a valuable monopoly, and ancient Greek and Rome looked to Sinope to maintain the quality of its product. To guard against substitutions the colour was sold under a seal (stamped into cakes of colour, we may suppose), and was known as “sealed Sinope. In the Middle Ages the name of Sinope came to be applied to other earths of less distinction, and the Latin and Italianword Sinopia came to mean simply a red ochre. We have even an English from the same source, “sinoper,” which means the same, an earth red.

I am in the process of studying and writing more about Sinopia, the pigment as well as the process. So, all kinds of queries as well as information is most welcome at namitajaspal72@gmail.com.