RED PIGMENTS
Vermilion, Rose Madder, Scarlet Madder, Alizarin Crimson, Crimson Lake, Carmine, Indian Red, Light Red, Burnt Sienna.
Vermilion is one of the most important colours for the illuminator. It is prepared from sulphide of mercury. There are various kinds, which are termed Orange Vermilion, Scarlet Vermilion, Vermilion Extract, Vermilion, etc. Probably that known simply as Vermilion is most useful to the illuminator.
Most vermilions are manufactured in this country, but that known as Chinese Vermilion is imported from China.
Although vermilion is indispensable to the illuminator, it cannot be guaranteed as being absolutely permanent. Cennino Cennini, writing about this pigment, says: “But remember that vermilion is not durable when exposed to the air; it is more lasting on pictures than on walls, because, by long exposure to the air, it becomes black when applied to walls.”
It is a fact that vermilion does change in this way, but it is debatable whether it is affected by the air. It is thought by some that the action of the sun’s rays is a more likely cause of change. There are two varieties of mercuric sulphide, the red and the black; unfortunately the red is liable to change into the black. No chemical change is necessary for this, as they are both identical from a chemical standpoint. In the diffused light of a room this colour seems to be quite permanent, but it is liable to turn black suddenly when exposed to direct sunlight. There is conclusive proof that vermilion, when not placed so that the rays of the sun come into direct contact, is quite permanent by the fact that in the illuminated MSS. produced centuries ago the vermilion is still bright.
Most authorities are of the opinion that genuine Chinese vermilion is more permanent than the English variety. There are two methods employed at the present day in the manufacture of this colour—the wet and the dry process. The dry method is used in China and the other in Europe. The wet method is more economical, but it is generally admitted that vermilion produced by the dry process is more permanent than the other kind. Unfortunately the Chinese vermilion that is obtainable in this country is often rather poor in quality.
Rose Madder and Scarlet Madder are lakes prepared from the madder root. These are very beautiful colours and are permanent under ordinary conditions. They should not, however, be exposed to direct sunlight.
Alizarin Crimson is a permanent crimson with a coal-tar origin.
Crimson Lake and Carmine are lakes prepared from cochineal; they are quite fugitive and should not be employed for serious work.
Indian Red is a variety of iron oxide and is permanent.
Light Red and Burnt Sienna are prepared by burning Yellow Ochre and Raw Sienna; they are both quite permanent.