A number of white earths were also employed, chalk being the most important. White lead was used, being prepared in practically the same way as the best is to-day. Lakes were made by dyeing chalk or gypsum. Several vegetal dyes were used for this purpose, such as madder, weld, and woad. In addition to these dyes, lakes were prepared from kermes and the celebrated murex. Kermes is a red dye caused by a small insect similar to that of the cochineal insect; it was used for dyeing and for making pigments, both in classical and mediæval times. The murex was a species of shellfish from which was extracted the famous purple dye. This was the dye used for the purple vellum that was used so much in the early period.
The blacks used were carbon-blacks, such as lamp-black, bone-black, or the black prepared from grape husks and vine leaves.
Indigo was undoubtedly in use, and it is highly probable that the red resin known as dragon’s blood was also in use. Pliny, in his “Natural History,” describes the fighting between the elephant and the dragon, and he states that the name cinnabar should be given to the thick matter which issues from the dragon when crushed beneath the weight of the dying elephant, mixed with their blood. It is thought that he may be referring to this pigment, for, in another chapter, he refers to India sending the corrupt blood of her dragons and elephants. There is one colour, which was one of the principal pigments of the Middle Ages, of which no mention is made in the classical period, and that is ultramarine.
It is difficult to be certain as to how the different colours were mixed, but the ink used was prepared from lamp-black mixed with gum and water, and it is probable that the colours were mixed with either gum, glue, or egg.
The Lucca MS. of the eighth century, in the cathedral library at Lucca, contains, amongst other things, a short list of pigments. There is very little difference between the information given here and that given by Pliny. This MS., however, gives the first distinct directions for making artificial vermilion. It is also interesting as giving definite information as to how colours were mixed for working on parchment or vellum, as the following quotation plainly shows: “On wood the colours being mixed with wax, on skins fish-glue being mixed.”
In the twelfth-century MS., the Mappæ Clavicula, the greater part of the Lucca MS. is repeated.
The Schedula Diversarum Artium of Theophilus is also of about the same date, and is a very important MS. It is divided into three books, the first dealing with painting, the second with the manufacture of glass, and the third with metal-work. It is evident that Theophilus, who was a monk in some German monastery, was a worker in metal. However, he collected quite a lot of information on various forms of art work. It is, of course, in the book on painting that the information with regard to colours is found.
In Chapter XXVII. he gives instructions for preparing the gum for mixing with colours. This is described as follows: “Take gum which exudes from the cherry or plum tree, and, cutting it up very small, place it in an earthenware pot, and pour water upon it abundantly and place it in the sun, or in winter upon the coals, until the gum has liquefied; and mix it together with a smooth piece of wood. Then strain it through a cloth, and grind the colours with it and lay them on.”
In Chapter XXXIV., which is entitled “How Colours are Tempered for Books,” he says: “Make a mixture of the clearest gum and water as above, and temper all colours except green and ceruse and minium and carmine. Salt green is worth nothing for books. You will temper Spanish green with pure wine, and if you wish to make shadows, add a little sap of iris or cabbage or leek. You will temper minium and ceruse and carmine with clear of egg. Compose all preparations of colours for a book as above, if you want them for painting figures. All colours are laid on twice in books, at first very thinly, then more thickly; but once for letters.”
Salt green, that is mentioned here, was a mixture of verdigris and subchloride of copper. Spanish green was verdigris, and minium was red lead, while ceruse was white lead. Verdigris is, of course, a notoriously fugitive colour, but while in ordinary water-colour painting it would probably not be safe to use, it would last fairly well in books. Certainly it seems to have done so in the past, if one may judge from the greens in many of the old MSS., which are still brilliant.