Other colours described are those known as “folium” colours. These seem to have been different vegetal dyes.
In Chapter XL. he gives a description of how to prepare ink. This is quite different from the ink of the classical period, which, as mentioned before, was made from lampblack and gum-water. The ink described by Theophilus is more of the nature of our modern writing-ink, being prepared from the bark of thorn-trees, amounting really to an infusion of tannin, with the addition of iron sulphate, popularly known as green vitriol.
There is no mention in this MS. of the preparation of ultramarine.
Following this there are the MSS. that have been translated by Mrs. Merrifield, viz., Eraclius, Alcherius, the book of Peter St. Andemar, all included in the MSS. of La Bègue, the Sloane MS., and the Strassburg MS.
The MS. of Eraclius is regarded as not being later than the thirteenth century, the first two books being very early and quoted by Theophilus.
In these MSS. it is plainly stated that the colours were generally mixed with either gum-water or egg. White of egg was often used, but occasionally the yolk. For example, it seems to have been used as a medium for vermilion and orpiment. These MSS. contain a lot of information very similar to that in the MS. of Theophilus.
Lakes were, in the earliest MSS., prepared in a similar way to that used in the classical period, and are described in this manner in the MS. of Eraclius. In the MS. of Jehan le Bègue, however, there are several recipes that have been compiled by him from the MSS. of Alcherius, of the fourteenth century, which are practically the same as the modern method.
The MS. of Le Bègue is also of interest, as it contains a recipe for the preparation of real ultramarine.
Perhaps the most interesting MS. of all is that known as the Book of the Art of Cennino Cennini. This is a most delightful treatise on the methods then in use. Cennino Cennini was an Italian painter and was living in Padua in 1398. The MS. in the Vatican is dated 1437, but this is in all probability merely the date attached by the copyist. It is evident that the colours and methods that he mentions were in use during the fourteenth century.