"Take the red skin and carefully pumice and temper it in tepid water, and pour the water on it till it runs off limpid; stretch it afterwards, and smooth it diligently with clean wood. When it is dry, take the whites of eggs and smear it therewith thoroughly; when it is dry, sponge it with water, press it, dry it again, and polish it; then rub it with a clean skin, and polish it again and gild it."
Such gilding was effected with gold leaf, beaten out between small sheets of "Greek parchment, which is made from linen cloth" (i.e. paper), enclosed in vellum. White of egg was used as the mordant for fixing on the gold.
The following two passages instruct the student in preparing gold for writing:—
"File gold very finely, put it in a mortar, and add the sharpest vinegar; rub it till it becomes black, and then pour it out. Put to it some salt or nitre, and so it will dissolve. So you may write with it; and thus all the metals may be dissolved.
"Take thin plates of gold and silver, rub them in a mortar with Greek salt or nitre till it disappears. Pour on water and repeat it; then add salt, and so wash it. When the gold remains even, add a moderate portion of the flowers of copper and bullock's gall; rub them together, and write and burnish the letters."
The next and last, alludes to the amalgam, which appears to have been for many centuries a favourite method of applying gold to parchment and other surfaces.
"Melt some lead, and frequently immerse it in cold water. Melt gold, and pour that into the same water, and it will become brittle. Then rub the gold filings carefully with quicksilver, and purge it carefully while it is liquid. Before you write, dip the pen in liquid alum, which is best purified by salt and vinegar."
In these instructions the student may distinctly recognize the processes adopted in the production of those gilt texts on stained vellum grounds which were so highly prized in the Carlovingian age.
In the writings of an ecclesiastic, probably nearly contemporary with the Norman conquest, the monk Rugerus, or "Theophilus," we arrive at a really perfect picture[[107]] of the arts of the 11th century. The first of the three books into which his "Schedule of different Arts" is divided, is dedicated entirely to painting. It contains forty chapters, of which thirty refer to the preparation and application of pigments generally, both for oil, tempera, and fresco painting, and ten to the various processes connected with illumination. Of these, the following are the most important:—
CHAPTER XXX.