HOW COLOURS ARE TEMPERED FOR BOOKS.
These things thus accomplished, 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 twice for letters.
The next extract I give is of great interest in the technical history of
illumination, on three accounts: firstly, because it guides the student to
recognize in madder the purple stain and colour, so highly prized in the
early periods of the art; secondly, because it shows him the manner in
which fugitive vegetable tints were protected from the decomposing
influence of the atmosphere by an albuminous varnish; and thirdly, because
it illustrates the ordinary modern processes of under painting, and glazing
with transparent colour. The "folium" of the Greek illuminators was
procured from plants growing abundantly near Athens, while that of the
Hiberno-Saxon scribes was obtained from the "norma" or "gorma" of the
Celts. Mr. Hendrie, in his learned notes to Theophilus, has traced
successive recipes for the preparation of "folium," in which the identity
of the base giving the colouring matter is clearly established. It is
curious that the collections of "Secreta" should give as the only countries
supplying the materials for making "folium," those two in which the use of
the bright purple stain ascends to the very earliest of their decorated
manuscripts. The following is the description given by Theophilus:--