J. Henry Middleton

“ The alcaline silicate of the glass frit acts upon the copper, which slowly combines with the glass, giving it a deep blue colour. The addition of a little oxide of tin turns it into an opaque blue enamel, which when cold was broken up with a hammer, and then powdered, but not too finely, in a mortar.
Smalto blue is largely used for the simple blue initials which alternate with red ones in an immense number of manuscripts. The glittering particles of the powdered glass can easily be distinguished by a minute examination. Like the ultramarine, the smalto blue is always applied in a thick layer. ”

“ The above-mentioned blues are all of a mineral character, and are durable under almost any circumstances. To some extent however the vegetable indigo blue was also used for manuscript illuminations, both alone and also to make a compound purple colour.
Method of using dyes. Colours of all kinds prepared from vegetable or animal substances required a special treatment to fit them for use as pigments in solid or tempera painting. Though indigo and other colours of a similar class are the best and simplest of dyes for woven stuffs, yet they are too thin in body to use alone as pigments. ”

“ One method, occasionally used for the cheaper class of manuscripts, was to paint on to the vellum with white lead, and then to colour it by repeated application of a brush dipped in the thin dye-pigment. Many of the colours mentioned below belong to this class.
Terra verde. Green pigments. A fine soft green much used in early manuscripts is a natural earthy pigment called terra verde or green Verona earth. This needs little preparation, except washing, and is of the most durable kind; it is a kind of ochre, coloured, not with iron, but by the natural presence of copper. ”

“ Vehicles used. The coloured pigments of the illuminators. Though mediaeval manuscripts are splendid and varied in colour to the highest possible degree, yet all this wealth of decorative effect was produced by a very few pigments, and with the simplest of media, such as size made by boiling down shreds of vellum or fish-bones [1] , or else gum-arabic, or occasionally white of egg or a mixture both of the yoke and the white [2] . In the main the technique of manuscript illumination is the same as that of panel pictures executed in distemper (tempera) . ”

“ It is not only the most magnificent of all blue pigments, but is also the most durable, even when exposed to light for a very long period.
Its manufacture. The general principle of the manufacture of ultramarine is very simple; consisting merely in grinding the lapis lazuli to powder, and then separating, by repeated washing, the deep blue particles from the rest of the stone [5] . The process of extracting the blue was made easier if the lapis lazuli was first calcined by heat. ”

“ Verdigris green was much used by manuscript illuminators, especially during the fifteenth century, when a very unpleasant harsh and gaudy green appears to have been popular. When softened by an admixture of white pigment, verdigris gives a pleasanter and softer colour.
Chrysocolla. A native carbonate of copper, which was called by the Romans chrysocolla [9] , was also used for mediaeval manuscripts. It is, however, harsh in tint if not tempered with white. Both the last-named pigments were specially used with yoke of egg as a medium. ”

“ In early times it appears to have been usual, or at least not uncommon, for the same hand to write the text and add the painted illuminations, but when the production of illuminated manuscripts came mostly into secular hands, the trades of the scribe and the illuminator were usually practised by different people ”

“ An oil medium was unsuited to manuscript work because the oil spoilt the beautiful opaque whiteness of the vellum and made the painting show through to the other side [3] .
Ultramarine blue. Blue pigments. The most important blue pigment, both during classical and mediaeval times, was the costly and very beautiful ultramarine (azzurrum [4] transmarinum) , which was made from lapis lazuli, a mineral chiefly imported from Persia. This ultramarine blue was the cyanus or coeruleum of Theophrastus and Pliny. ”

“ In order to keep the white pigments perfectly pure, some illuminators used to keep them under water, so that no dust could reach them.
Black inks. Two inks of quite different kinds were used for the ordinary text of mediaeval manuscripts.
Carbon ink. One of these was a pure carbon-black (modern Indian or Chinese ink) ; this has been described under the classical name atramentum librarium [17] ; see above, page 27. The great advantage of this carbon ink is that it never fades; it is not a dye or stain, but it consists of very minute particles of carbon which rest on the surface of the vellum. ”

“ Red pencil. Another kind of pencil was made of a soft red stone, which owed its colour to oxide of iron. From its fine blood-red tint the illuminators called it haematita, lapis amatista or amatito, hence an ordinary lead pencil is now called either lapis or matita in Italy. This stone is quite different from the hard haematite which was used in classical times for the early cylinder-signets of Assyria.
Burnisher. The harder varieties of the amatista or haematite were used to burnish the gold leaf in manuscripts, small pieces being polished and fixed in a convenient handle. ”

“ Iron ink. The other variety was like modern black writing ink, only of very superior quality. This acts as a dye, staining the vellum a little below the surface. Unfortunately it is liable to fade, though when kept from the light (as in most manuscripts) it has stood the test of time very well.
Sometimes the mediaeval illuminators distinguished these two kinds of black ink, calling the first atramentum and the second encaustum; but frequently the names are used indifferently for either: see Theophilus, I. 40. ”

“ This would have smudged the painting round the gold if it had been applied first. Moreover, the burnisher was liable to carry small particles of gold on to the surrounding vellum, which would have given a ragged look to the design, if the adjacent surfaces had not been subsequently covered with pigment. In cases where there is an isolated gold boss there is usually a slight disfigurement from the burnisher rubbing the vellum all round the gold. ”

“ Thus both in classical and mediaeval times these dye-pigments were prepared by making a small quantity of white earth, powdered chalk or the like absorb a large quantity of the thin dye, which thus was brought into a concentrated and solid, opaque form, not a mere stain as it would otherwise have been. ”

“ Paintings on panel, being moveable, were usually dried by being placed in the sun; but, in every way, a good drier like litharge answers better than heat, either of the fire or of sunshine.↑ See Theophilus, I. 39.↑ See Vitruvius, VII. 10 ”

“ Small horns to hold black and red ink; see fig. 53 on page 209.
Colour-box, palette, pigments, gold leaf and media of various kinds.
Sponge and pumice-stone for erasures. Paintings of scribes. Miniatures representing a scribe writing a manuscript are the commonest of all subjects in several classes of illuminated manuscripts. For example the first capital of Saint Jerome's Prologue in the historiated Anglo-Norman Vulgates almost always has a very minute painting of a monastic scribe [22] , seated, writing on a sloping desk, with his pen in one hand and his penknife in the other [23] . ”