Every casual variety of colour would be employed to equal purpose. Even the glass-blower’s flukes came in most usefully, not merely, as before, to break the colour of a background accidentally, but as local colour. Sheets of glass, for example, which came out, instead of blue or ruby, of some indescribable tint, streaked and flecked with brighter and darker colour, until they were like nothing so much as marble, were introduced with magnificent effect into the pillars of the architecture which now formed so prominent a feature in window design. The beauty and fitness of this marble colour is eventually such as to suggest that the glass-blower must in the end deliberately have fired at this kind of fluke.
Beautiful as were the effects of white and stain produced in the middle of the fourteenth century, it was put now to fuller and more gorgeous use. Draperies were diapered in the most elaborate fashion; a bishop’s cope would be as rich as the gold brocade it imitated; patterns were designed in two or even three shades of stain, which, in combination with white and judicious touches of opaque-brown, were really magnificent. Occasionally, as at Montmorency—but this is rarer—the painter did not merely introduce his varied stain in two or three separate shades, nor yet float it on so as to get accidental variety, but he actually painted in it, modelling his armour in it, until it had very much the effect of embossed gold.
In some ornamental arabesque, which does duty for canopy work at Conches, in Normandy, this painting in stain is carried still further, the high lights being scraped out so as to give glittering points of white among the yellow. The result of this is not always very successful; but where it is skilfully and delicately done nothing could be more brilliantly golden in effect. It is curious that this silver came to be used in glass just as goldleaf was used in other decorative painting; in fact, its appearance is more accurately described as golden than as yellow, just as the white glass of the sixteenth century has a quality which inevitably suggests silver.
It was stated just now that blue glass could be stained green. It is not every kind of glass which takes kindly to the yellow stain. A glass with much soda in its composition, for example, seems to resist the action of the silver; but such resistance is entirely a question of its chemical ingredients, and has only to do with its colour in so far as that may depend upon them.
Apart from glass of such antipathetic constitution, it is quite as easy to stain upon coloured glass as upon white; and, if the coloured glass be not too dark in colour to be affected by it, precisely the same effect is produced as by a glaze or wash of yellow in oil or water-colour.
Thus we get blue draperies diapered with green, blue-green diapered with yellow-green, and purple with olive, in addition to quite a new development of landscape treatment. A subject was no longer represented on a background of ruby or dense blue, but against a pale grey-blue glass, which stood for sky, and upon it was often a delicately painted landscape, the trees and distant hills stained to green. Stain was no less useful in the foreground. By the use of blue glass stained, instead of pot-metal green, it was easy to sprinkle the green grass with blue flowers, all without lead.
It was by the combination of stain with abrasion that the most elaborately varied effects were produced. The painter could now not only stain his blue glass green (and just so much of it as he wanted green), but he could abrade the blue, so as to get both yellow, where the glass was stained, and white where it was not. Thus on the same piece of glass he could depict among the grass white daisies and yellow buttercups and bluebells blue as nature, he could give even the yellow eye of the daisy and its green calyx; and, by judicious modification of his stain, he could make the leaves of the flowers a different shade of green from the grass about them. The drawing of the flowers and leaves and blades of grass, it need hardly be said, he would get in the usual way, tracing the outline with brown, slightly shading with half tint, and painting out only just enough of the ground to give value to his detail.
In spite of the tediousness of the process, abrasion was now largely used—not only for the purpose of getting here and there a spot of white, as in the eyes of some fiery devil in the representation of the Last Judgment, but extensively in the form of diaper work, oftenest in the forms of dots and spots (the spotted petticoat of the woman taken in adultery in one of the windows at Arezzo seems happily chosen to show that she is a woman of the people), but also very frequently in the form of scroll or arabesque, stained to look like a gold tissue, or even to represent a garment stiff with embroidery and pearls. Often the pattern is in gold-and-white upon ruby or deep golden-brown, or in white-and-gold and green upon blue, and so on. In heraldry it is no uncommon thing to see the ground abraded and the charge left in ruby upon white. Sometimes a small head would be painted upon ruby glass, all of the colour being abraded except just one jewel in a man’s cap.
Stain and abrasion, by means of which either of the three primaries can be got upon white, afford, it will be seen, a workmanlike way of avoiding leadwork. But there are other ways. There is a window at Montmorency in which the stigmata in the hands and foot of S. Francis are represented by spots of ruby glass inlaid or let into the white flesh, with only a ring of lead to hold them in place. It would never have occurred to a fourteenth century glazier to do that. He would have felt bound to connect that ring of lead with the nearest glazing lines, at whatever risk of marring his flesh painting; but then, his painting would not have been so delicate, and would not in any case have suffered so much.
Indeed, the more delicate painting implies a certain avoidance of lead lines crossing it, and hence some very difficult feats of glazing. This kind of inlaying was never very largely used, but on occasion not only a spot but even a ring of glass round it would be let in in this way. There is a window at Bourges in which the glories of the saints are inlaid with jewels of red, blue, green, and violet, which have more the effect of jewellery than if they had been glazed in the usual way. Whether it was worth the pains is another question.
A more usual, and less excusable, way of getting jewels of colour upon white glass was actually to anneal them to it. By abrading the ground it was possible to represent rubies or sapphires, surrounded by pearls, in a setting of gold, but not both rubies and sapphires. In order to get this combination they would cut out little jewels of red and blue, fix them temporarily in their place, and fire the glass until these smaller (and thinner) pieces melted on to and almost into it; the fusion, however, was seldom complete. At this date some of the jewels—as, for example, at S. Michael’s, Spurrier Gate, York—are usually missing—but for which accident one would have been puzzled to know for certain how this effect was produced. The insecurity of this process of annealing is inevitable. Glass is in a perpetual state of contraction and expansion, according to the variation of our changeable climate. The white glass and the coloured cannot be relied upon to contract and expand in equal degree; they are seldom, in fact, truly married. The wedding ring of lead was safer. Sooner or later incompatibility of temper asserts itself, and in the course of time they fidget themselves asunder.
All these contrivances to get rid of leads are evidence that the painter is coming more and more to the front in glass, and that the glazier is retiring more and more into the background. The avoidance of glazing follows, as was said, upon ultra-delicacy of painting, and dependence upon paint follows from the doing away with leads. We have thus not two new systems of work, but two manifestations of one idea—pictorial glass. The pictorial ideal inspired some of the finest glass painting—the windows of William of Marseilles, at Arezzo, to mention only one instance among many. With the early Renaissance glass we arrive at masterly drawing, perfection of painting, and pictorial design, which is yet not incompatible with glass. One may prefer to it, personally, a more downright kind of work; but to deny such work its place, and a very high place, in art is to write oneself down a bigot at the least, if not an ass.
It is not until the painter took to depending upon paint for strength as well as delicacy of effect, trusting to it for the relief of his design, that it is quite safe to say he was on the wrong tack.
Towards the sixteenth century much more pronounced effects of modelling are aimed at, and reached, by the painter. Even in distinctly Gothic work the flesh is strongly painted, but not heavily. In flesh painting, at all events, the necessity of keeping the tone of the glass comparatively light was a safeguard, as yet, against overpainting.