56. Scratched Diaper.
In draperies, backgrounds, and so on, this is most effectively done in the form of a diaper, often as minute as damascening, which scarcely counts much as pattern. Bold or delicate, a diaper is quite the most effective means of lowering colour; even hard lines seldom appear hard in glass, owing to the spreading of the light as it comes through; but the inevitable hardness of lines scraped out may be mitigated by dabbing the wet paint so as to make it uneven, or by rubbing off part of the paint after the lines have been scraped out. Another and yet another delicate film of paint may be passed over the painted diaper by a skilful hand, but out of each film lights should be scraped if the full value of the glass is to be preserved.
Solid pigment as local colour is a thing to indulge in only with extreme moderation. The strong black lead lines often want lines or touches of black strong enough to keep them in countenance (that is not sufficiently remembered, and it is when it is forgotten that the leads assert their harshness in white glass), and here and there, in work on a small scale, a point of black (a velvet cap, a bag, a shoe, as shown [overleaf],) is very valuable as local colour; but, when the scale allows, it is better always to get this mass in dark-toned glass, which gives the necessary depth of colour most easily, most safely, and with most luminous effect.
The thing not to do, is to paint the robes of black-draped figures in black, a common practice in the seventeenth century. On the other hand, a robe of black richly embroidered with gold and pearls may quite well be rendered, as it was in late Gothic work, by solid paint, because the pearls being only delicately painted, and the gold being in great part perfectly clear yellow stain, plenty of light shines through.
As to the means of getting delicate painting in glass, the utmost delicacy can be got, but it costs patient labour, and there is risk of its going for nothing.
The only quite safe way of getting very delicate effects of painting is to paint much stronger than it is meant to appear. A very fierce fire will then reduce that to a mere ghost of what it was; possibly it will burn it away altogether. Upon this ghost of your first painting you may paint once again, strengthening it (and indeed exaggerating it) in all but quite the most delicate parts. A strong fire will, as before, reduce this without affecting the first painting. Possibly a third or even a fourth painting may be necessary to an effect of high finish. When you have it, it is as lasting as the glass itself.
57. S. Mary’s, Shrewsbury.
This painstaking process, however, is found to be tedious. A much easier plan is to add to the pigment a quantity of borax, or other substance which will make it flow easily in the kiln. That necessitates only a gentle fire, in which there is no risk of burning away the work done, and enables you to do in one or two operations what would have taken three or four. But the gentle fire required to fix soft flux only fixes it gently. Securely to fix the pigment, the glass should have been raised to almost red heat, to the point, in fact, at which it just begins to melt, and the colour actually sinks into it, and becomes one with it. A heat anything like that would have wiped out soft colour altogether. Moreover, the borax flux itself is very readily decomposed by the moisture of a climate like ours. Accordingly the more easily executed work cannot possibly be fast. It fades, they say. That is not the case. It simply crumbles off, sooner or later; but eventually the atmosphere has its way with it. That is how we see in modern windows faces in which the features grow dim and disappear.