Windows: A Book About Stained & Painted Glass

by Lewis F. Day

The scale of execution would determine whether each or any province could be cut out of a single sheet of glass, but the lines of latitude and longitude would give an opportunity of using often three or four pieces of glass to a province without introducing lines which formed no part of the design. That, however, would be contrary to early usage, which was never to make use of the leads as independent lines, but only as boundaries between two colours. There is a reason for this reticence. You will see that in the surface of the sea, where the latitudinal and longitudinal lines come in most usefully, it is necessary to use also other leads, which mean nothing but that a joint is there desirable. These constructional leads, when they merely break up a background, are quite unobjectionable—they even give an opportunity of getting variety in the colour of the ground—but when some of the leads are meant to assert themselves as drawing lines and some are not, the result is inevitably confused.

2. THE WAY A WINDOW IS GLAZED.

All that the glass gives us in our mosaic map is the local colour of sea and land—the sea, let us say, dark blue, the countries, provinces, and islands each of its own distinctive tint. When it comes to giving their names, it would be possible indeed on a very large scale to cut the letters out of glass of darker colour, and glaze them in as shown in the title word “Italy.” That would involve, as will be seen, a network of connecting lead lines. On a much smaller scale there would be nothing for it but to have recourse to the supplementary process, and paint them. The words Germany, Austria, Turkey, Naples, Sicily, and the rest would have to be simply painted in opaque colour upon the translucent glass.

But, once we have begun to use paint, there are intermediate ways between these two methods of inscription, either of which would be adopted according to the scale of the lettering. These are shown in the names of the seas. In the word “Mediterranean” each separate letter would be cut out of a piece of glass, corresponding as nearly as possible to its general outline or circumference, and its shape would be made perfect by “painting out”—that is to say, by obscuring with solid pigment that part of the glass (indicated by dots in the drawing) which was meant to retire into the background. Presuming this wording to be in a light colour and the background darkish, this amount of painting would, as a matter of fact, be quite lost in the dark colour. In the lesser descriptions “Tyrrhenian” and “Adriatic Sea,” each separate word, instead of each letter, would be cut out of one piece of glass (or perhaps two in the longer words), and the background would be painted out as already described.

Paint would further be used to indicate the rivers, the mountains, the towns, or any other detail it was necessary to give, as well as to mark such indentations in the coastline as were too minute to be followed by the thick lead. As a matter of practice, it is usual to paint a marginal line of opaque colour round the glass representing just a little more than that portion eventually to be covered by the flange of the lead, so as to make sure that that will not by any chance cut off from view what may be an important feature in the design.

For example, the mere projection of a lead which too nearly approached the delicate profile of a small face might easily destroy its outline. The glazier’s lead, it should be explained, is a wire of about a quarter of an inch diameter, deeply grooved on two sides for the insertion of the glass. Imagine the surfaces exposed to view on each face of the window to be flattened, and you have a section very much like the letter H, the uprights representing the flanges, and the cross-bar the “core,” which holds them together and supports the glass mosaic.

The process of painting employed so far is of the simplest; it consists merely in obscuring the glass with solid paint. This is laid on with a long-haired pencil or “tracing brush.” The paint itself may be mixed with oil or gum and water, or any medium which will temporarily attach it to the glass and disappear in the kiln; for the real fixing of the paint is done solely by the action of the fire. The pigment employed consists, that is to say, of per-oxides of iron and manganese ground up with a sufficient amount of powdered flint-glass or some equivalent silicate, which by the action of the fire is fused with the glass (reduced to very nearly red heat), and becomes practically part and parcel of it.

Whenever a glass painter speaks of painted glass that is what he means—viz., that the colour is thus indelibly burnt in. After the middle of the sixteenth century various metallic oxides were used to produce various more or less transparent pigments (enamel colours as they are called to distinguish them from the pot-metal colours), but in the thirteenth century transparent enamel colours were as yet unknown to the glass painter, and he confined himself to the solid deep brown pigment already spoken of—an enamel also, strictly speaking, but by no means to be confounded with the enamel colours of later centuries. Those were colours used for colour’s sake; this is simply an opaque substance used solely on account of its capacity to stop out so much of the colour of pot-metal glass as may be necessary in order to define form and give the drawing of detail; and in effect the brown, when seen against the light, does not tell as colour at all but merely as so much blackness. The only colour in the window is the colour of the various component pieces of glass. Thus in the case of an early figure ([page 33]) the face would be cut out of a sheet of pinkish glass and the features painted upon it in brown lines; each garment would be cut out of the tint it was meant to be, and the folds of the drapery outlined upon the pot-metal. In like manner a tree would be cut out of green glass, its stem perhaps out of brown, and only the forms of the leaves, and their veining, if any, would be traced in paint. In the execution of the map there is no occasion for further painting than this simplest and fittest kind of work, little more than the glazier would himself have done had his means allowed him. And in the very earliest glass the painter was almost as sparing of paint as this: he did, however—it was inevitable that he should—use lines, whether in drawing the features of a face or the folds of drapery, which were not quite solid, and which consequently only deepened the colour of the pot-metal, and did not quite obscure it: he went so far even as to pass a smear of still thinner colour, a half tint or less, over portions of the glass which he wished to lower in tone. He began, in fact, however tentatively, to introduce shading. Happily he was careful always to use it only as a softening influence in his design, and never to sacrifice to it anything of the intrinsic beauty and brilliancy of his glass.