Windows: A Book About Stained & Painted Glass

by Lewis F. Day

A first consideration in the design of a window are the bars which are to support it. The skilled designer begins by setting these out upon his paper, nearer or closer together, according to the width of the opening, from nine to eighteen inches asunder. In a wide window it may be as well to make every second or third bar extra strong. Upright stanchions may also be introduced. Exigencies of design may make it necessary to alter the arrangement of bars with which you set out. You may have occasionally to bend one of them to escape a face, or other important feature; but, if you begin with them, this will not often be necessary. Bars may be shaped to follow the lines of the design. There is nothing against that, except that it is rather costly to do; and, on the whole, it is hardly worth doing. In big windows, such as those at King’s College, Cambridge, raised some feet above the level of the eye, stout bars have, in effect, only about the value of strong lead lines, whilst lead lines disappear.

The points to be observed with regard to glazing are these: Since leads must form lines, it is as well to throw them as much as possible into outlines. In a cleverly glazed window the design will tell even when the paint has perished. To glaze a picture in squares, regardless of the drawing, is mere brutality. Because by aid of the diamond glass may actually be cut to almost any shape, it is not advisable, therefore, to design shapes awkward to cut, but rather to design the lead lines of a window with a view to simplicity of cutting and strength of glazing. Pieces of glass difficult to cut are the first to break. It is the business of the designer to anticipate breakage by introducing a lead just where it would occur. Tours de force in glazing are not worth doing. It is a mistake to be afraid of leads. Skilfully introduced, they help the effect; and, except in work which comes very near the eye, they are lost in the glass.

The quality of pot-metal glass is all important. It should never be mechanically flat and even. The mechanically imperfect material made in the Middle Ages is so infinitely superior to the perfect manufacture of our day, that we have had deliberately to aim at the accidents of colour and surface which followed naturally from the ruder appliances and less accurate science of those days. There are legends about lost secrets of glass making, to which much modern produce gives an appearance of truth. But, as a matter of fact, though old glass undoubtedly owes something of its charm to weathering, better and more beautiful glass was never made than is now produced; but it is not of the cheapest, and it wants choosing.

The choice of glass is a very serious matter. What are called “spoilt” sheets are invaluable. It takes an artist to pick the pieces. But without experience in glass the judgment even of a colourist will often be at fault. Some colours spread unduly, so that the effect of the juxtaposition of any two is not by any means the same as it would be in painting. It is only by practical experiment that a man learns, for example, how much red will, in conjunction with blue, run into purple, and which shade of either colour best holds its own. Effects of this kind have been more or less scientifically explained—by M. Viollet le Duc for one—but, in order to profit by any such explanation, a man must have experience also.

Referring to “flashed” glass, all kinds of double-glass are now made: red and blue = purple, yellow and blue = green, and so on; but there is not, except, perhaps, in work on quite a small scale, much to be gained by this. In fact, it is not well in work on a fairly large scale to depend too much upon etching pattern out of coated glass. In a window breadth of effect is of more account than minuteness of detail. Damask or other patterns in draperies might, more often than they are, be leaded up in pot-metal. It would compel simplicity on the part of the designer, and the effect of the glass would be richer.

With the increasing variety of coloured glass now made, plating becomes less necessary than once it was. The drawback to the practice is that dust and dirt may insinuate themselves between the two pieces of glass, and deaden the colour. The safe plan is to fuse the two pieces of glass together.

Good glass is more than half the battle. Raw glass may be toned down by paint, but poor glass cannot be made rich by it. The Italian glass painters often used crude greens and purples, and softened them with brown. They might do that with comparative safety under an Italian sky; but the deeper tones produced that way have not the purity and lusciousness of juicy pot-metal, and the paint is liable to peel off and betray the poverty of the cheap material. It is the fundamental mistake of the painter, because by means of paint he can do so much, to depend upon it for more than it can do. The toning of local colour with brown paint is only a makeshift for more thoroughly mosaic work; but it is an ever-present temptation to the painter, and one against which he should be on his guard.

The actual technique of glass painting, it has been explained already, is quite different from painting as the painter understands it; often it is not so much painting as scraping out paint. The artist may, nay must, choose his own technique. He will get his effect in the way most sympathetic to him. What he has to remember is, that, except where he wants actually to stop out light, he must get light into his shadows—whether by stippling the wet colour, or by scrubbing it when dry with a hog tool, or by scraping with a point, is his affair. For example, if he wants to lower the tint of a piece of glass, the worst thing he could do would be to coat it with an even film of paint. It would be better to stipple it so that in parts more light came through. But the best way of preserving the brilliancy of the glass would be either to paint the glass with cross-hatched lines, or to scrape bright lines out of a coat of paint.