[1]

Stained glass is not one of the arts in which the method of production reveals itself at the first glance. Indeed, so few people when looking at a stained-glass window, whether a gorgeous and solemn one of the thirteenth or fourteenth century, or a crude and vulgar one of the nineteenth, realize the long and laborious process by which the result, good or bad, has been obtained. ［23］

[2]

［24］ One hears it so often spoken of as “painted glass” that it is not surprising that there should be a good deal of misconception on the point. It must be clearly understood then that the color effects ［25］ which are the glorious art are not directly produced by painting at all, but by the  ［26］ window building up of a multitude of small pieces of white and colored glass—glass, that is, colored in the making, and of which the artist must choose the exact shades he needs, cut them out to shape, and ［27］ fitting them together to form his design, using a separate piece for every color or shade of color.

[3]

In twelfth and thirteenth century windows many of these pieces are only half an inch wide and from one to two inches long, and few are bigger than the palm of one’s hand; so the reader can ［28］ humor himself, if he wishes, in trying to calculate the number of pieces in one of the huge windows of this date in the Cathedral of Canterbury, York, or Chartres, ［29］ and the labor that has involved this, the initial stage of the process.

[4]

When the window is finished these pieces are put together like a puzzle and joined by grooved strips of lead soldered at the joints, just as any “lattice” window is put together; but before this ［30］ is done the details of the design—features, folds of drapery, patterns, and so on—are painted on the glass in an opaque brownish enamel made of oxide of iron and other metals ground up with a “soft” glass (glass with a low melting-point). This is mixed with oil or gum and water in order to apply it, and then the glass is placed in a kiln and “fired” till the enamel is fused on and, if well fired, becomes part of the glass ［31］ itself, the only “painting” involved in the production of a stained-glass window, and its effect, in the hand of an artist, ［32］ and besides this it enables him to express more than could be done merely with glass and lead, is to decorate and enrich what would otherwise be somewhat crude and papery in effect. ［33］