The practice of painting on glass, i.e. of ap plying color with the brush on fusible pigments fixed by heat, began in the use of grisaille, a browning pigment, for eross-hatching and outlin ing on clear glass the ornamental details of the backgrounds, in order to soften the glare of the dear glass without introducing disturbing color elements. It was then applied, even in early French windows, to the faces and hands to indi cate the features and fingers; and its use ex tended gradually to all the shaded details, the inscriptions and ornaments, of the later window's. The perfection of the French work of the thir teenth century has never been equaled. These series of cathedral windows were also one of the principal branches of Christian iconography (q.v.), joining with sculpture in expressing the subjects of religious thought in art..
During the latter part of the thirteenth cen tury the art was carried to England, Germany, and Italy, where it did not really flourish before the following century. In Italy the 'imperfect understanding of Gothic methods did not allow of the use of such immense windows, and the art never became thoroughly acclimated. At Arezzo Cathedral are some windows by a French artist, Guillaume de Mareillati„ proving the transmis sion from France. Other interesting examples are in San Francesco at Assisi. San Petronio in Bologna, and the Cathedral and Santa Croce in Florence. Many of the best Italian examples be long rather to the early Renaissance than to the late Gothic. England would have possessed some very fine series, as is shown by the examples at York and Canterbury, had it not been for the vandalism of the Reformation. In Spain there are fine windows at Toledo and Leon, very close to French models. Germany, however, ranks next to France in the importance of its remain ing windows, beginning in the fourteenth cen tury, with those of the choir of Cologne Cathe dral, those of the cathedrals of Freiburg, Strass burg, and Regensburg, and the at Op penheim, Esslingen, and Nuremberg. German works, however, do not approach the French in quality either of technique or art.
As the fifteenth century approached the use of yrisaille or light colorless monochrome windows increased. This process had always been in use for smaller windows or borders with geometric designs, as at Obasine and Auzerre in France, Heiligenkrenz in Austria, and Sainte Gudule at Brussels, but it became more popular and was used in larger windows as the Renaissance period approached; the brown enamel on the white o• greenish ground became lighter, all the glass less opaque, and the leads more delicate. In colored glass windows a brilliant window became very popular, while green and violet went out of fashion. The donor's window at the Cathedral of Evrenx shows how the fourteenth-eentury artist substituted realism for the older conventions, and introduced profusely architectural forms as framework and background of the figures. The increased use of the white line and background and the invention of the yellow stain, used pro fusely in place of the applied enamel, increased the light effect. With the approach of the fif teenth century the increased perfection in draw ing and naturalism does not compensate for the loss of the special methods of glass painting, for which artists commenced to substitute effects taken from wall and other forms of opaque painting. In Germany a peculiar novelty popular during the Renaissance was the use of coats of arms as the exclusive or almost exclusive design.
The extreme of possible realism was then reached in the architectural and landscape effects of the windows at Gouda in Holland. Jean Cousin in France; Holbein, Ghiberti, and Paolo Uccello in Italy; Dtirer and Baldung OHM in Germany— were among the prominent artists of the Renais sance who designed windows. At the same time this very fall of the glass-painter to the rank of an artisan and the influence of painting on his art hastened its fall in the seventeenth century.
The attempts to revive it during the two fol lowing centuries, as exemplified by Sir Joshua Reynolds's remarks, were based upon the same mistaken principles. The glass windows pro duced to the middle of the nineteenth century were paintings on glass in imitation of oil or water-eolo• pictures—of opaque effects in paint ing. The majority are, therefore, inadequate and commonplace, works of industry rather than art. The Munich School bettered the process some what; the revival of the study of Gothie art be tween 1S50 and 1875, especially that initiated in France by Viollet-le-Duc, led to a better appre ciation of and an attempt to revert to mediawal processes. The French first rediscovered them, and American artists, of whom the most promi nent is John La Fargo, have done perhaps more than any others during the last decade to replace glass painting again in the sphere of real art. Besides studying again the irradiation of colors, the special requirements of transparent painting, and the consequent grouping of complementary colors, artists like La Farge and Tiffany have pro duced wonderful effects in iridescence with an in crease of richness in tones similar to glass mosaic wo•k. A questionable but extremely popular American innovation has been the introduction of what may be called modeled glass, to repro duce the effects of shading by its purposed or ac cidental variations of thickness. American artists also make large use of the accidental streakings of vari-colored glass ('pot metal') to produce pictorial effects without painting and without too minute subdivision and leading of the picture.
BIBLIOGRAPHY. Levy, Histoire de la peinture Bibliography. Levy, Histoire de la peinture stir verre en Europe (Brussels, 1854-60) ; Gers pach, L'art de la rerecrie (Paris, 1885) ; West lake, History of Design in Painted Glass (Ox ford, 1879-94) ; Kolb, Glasmalernien des Mittel alters mid der Renaissance, with 60 plates (Stutt gart, 1884-89) ; Didron, in Annales arekeolo gigues, vols. xxiii., xsiv., xxvii. (Paris, 1878-81). The first historic study, really scientific and ar tistic, was Viollet-le-Duc's article "Vitraux" in his great Diationnairc raisonne de l'areltiteeture f rano ise (Paris, 1353-68). Consult also:. Las teyrie, Histoire de la peinture stir verre d'apres ses monuments cn France, with 110 plates (ib., 1853-57). and Geyling and Lbw, illeisterwcrke der kirchliehen Glasmalerci (Vienna, 1595 et seq.). A model publication of one of the great series of Gothic windows is Hucher, Vitraux peints de la cathedrals du, Mans (Le Mans, 1864), with 100 immense plates. For American work con sult Sturgis, "Decorative Windows in England and America." in Architectural Record, vol. vi. (New York, 1896-97) ; La Farge, The American Art of Glass (New York, 1893), and the same author's article "Window" in Sturgis, Dictionary of Architecture (New York, 1901).