It should always be borne in mind that color was the keynote of this scheme. The custom was practically universal, and enough traces remain to show how splendid was the effect of these old Gothic churches and cathedrals. The priests in their gorgeous vestments, the lights, the crucifix, the banners and incense, the frescoed or diapered walls, and that crowning glory of Gothic art, the stained glass, were all in harmony with these beautiful schemes of colored carved work. Red, blue, green, white and gilding were the tints as a rule used. Not only were the screens painted in colors, but the parts painted white were often further decorated with delicate lines and sprigs of foliage in conventional pattern. The plain surfaces of the panels were also adorned with saints, often on a background of delicate gesso diaper, colored or gilded (Southwold). Nothing could exceed the beauty of the triptychs or retables of Germany, Flanders or France; carved with scenes from the New Testament in high relief arranged under a delicate lacework of canopies and clustered pinnacles glistening with gold and brilliant colors. In Germany the effect was further enhanced by emphasizing parts of the gilding by means of a transparent varnish tinted with red or green, thus giving a special tone to the metallic luster.