In the elaborate tracery of the Decorated or geometric period the mullions, as was said, ask to be pronounced. This was usually done in the Second Gothic period by framing each light with a border, separated from the stonework always by a fillet of white glass. The exception to this was in the case of trefoiled or other many-foiled openings, in which a central medallion or boss, usually circular, extended to the points of the cusps, and the border round the cuspings stopped short against the border to that. Or again in triangular openings a central boss would sometimes extend to its margin, and the borders would stop against that, or pass seemingly behind it.
A typical form of Decorated tracery occurs in the West window at York Minster, by far the most beautiful part of it. There, every important opening has within its white marginal line a broader band of ruby or green, broken at intervals by yellow spots, within which border is foliage of white and yellow on a green or ruby ground. Some of the smaller openings show white and yellow foliage only, without any coloured ground. A plan equally characteristic of the period is illustrated at Tewkesbury. There again occurs similar white foliage, its stem encircling a central spot of yellow. This also is on green and ruby backgrounds, the former reserved for the more prominent openings; but the border is in white, painted with a pattern. This broader white border more effectively relieves the dark lines of the masonry than the border of colour, which sometimes confuses the shapes of the smaller tracery openings: it does so, for example, in the Late glass on [page 200].
186. Part of a Rose Window, German 14th Century.
For what was said of the difficulty of carrying a broad border round the heads of Decorated lights applies more forcibly still to tracery. The merest fillet of colour is often as much as can safely be carried round the opening, if even that. On the other hand, a broad border of white and stain, even though it contain a fair amount of black in it, may safely be used—as at Châlons, where it frames small subjects in rich colour. Some admirable Decorated tracery occurs at Wells, much on the usual lines, and containing a good deal of pleasant green; but there the white and yellow foliage in the centre part of the lights is sometimes so closely designed that very little of the coloured ground shows through it, and it looks at first as if what little ground there is had all been painted-out. At S. Denis Walmgate, York, the background to the foliage in white and yellow (which last predominates) is painted solid: the only pot-metal colour (except in the central medallion head) is in a rosette or two of colour leaded into it; the border is white. Another expedient there employed is to introduce figures in white and stain upon a ground of green or ruby, diapered. At Wells there occur little figures of saints in pot-metal colour, planted upon the white foliated filling of the tracery lights. Decorated circular medallions occupying the centre of ornamental tracery lights are usually framed in coloured lines; occasionally the inner margin of the medallion is cusped, in imitation of stonework.
187. Assisi.
An effective plan, adopted at Evreux, is to gather the lights into groups, by means of the colour introduced into them, which grouping may or may not be indicated by the stonework. In any case, it is a means of obtaining at once variety and breadth of colour.