Borders.—All windows have, as a rule, borders; but they are narrower than in Early work.
Tracery lights, which now form a conspicuous part of the window, are, as a rule, also each separately bordered, often with a still narrower border in colour, or it may be only a line of colour.
Grisaille windows have usually coloured borders, foliaged or heraldic (as [above]). The border does not necessarily frame the light at its base; very often there is an inscription there. Between the coloured border and the stonework is still invariably a marginal line of white glass.
Sometimes, more especially in tracery, this white line is broad enough to have a pattern painted upon it, in which case there is no coloured border. Or this white border line may be enriched at intervals by rosettes or blocks of colour upon it. Or, again, it may be in part tinted with pale yellow stain.
Some such border is usually carried round each separate tracery light, with the result that Decorated tracery may usually be distinguished at a glance from later work by a certain lack of breadth about it.
There is no need to say more about Decorated tracery, seeing that the idea of this epitome is to enable the amateur to form some opinion as to the period of a window, and not to prompt the designer. The geometric character of the stonework proclaims the period, and, unless there is something in the design of the glass to indicate a later date, it may be taken to belong to it. It cannot well be earlier if it fits.
229. S. Ouen, Rouen.
Stain.—Yellow stain is proof positive that the glass is not much earlier than the fourteenth century, for it is only about that time that the process of staining white glass yellow was discovered. The occurrence therefore of white and colour upon the same piece of glass—i.e., not glazed up with it, but stained upon it, is indicative of Middle or Late Gothic.