1565. There is another design, printed in imitation of the half-light (abat-jour); this is used principally for a ground, covering the whole surface of the glass, within which (the necessary spaces having been previously cut out before it is stuck on the glass), are placed medallion centres of Watteau figures, perfectly transparent, which derive increased brilliancy from the semi-transparency of the surrounding ground.
1566. To ascertain the quantity of designs required, measure your glass carefully, and then calculate how many sheets it will take. The sheets are arranged so that they can be joined together continuously, or cut to any size or shape.
1567. Practical Instructions.—Choose a fine day for the operation, as the glass should be perfectly dry and unaffected by the humidity of the atmosphere.
1568. Of course, if you have a choice, it is more convenient to work on your glass before it is fixed in the frame. If you are working on a piece of unattached glass, lay it on a flat table (a marble slab is preferable), over which you must previously lay a piece of baize or cloth to keep the glass steady.
1569. The glass being thus fixed, clean and polish the side on which you intend to operate (in windows this is the inner side), then with your brush lay on it very equably a good coat of the prepared varnish; let this dry for an hour, more or less, according to the dryness of the atmosphere and the thickness of the coat of varnish.