Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/175

Rh gold and between the two coats of gold, the better polish can be obtained.

In all other methods of gilding the gold is attached from the back of the leaf, and the finished work shows the unalloyed brightness of the metal, but in the case of glass gilding, the size comes between the gold and the eye, and the glass interposes a further medium, so that it is at once apparent that the cleaner the glass, and the clearer and thinner the film of size, the less is the brilliance of the gilding interfered with. The purity and cleanliness of the size and glass will be assured if the size can be laid upon the glass without cissing or gathering. If it runs off like water on a duck's back, the glass is greasy or the size is not clean, or perhaps the water used is too hard, boiled rain water makes the best size, but it must be clean and clear.

Gilding on glass requires a second coat in order to make a solid job. The first coat of gold when dry is lightly polished with finest cotton wool, and fixed and burnished by scalding with very hot water as near boiling as can be used without splitting the glass. It may be poured over from the spout of a kettle, so as to run over the whole of the gilding, and then down on to the ground, or laid over with a broad 4-inch camel-hair flat. This removes the scum of the size from between the gilding and the glass and adds to its clarity and brilliance. The work may then be carefully polished with a piece of finest cotton wool. It is then allowed to dry and the whole of the gilding and clearing with hot water repeated. After this the gold is backed up by a coat of hard Japan or varnish which will dry in about eight hours and have a perfect gloss. In cold weather the whole of the glass must be treated with the hot water whether gilded or not, or breakage will result from the inequality of expansion produced, and if the day be frosty, the job must be done very cautiously in a hot shop, or defended. The water must never be boiling.

The gold used for glass gilding is specially prepared, being