5. If the gildings be for outside exposure, as balconies, gratings, statues, &c., they must not be varnished, as simple oil gilding stands better; for when it is varnished, a bright sun-beam acting after heavy rain, gives the gilding a jagged appearance. When the objects are inside ones, a coat of spirit varnish may be passed over the gold leaf, then a glow from the gilder’s chafing dish may be given, and finally a coat of oil varnish. The workman who causes the chafing dish to glide in front of the varnished surface, must avoid stopping for an instant opposite any point, otherwise he would cause the varnish to boil and blister. This heat brings out the whole transparency of the varnish, and lustre of the gold.
Oil Gilding is employed with varnish polish, upon equipages, mirror-frames, and other furniture. The following method is employed by eminent gilders at Paris.
1. White lead, with half its weight of yellow ochre, and a little litharge, are separately ground very fine; and the whole is then tempered with linseed oil, thinned with essence of turpentine, and applied in an evenly coat, called impression.
2. When this coat is quite dry, several coats of the hard tint are given, even so many as 10 or 12, should the surface require it for smoothing and filling up the pores. These coats are given daily, leaving them to dry in the interval in a warm sunny exposure.
3. When the work is perfectly dry, it is first softened down with pumice stone and water, afterwards with worsted cloth and very finely powdered pumice, till the hard tint give no reflection, and be smooth as glass.
4. With a camel’s hair brush, there must be given lightly and with a gentle heat, from 4 to 5 coats at least, and even sometimes double that number, of fine lac varnish.
5. When these are dry, the grounds of the pannels and the sculptures must be first polished with shave-grass (de la prèle); and next with putty of tin and tripoli, tempered with water, applied with woollen cloth; by which the varnish is polished till it shines like a mirror.
6. The work thus polished is carried into a hot place, free from dust, where it receives very lightly and smoothly, a thin coat of gold colour, much softened down. This coat is passed over it with a clean soft brush, and the thinner it is the better.
7. Whenever the gold colour is dry enough to take the gold, which is known by laying the back of the hand on a corner of the frame work, the gilding is begun and finished as usual.
8. The gold is smoothed off with a very soft brush, one of camel’s hair for example, of three fingers’ breadth; after which it is left to dry for several days.