Polychromy was one of the decorative inventions of the Louis XV style.
In order to introduce color into furniture, polychrome craftsmen had the choice of several formulas. They began by spreading one or two coats of white. After polishing these coats, they applied coats of color that were heated. To obtain a perfect result, they began with two coats of rather strong glue, cold-ground and of equal thickness everywhere. Then, when the whole was completely dry, they applied colorless varnish. Lastly, they added the coats of color.
Another procedure, although more complicated, produced excellent results: it was called “chipolin.” It consisted in applying seven or eight coats of white primer, freeing and smoothing the moldings or ornaments and lastly adding two coats of the desired color. The final step was a coat or two of pure light cold glue and two coats of alcohol varnish.
It is often difficult nowadays to recreate the shades used in the XVIIIth century:
- green was obtained with ceruse (white lead) and forest green ground and diluted with glue.
- ordinary green, with a pound of ceruse, 60 grams of Troyes yellow lake and 15 grams of Prussian blue.
- jonquil yellow with ceruse and Troyes yellow lake.
- lemon yellow, with red and yellow orpiment.
- pearl gray, with ceruse, vine black and a touch of pearl blue.
- lilac, with one part azurite mixed with two parts pink lake and one part pure white.
- violet, with lake, ceruse and a little carmine. (Ceruse, basic lead carbonate, is a poison. Its use has been prohibited since 1915).