Depth and shine in the grain of the wood
French polishing is a form of polishing in which shellac is used. It requires a certain skill in the technique and a great deal of time and patience. It is used for finishing veneered furniture, furniture on which “lastronatura” has been applied (a technique very similar to veneering but usually with slightly thicker slices of wood) or in any case of fine workmanship, bestowing the furniture with unparalleled shine and depth.
Shellac is an organic resin secreted by an insect cochineal family, a parasite of varieties of plants of the Indian subcontinent. It is prepared by dissolving the scales shellac in a solution of ethyl alcohol, then leaving the mixture to rest for 24 hours and finally, filtering it to eliminate the impurities.
The phases of the process
Pumicing. The aim of this is to block the pores of the wood to make the surface smoother. The pumice powder is “dusted” over the surface and then rubbed vigorously with a wad to make it penetrate the pores and close them.
Polishing. This is performed by spreading the shellac on the wood using a fresh wad: as the alcohol contained in the solution evaporates, it leaves only a very fine layer of shellac, which becomes hard on contact with the air, thus emphasising the grain and colour of the wood. This step is repeated many times, with the trick of letting the surface dry between one coat and the next.
Buffing. This is the final step, which is more delicate and difficult, but of fundamental importance because it will bring the wood to its final shine. The aim is to eliminate the signs of the wad and the imperfections of the varnish. For the buffing phase, a new wad is made with very fine fabric and is moistened with a highly diluted concentration of shellac.