French polishing became prominent in the 18th century. In the Victorian era, French polishing was commonly used on mahogany and other expensive woods. It was considered the best finish for fine furniture and string instruments such as pianos, lutes and guitars. The process was very labour intensive, and many manufacturers abandoned the technique around 1930
French polishing is a wood finishing technique that results in a very high gloss surface, with a deep colour and chatoyancy. French polishing consists of applying many thin coats of shellac dissolved in alcohol using a rubbing pad lubricated with oil. The rubbing pad is made of absorbent cotton or wool cloth wadding inside a square piece of fabric (usually soft cotton cloth)
“French polish” is a process, not a material. The main material is shellac, although there are several other shellac-based finishes, not all of which class as French polishing.
The finish is considered to be one of the most beautiful ways to finish highly figured wood, but it is also recognised to be fragile. It is softer than modern varnishes and lacquers and is particularly sensitive to spills of water or alcohol, which often produce white cloudy marks. However, it is also simpler to repair than a damaged varnish finish, as patch repairs to French polish may be easily blended into an existing finish.
The process is lengthy and very repetitive. There are also many similar variations in schedule and technique. The finish is obtained through a specific combination of different rubbing motions (generally circles and figure-eights), waiting for considerable time, building up layers of polish and then spiriting off any streaks left in the surface.