Ebonising is a process for darkening wood, giving it an appearance similar to

ebony Ebony is a dense black/brown hardwood, coming from several species in the genus '' Diospyros'', which also contains the persimmons. Unlike most woods, ebony is dense enough to sink in water. It is finely textured and has a mirror finish when ...

, hence the name. It is particularly used for

piano The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keybo ...

s and fine furniture.

History

While little record exists of who invented ebonizing, it was popular among the upper classes throughout the Early Modern period, especially when ebony was scarce. In the 19th century, ebonizing became popular as ebony was no longer nearly plentiful enough to feed demand for the new mass market furniture.

Processes

One process uses

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

dissolved in

vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to eth ...

as the darkening agent. The

ferric acetate Ferric acetate is the acetate salt of the coordination complex e3O(OAc)6(H2O)3sup>+ (OAc− is CH3CO2−). Commonly the salt is known as "basic iron acetate". The formation of the red-brown complex was once used as a test for ferric ions. Stru ...

thus formed reacts with the

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

in the wood, forming a black substance crusting the top of the wood. Since hardwoods have higher tannin content, they are more convenient woods to ebonize. However, softwoods can be ebonized by soaking them with tea (which has a high tannin content) and then applying the solution.

References

{{furniture-stub Furniture-making