Blue dye was called indigo because it came from the roots of a plant called Indigofera tinctoria (in-de-GO-fer-uh tinc-TOH-ree-uh), meaning "dye from India." It ranged from dark blue to grayish purple-blue.
Scarlet dye was obtained from various tropical insects: the dried bodies of the female Kermes ilicis (CUR-meez ILL-i-sis), or the dried female Coccus cacti (KAH-kuss KAK-tee), which feeds on prickly pear cactus in Mexico and Central America. The one was called kermes (CUR-meez), the other, cochineal (KAH-chuh-neel). Both produced a strong to vivid red or reddish orange. Lewis and Clark might have discovered an unexpected commercial resource on the High Plains, had they been able to recognize the fluffy white cochineal tents on some of the prickly-pear cactus stems whose spines punctured their moccasins.
The dye called "Turkey red" was preferred by both the British and French — and possibly American — armies at the end of the 18th century. It was produced by treatingthe crystaline compound alizarin (a-LIZ-er-in), from the root of the madder plant, with aluminum hydroxide, shifting the hue from orange red to medium red.
Black dye of various qualities came from several sources, but the best was from the heart of a spiny tropical American tree called logwood. Americans also used black walnuts to make a dark brown or black stain, particularly for use on leather.
Incidentally, the shellac used to add rigidity to the beaver hats the men wore was made from lac, the resinous incrustation formed on twigs and branches of trees by the female of an East Indian insect, Laccifer lacca, (LAH-si-fer LAH-ka) which is related to the cochineal insect.
Until synthetic dyes were introduced in the 1850s, and shellacs in the 20th century, all those commodities had to be imported. Thus President Jefferson's embargo on certain foreign trade in1807 resulted in a shortage of blue dye during the War of 1812, and U.S. soldiers were then dressed in gray instead of blue. The beaver hat went out of style beginning in the 1830s, when increased trade with the Orient made silk hats less expensive and lighter in weight than beaver felt.
Edited by Robert J. Moore, Jr.