History of Leather: From early settlers to modern day people Leather has been used as a durable and flexible material serving countless purposes. Early settlers in America found the native peoples were skilled in the art of leather tanning especially buckskin which is exceptionally soft and water-resistant. The technique was to pile the skins until they began to decay; the decay loosened the hair which was removed by hand along with the flesh from the underside. Oil and animal brains were pounded into the skins, following which they were often smoked. During colonial times, leather enjoyed a range of uses including door hinges, fire buckets, tableware and coach springs. The oak-bark method from thousands of years before was used until the end of the 18th century when people learned that bark from hemlock, chestnut trees and other plant substances could also be used for tanning leather.
Come the end of the 19th century, an American chemist discovered that chromium salts used on hides produced a different kind of raw hide leather, than produced by the traditional bark-tanning method. The new procedure required the resulting leather to be treated with soaps and oils and has become the leading modern method for producing leather. Chrome tanning produced softer more supple leather than vegetable tanning, suitable for the increasing demand for lightweight and fashionable footwear and reflecting our new way of living after the invention of the automobile. The process begins in rotating drums with a bath in a chemical containing trivalent chrome. It usually takes eight hours for the chrome to penetrate all the way into the hide. Once this has been achieved the chrome is “fixed” by adding an alkaline chemical such as sodium carbonate or bicarbonate. After this treatment the hide is considered tanned. Chrome tanning is used in 90% of leather manufacture today. Vegetable tanning is still used in shoe soles, luggage, saddlery, belt leathers and some upholstery. The process is slower than chrome tanning and involves the chemical substance tannin, or tannic acid, which is extracted from the barks of trees. This process is normally performed in drums taking two to four days.
After tanning, wringing lowers the moisture content of the hide in preparation for splitting. Depending on the end use of the leather product, the hides are split into sheets of the required thickness and processed further through a shaving machine for added quality. Around the end of the 19th century, Americans also invented machinery to make the job of leather production easier, including one which could split leather to any desired thickness, thereby increasing output. Machines were also invented that would speed up de-hairing, fleshing and cleaning. After shaving, chrome tanned hides are again placed in rotating drums with hot water, dyes and synthetic tanning materials to obtain the desired color. They are then lubricated with natural fat or synthetic fatty type chemicals, or a combination of both to obtain the softness required by the final product.
The next process is setting, which is the removal of excess water and spreading the hide out prior to drying. Upholstery leather is normally toggle dried (spreading the leather over expanding frames held by “toggles” or clips) hence the clip marks around the entire hide. Staking is the mechanical softening of the leather after drying. The hides may also be softened by milling which is dry tumbling with atomized moisture injected into the tumbler. Finishing consists of placing a series of coatings on the surface of the leather. These coatings are designed to protect the leather and produce surface effects pleasing to the eye and hand. Some finishing processes apply plastics such as acrylic and urethane resins. Others coat with vinyl, wax, nitrocellulose, or dye. Various mechanical operations are necessary to obtain the desired effect. Hydraulic presses, printing, embossing machines, automatic spray applicators and vacuum driers are a few of the machines used in the finishing process. Patent Leather In 1818, Seth Boyden of Newark, New Jersey, invented patent leather after investigating ways to treat leather that would render it dressier than the classic form while retaining its durability. Althouth Seth's process employed a linseed-oil based lacquer coating to give the leather its shiny finish, today patent leather is usually coated in plastic. Patent leather is an eye-catching, water-resistant material reserved for fashion items such as wallets and handbags, shoes, and trench coats.
Dyeing leather holds dye well due to its porous nature. Before the mid-1800s, all dyes were created from vegetable matter. Since then, dyes have been produced using coal-tar or petroleum. Traditionally seen in only black or brown, leather jackets today are dyed in every color imaginable .
Types of leather: Steer hide is pebbly and crinkly in texture and very pliable. It comes in natural or two-toned colors. Cowhide is versatile and natural in color with a smooth grain. Sheep is medium-weight and not as durable as other leathers. Morocco goat is used for linings, billfolds, and book bindings and comes in several colors. Pigskin is durable, comes in a natural color and varies in weight. Suede is a type of finish which is generally made on sheep skins. Suede is available in many colors, and is popular for garments as well as linings.
Leather as a fashion statement . Today, at least half of leather is used in footwear, one-quarter in clothing, only 15% in upholstery, and the remainder in small leather goods. Leather is also used in cars, planes, and equestrian saddles. The leather jacket, used in the military and by aviators (called “bomber jackets”) during World War Two, became a fashion item in the 1950s. After Marlon Brando wore one in The Wild One in 1953, the black leather jacket took on iconic status, representing rebellion and everything “cool”. The leather jacket worn by Fonzie in the Happy Days sitcom became so famous that it now enjoys pride of place at the Smithsonian Institute in Washington. Toward the end of the 20th century, the iconic bomber jacket was joined by the leather coat worn by Arnold Schwarzenegger in the Terminator franchise and Keanu Reeves' leather trench in The Matrix.