Hides and skins are removed from animals after they are slaughtered at modern slaughterhouses. Electric knives and hide pullers that are powered by compressed air are used.

   Fresh fleshed hides are shipped in refrigerated trucks to a tannery for immediate processing into leather. If this is not possible, the fleshed hides are cured, or preserved by immersion for at least 16 hours, in large pools called raceways filled with salty water, or brine. After being cured, the hides can be stored for several months without rotting and can be shipped to manufacturers throughout the world.

   Cured hides arriving at a tannery are rehydrated, or resoaked, and washed in large, rotating wooden drums. Any feathers that might still be on the skin are removed by chemical digestion; that is, by soaking the hide or skin for 10 to 12 hours in drums containing a solution of lime and sodium sulfide and rotating the drums occasionally. After the feathers are removed, hides are delimed, or neutralized, with acids and treated with enzymes to remove any deposits and to increase softness. The next operation is called pickling. The hides are soaked in a solution of water, salt, and hydrochloric or sulfuric acid.

Tanning is the final process in turning hides and skins into finished leather. Properly tanned leather can pass the test of being boiled in water for three minutes without shrinking. There are several methods of tanning, but the two most common are chrome and vegetable tanning. Chrome tanning is the most used. Most leather shoe uppers and garment, upholstery, and bag leathers are chrome-tanned. The process begins in rotating drums with a bath in a chemical containing trivalent chrome. It usually takes eight hours for the chrome to soak all the way into the hide or skin. Once it has penetrated, the chrome is "fixed" by adding to the tanning bath an alkaline chemical such as sodium carbonate or bicarbonate. After this treatment the hide is considered tanned.

   Vegetable tanning is used for such various products as shoe soles, luggage, saddlery, and belt leathers. 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 performed in rotating drums, and it takes from two to four days.

Wringing, splitting, and shaving follow tanning. Wringing lowers themoisture content of the hides in preparation for splitting. Depending on the end use of the leather product, hides are split into sheets of the required thickness and processed further through a shaving machine for added quality. All three operations require specialized machinery run by highly skilled operators.

   After shaving, chrome-tanned hides are again placed in rotating drums with water, dyes, and synthetic tanning materials at temperatures from 120Á to 140Á F (49Á to 60Á C) to obtain the desired color. They are then lubricated with natural fat, synthetic fatty type chemicals, or a combination of both to obtain the softness required by the final product.

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 look at and to touch. Finishing today reflects the latest technology in the use of coating materials. Some finishing processes apply plastics such as acrylic and urethane resins. Others coat with vinyls, waxes, nitrocellulose, dyes, and many other materials. Various mechanical operations are necessary to obtain the desired finish. Hydraulic presses, printing machines, automatic spray applications, and vacuum dryers are a few of the machines used in the finishing process.

   Calfskin has a fine grain. It is good for shoes because it withstands scuffing and hard wear. It is also used for handbags, gloves, fine bookbindings, luggage, and garments.

   Goatskin and kidskin are used in women's fine shoes and gloves. Goatskin is also used in garments. Kid is one of the sturdiest leathers and also one of the softest and most pliable. It is an excellent material for suede, or leather with a napped surface.

   Sheepskin and lambskin are good for shoe uppers and linings, gloves, garments, handbags, chamois, parchments, textile-mill rollers, and piano parts. Lambskins with wool are used for coats and boots.

   Pigskin comes mainly from the peccary, a wild hog found in North and South America, and domestic pigs. When the bristles are removed, pores are left that give it an unusual texture. Pigskin is used for gloves, saddles, wallets, sport shoes, fine bookbindings, upholstery, and razor strops.

   Buckskin is made from deer. Almost all buckskin sold in the United States is imported from Latin America and Canada. It is used for garments, gloves, and the uppers of high-quality shoes.

   Alligator skins, though the animals are carefully protected, are legally available through controlled hunting and farming from Latin America, Florida, and Louisiana. The beautifully textured skins are made into luxurious shoes, handbags, luggage, belts, and billfolds. These accessories are also made from the skins of water snakes, lizards, pythons, and cobras.