Tanning (leather) in the context of "Acid"

Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hogs, ostriches, and aquatic animals such as seals and alligators.

Leather can be used to make a variety of items, including clothing, footwear, handbags, furniture, tools and sports equipment, and lasts for decades. Leather making has been practiced for more than 7,000 years and the leading producers of leather today are China and India.

Parchment is a writing material made from specially prepared untanned skins of animals—primarily sheep, calves and goats. It has been used as a writing medium in West Asia and Europe for more than two millennia. By 400 AD many of the written works intended for preservation in these regions had been transferred from papyrus to parchment. Vellum is a type of fine-quality parchment made from the skins of young animals such as lambs and young calves.The generic term animal membrane is sometimes used by libraries and museums that wish to avoid distinguishing between parchment and vellum.

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 is widely applied to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups (such as carboxyls) to form strong complexes with various macromolecules.

The term tannin (from scientific French tannin, from French tan "crushed oak bark", tanner "to tan", cognate with English tanning, Medieval Latin tannare, from Proto-Celtic *tannos "oak") refers to the abundance of these compounds in oak bark, which was used in tanning animal hides into leather.

Buckskin is the soft, pliable, porous preserved hide of an animal – usually deer – tanned in the same way as deerskin clothing worn by Native Americans. Some leather sold as "buckskin" may now be sheepskin tanned with modern chromate tanning chemicals and dyed to resemble real buckskin.

Traditionally, Native Americans would scrape away the excessive fat clinging to the hide, and this would be followed by working the raw hide with the brain tissue of an animal. Afterwards, the raw hide is made to envelope a fire that emits wood smoke, and where the smoke is mostly trapped inside the raw hide for many hours. The combined application of brain tissue and smoke produces soft and pliable buckskin leather, with a dark honey color. This treatment differs from the traditional tanning methods used in other societies and cultures and is thought to be preferable to vegetable tanning methods where tannins are exclusively used. The finished product resembles chamois leather, but is stronger. Smoking gives to the leather its durability, and although buckskin may become slightly stiff when it dries after being wet, it quickly restores itself to its former soft-state by rubbing it with the hands. The application of wood smoke also deters insects from devouring it. Unsmoked buckskin is lighter, even white, in color.

A bog body is a human cadaver that has been naturally mummified in a peat bog. Such bodies, sometimes known as bog people, are both geographically and chronologically widespread, having been dated between 8000 BC and the Second World War. The common factors of bog bodies are that they have been found in peat and are at least partially preserved. However, the actual levels of preservation vary widely, from immaculately preserved to mere skeletons.

Due to the unusual conditions of peat bogs – highly acidic water, low temperature, and a lack of oxygen – the soft tissue of bog bodies can be remarkably well-preserved in comparison to typical ancient human remains. The high levels of acidity can tan their skin and preserve internal organs, but inversely dissolve the calcium phosphate of bone. The natural protein keratin, present in skin, hair, nails, wool and leather, is resistant to the acidic conditions of peat bogs.

Tanbark is the bark of certain species of trees, traditionally used for tanning hides into leather.

The words "tannin", "tanning", "tan," and "tawny" are derived from the Medieval Latin tannare, "to convert into leather."

Goatskin refers to the skin of a goat, which by long term usage, is denoted by the term Morocco leather. Kidskin, used for gloves, shoes and other accessories, is traditionally goatskin, although other leathers such as sheep and kangaroo can be used to make kid.

Tanned leather from goatskin is considered extremely durable and is commonly used to make rugs (for example in Indonesia) and carpet binding. It is often used for gloves, boots, and other products that require a soft hide. Kid gloves, popular in Victorian times, are still made today. It has been a major material for leather bookbindings for centuries, and the oldest European binding, that of the St Cuthbert Gospel in the British Library, is in red goatskin. Goatskin is used for a traditional Spanish container for wine bota bag (or called goatskin). Traditional kefir was made in bags from goatskin.

Skinning is the act of skin removal. The process is done by humans to animals, mainly as a means to prepare the meat beneath for cooking and consumption, or to harvest the skin for making fur clothing or tanning it to make leather. The skin may also be used as a trophy or taxidermy, sold on the fur market, or, in the case of a declared pest, used as proof of kill to obtain a bounty from a government health, agricultural, or game agency.

Two common methods of skinning are open skinning and case skinning. Typically, large animals are open skinned and smaller animals are case skinned.