Leather is the tanned skin, or rawhide, of an animal. There are various processes for tanning hides and turning them into leather.

Rawhides are produced by removing the flesh, fat and hair from skins. This is usually done by soaking the skins in urine or lime and water or wood ash and water, and then scraping the skins. Rawhides are soaked in water for several hours or days before tanning.

Hides used to be tanned by being pounded with animal dung or soaked in animal brains. Brain tanned leather is very soft and can be washed. Brained leather may be smoked so as to prevent it rotting.

If there is to be a significant time lag between skinning an animal and treating its skin, the skin can be cured with salt. If this is done, the salt is later removed by soaking the skin in water.

The process of removing hair from hides is known as scudding.

Tanning is the treating of a dead animal's skin with tannins. Tannins are forms of gallic acid that come either from gall (produced by the gall bladders of animals), or from tree bark or wood or other plant tissue, or from mineral solutions.

If mineral tanning is to be done, the hide is pickled in a mixture of salt and sulfuric acid.

Tanning alters the protein structure of the skins, making them a different texture to the original skin, more flexible, and far less prone to decay.

Vegetable tanning

Leather produced by treating skin with vegetable tannins is affected by water, and if soaked it may discolor and/or shrink and/or become hard when it dries. This quality can, however, be used to advantage. For example, in the past, vegetable tanned leather could be boiled and shaped and made to go hard so that it could then be used as armor.

In vegetable tanning, skins are stretched on frames and soaked for several weeks in tannic solutions, being moved up from lower concentration solutions to higher concentration solutions.

Chrome Tanning

This process was invented in 1858. Skins are tanned using chrome sulfate and other chromium salts. The resulting leather discolors, hardens and loses its shape less than vegetable tanned leather does.

After a skin has been chrome tanned, it is a bluish color and is referred to as 'wet blue'.

The advantage of chrome tanning is that it can be done in a day. It produces a stretchable leather.

Aldehyde Tanning

This is done using glutaraldehyde or oxazolidine compounds. The resulting leather tends to be white or pale cream color, and so is referred to as 'wet white'.

Formaldehyde tanning is a type of aldehyde tanning, but it is being phased out on the grounds of being harmful to the health of workers who use it.

Chamois - from the goat-antelope of that name - is aldehyde tanned and is used in traditional car washing because it absorbs water very well.

There is a leather produced by tanning skin with attar of roses.

Synthetic tanned leather is produced with polymers such as melamine. The leather comes out white.

An alternative to tanning is tawing, which is done with alum, aluminum salts and other salts. The skin is soaked in a solution of these salts. The resulting leather tends to be softer and more pliable and stretchable than tanned leather.

Various Types Of Leather

Leather can be finished in several ways. It can be waxed or oiled. It can be split (i.e. produce two or three times the original area of leather). The surface can be shaved. Of course leathers can be dyed. And it can be turned into suede by abrading the surface with a rough roller. It can be buffed, which is to take the inner leather from a three-way split or to take the flesh side of a two-way split and color and texture it so that the non-outer surface has the appearance of the outer surface leather. Emery wheels are used on the flesh side of leathers, and carborundum paper is used on the skin side. Snuffing is buffing done lightly. Leather that is so lightly snuffed as not to have its grain impaired is said to be 'corrected grain'.

Leathers can be …

Full Grain

These are leathers where the surface has not been sanded, buffed, snuffed. Full grains can be aniline dyed (soluble dye that soaks in and leaves the surface texture unaltered) or semi-aniline that does the same but then the surface is treated in some way.

Top Grain

This has had the underside split away to give an extra saleable piece of leather. Because it's thinner it is more flexible than full grain (which is unsplit). The surface is sanded and has a finishing coat added.

Corrected Grain

This has an artificial leather grain appearance added to its surface. This treatment is done to imperfect skins that are sanded off and then impressed with a grain appearance. Solid pigment may then be used to further conceal blemishes. (Soluble dyes that leave the real skin texture revealed are used for good quality skins.)


This is where leathers are split so that the top (skin) side can be used, and lower layers can be split away from it for correcting or some other use,

Splits are used to make suede, the best being that where just the grain (skin side) layer has been removed. Otherwise a flesh-side split can be used with the flesh side being shaved and rough-rolled.

Patent leather is a leather that has a plastic coating applied to it. The process was invented by an American, Seth Boyden, in 1818.

Fish Skin Leathers

Leathers are made of the skins of various fish, including cod, perch, salmon, sturgeon, tilapia and wolfish. Leather is also made from eel skin. Leather made from stingray skin is called shagreen. Leather is also made from shark skin.

Leather made from unborn/stillborn calves is called slink.

Nubuck is grain cow hide leather sanded/buffed so that is has a velvety, suede-like exterior.

Deerskin produces a tough, abrasion-resistant leather.


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