Leather 101

Common Terminology

Source: Wikipedia
  • Vegetable-tanned leather is tanned using tannins and other ingredients found in different vegetable matter, such as tree bark prepared in bark millswoodleavesfruits, and roots. It is supple and brown in color, with the exact shade depending on the mix of chemicals and the color of the skin. It is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water; it tends to discolor, so if left to soak and then dried it shrinks and becomes harder. In hot water, it shrinks drastically and partly congeals—becoming rigid, and eventually brittle. Boiled leather is an example of this, where the leather has been hardened by being immersed in hot water, or in boiled wax or similar substances. Historically, it was occasionally used as armour after hardening, and it has also been used for book binding.

  • Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and other chromium salts. It is more supple and pliable than vegetable-tanned leather and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium. More exotic colors are possible when using chrome tanning. The chrome tanning method usually only takes a day to finish, and the ease and agility of this method make it a popular choice. It is reported that chrome-tanned leather adds up to 80% of the global leather supply.

  • Oil Tanned Leather, The term 'oil tanned' is a misnomer. What we often call 'oil-tanned' is actually just oil-treated. Special purpose oils are applied on the surface of chrome tanned leather (or even veg tanned leather in special cases) at the end of the tanning process. The oils provide protection as well as a unique look to the surface.
  • Leather, usually vegetable-tanned, can be oiled to improve its water resistance. This currying process after tanning supplements the natural oils remaining in the leather itself, which can be washed out through repeated exposure to water.
  • Hot Stuffed,  Vegetable or Chrome tanned leather that is dipped into hot mixture of oils, tallows and waxes to deeply penetrate  the leather with the benefits of the protective nature of the hot mix.

Types of Leather

  • In general, leather is sold in four forms:

    • Full-grain is the highest quality leather you can buy. Full-Grain leather refers to hides that have not been sanded, buffed, or snuffed (as opposed to top-grain or corrected leather) to remove imperfections (or natural marks) on the surface of the hide.[1] The grain remains allowing the fiber strength and durability. The grain also has breathability, resulting in less moisture from prolonged contact. Rather than wearing out, it develops a patina during its expected useful lifetime. High quality leather furniture and footwear are often made from full-grain leather. Full-grain leathers are typically available in two finish types:anilinesemi-aniline.
    • Top-grain leather (the most common type in high-end leather products) is the second-highest quality. It has had the "split" layer separated away, making it thinner and more pliable than full-grain. Its surface has been sanded and a finish coat added, which produces a colder, plastic feel with less breathability, and it does not develop a natural patina. It is typically less expensive and has greater stain resistance than full-grain leather if the finish remains unbroken.
    • Corrected-grain leather is any leather that has had an artificial grain applied to its surface. The hides used to create corrected leather do not meet the standards for use in creating vegetable-tanned or aniline leather. The imperfections are corrected or sanded off, and an artificial grain embossed into the surface and dressed with stain or dyes. Most corrected-grain leather is used to make pigmented leather as the solid pigment helps hide the corrections or imperfections. Corrected grain leathers can mainly be bought as two finish types: semi-aniline and pigmented.
    • Split leather is leather created from the fibrous part of the hide left once the top-grain of the rawhide has been separated from the hide. During the splitting operation, the top-grain and drop split are separated. The drop split can be further split (thickness allowing) into a middle split and a flesh split. In very thick hides, the middle split can be separated into multiple layers until the thickness prevents further splitting. Split leather then has an artificial layer applied to the surface of the split and is embossed with a leather grain (bycast leather). Splits are also used to create suede. The strongest suedes are usually made from grain splits (that have the grain completely removed) or from the flesh split that has been shaved to the correct thickness. Suede is "fuzzy" on both sides. Manufacturers use a variety of techniques to make suede from full-grain. A reversed suede is a grained leather that has been designed into the leather article with the grain facing away from the visible surface. It is not considered a true suede.[2]