Aniline Dye
A transparent, water-based dye originally derived from the indigo plant, but now made synthetically. It is used to color leather hides by permeating them entirely in a drum-dyeing process. Aniline dye can also be sprayed onto the surface of leather after the drum-dyeing as to "finish" the leather.
Antiqued Leather
Leather that is treated to have an antique look. It is produced by applying a black or contrasting color to the surface of the hide by machine or by hand. The wash seeps into the valleys of the skin, producing a two-tone effect that emulates the natural signs of aging.
Bovine
An adjective referring to an animal belonging to the cattle or ox family.
Buffed Leather
Leather from which the grain is removed by an abrasive or bladed cylinder, or with sandpaper. The buffing process is used in altered or corrected grain leather to remove surface defects. It is sometimes referred to as "snuffed" leather.
Chromium-Tanned Leather
Leather that is preserved, or tanned, in a chromium salt solution, resulting in soft, flexible hides that are receptive to penetration by any color.
Combination-Tanned Leather
Leather that is first chrome-tanned and then vegetable tanned. The result is a leather that has the best properties of both types of tannage: the suppleness and light weight required for upholstery, and the hand and firmness of vegetable-tanned leather.
Corrected Grain Leather
Sometimes referred to as top grain leather, corrected leather has had its surfaced buffed to remove superficial defects. It is usually sprayed superficially with pigmented dyes, then embossed with a natural-grain pattern to replace the texture that has been removed.
Crust
Unfinished leather that has had its hair removed and has been chromium tanned to prevent putrefaction while it is stored while awaiting the drum-dyeing and finishing processes.
Distressed Leather
Sometimes called "pull-up" leather, it has been treated to look worn and used. It is produced by applying transparent heat-reactive oils and waxes to the surface of pure aniline-dyed leather, then dry-milling the hides to create a two-tone, crackled appearance. When stretched or pulled, separation of the waxes/oils occur, resulting in contrasting color, becoming lighter in the pulled areas. The result is a worn in effect.Drum Dyeing
The process during which leather hides are tumbled in a drum for up to 24 hours while submersed in an aniline-dye solution. During the milling process, the hides absorb the dyes from back to front for 100% saturation.
Embossed Leather
Leather that is embossed under heat and pressure as one of the last steps in the finishing process. The embossed pattern is used either to apply a natural pattern to leather that has been corrected, or to create afaux pattern, such as alligator, floral or geometric.
Finish
The final topcoat applied to leather to determine its ultimate look and function. It can render a hide shiny or matte, perfect the color, and add additional fade and stain resistance to the surface of the leather.
Full Grain
Leather whose surface is in its original, untouched condition. As a result, the natural peaks and valleys of the hide, as well as the tiny hair sacs from which the hair has been removed, are visible to the naked eye.
Grain
The surface of the leather, the grain refers to the leather’s hand, and indicates whether the leather has been corrected or is full grain.
Hand
The hand describes the actual feel of the leather to bare hands in terms of softness, suppleness and finish.
Hide
Animal skin with or without hair that has been tanned or dried for human use. The term applies only to animals with a shoulder height of one meter or more.
Leather
An animal hide that has been tanned with chemicals to preserve it and make it suitable for use as clothing, furniture covering, footwear and accessories. The most common leathers come from cows, sheep, goat, buffalo and pigs.
Milling
A "dry" process in which hides are tumbled in an empty vat or drum to make them more soft and supple.
Naked Leather
Sometimes called unfinished leather, this is leather that has been aniline-dyed in the drum but has not yet received a finishing topcoat. Certain leathers such as suede, nubuck and pure anilines are considered naked. They are more susceptible to fading and staining than leathers with a topcoat.
Natural Grain
A leather whose surface is untouched, resulting in the natural skin surface, with visible hair cells from which the hair has been removed, and a subtle, but uneven texture through the hide.
Nubuck
An aniline-dyed, full-grain leather produced by drum-dyeing the hides, and then brushing them with a fine sandpiper to produce a velvet-like surface with a luxurious nap. Some nubuck leathers are embossed to create a deep, textured look.
Patina
A natural characteristic that gradually develops over time on the surface of leather as skin oils and environmental elements are absorbed. It tends to occur on natural leathers more than leathers with pigment in their topcoat.
Pigmented Leather
Leather whose surface has been sprayed with an oil-based dye, usually to cover blemishes and add additional protections.
Rawhide or Raw Material
Stiff and untanned or partially-tanned hide.
Semi-Aniline Leather
Leather whose surface has been superficially sprayed with a combination of aniline and pigmented dyes to enhance durability and achieve a uniformity of color throughout the hide.
Split Leather
Leather made from the bottom or center split of a hide, then finished with a heavy pigment and embossment to imitate the grain surface of the leather. It is a less valuable part of the hide than the grain surface.
Strapping Leather
Heavyweight, vegetable-tanned leather used for industrial purposes or to support seats and backs on certain types of seating.
Suede
The center or bottom split of a hide that has been buffed to create a soft, nappy surface.
Tannin
Any plant-based solvent, usually derived from tree bark, used to preserve raw leather by stabilizing it and preventing putrefaction.
Top Grain
Sometimes used inaccurately to refer to the surface of leather, “top grain” is often a euphemism to imply the leather is other than full-grain, meaning that it has been corrected.
Vegetable Tanning
The ancient process of tanning, or preserving, leather hides, it converts rawhide into leather by soaking the hides in a bath of vegetable tannins and liquids. The result is leather with greater thickness and firmness than chromium tanned leather. Typically used for belts, wallets, shoes, handbags and saddlery, it is not suitable for upholstery due to its thickness and lack of pliability. 100% vegetable tanned leather does not accept all colors and is only available in shades of tan and brown, the natural color of tree bark.
Weight
This measure of a leather’s thickness in ounces is based on a calculation of the leather’s weight per square foot. Each ounce weighs 1/64”, the equivalent of 0.4 mm. The average thickness of upholstery leather is 1.0 to 1.1 mm, or the equivalent of between 2 to 3 ounces.
You may find this article on measuring fabric useful as well.