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Technical Glossary

The following terms are commonly used to explain the various types of leather and their treatments on the market today.

Aniline leather

Aniline leather is a type of leather that has been soaked with a chemical dye called aniline. Only the best quality leather hides are selected for use as aniline leather, making it the most expensive of all types.  

Aniline leather is commonly found in two forms: ‘full aniline’ and ‘semi-aniline’:

  • Full aniline refers to aniline-dyed leather which doesn’t have a top pigmented finish coating applied to its surface. As a result the leather retains many of its natural characteristics: it is able to naturally breathe, helping it remain soft and flexible, and is also cool to the touch. However, lacking a coating also means that the leather is porous, unlike semi-aniline, and more susceptible to absorbing water.
  • Semi-aniline is aniline-dyed leather which does have a top pigmented finish coating applied to its surface, helping it be resistant to spillages and water absorption. The light protective coating, which contains a small amount of pigment, is thinly applied after dyeing to ensure consistency of colouration whilst allowing the leather’s natural grainy appearance to show through.

Corrected grain

Corrected grain leather is used in the manufacture of boots, clothes and furniture. The grain of the leather is smoothed and given a textured grain for a more consistent look. Although slightly more rigid than pure aniline leather, corrected grain leather becomes softer through use.

Coated leather

Coated leather is defined as “a product where the surface coating applied to the leather substrate does not exceed one-third of the total thickness of the product, but is in excess of 0.15mm”.  As the finish thickness exceeds 0.15mm the material cannot be classed as genuine leather. Coated leather grain is coated with various chemical materials, such as a polyurethane mix, and used mainly for handbags and belts as well as for upholstering furniture.
The main benefits of the material is that it is economical to produce and has a uniform, wipe clean surface. However, this also gives it a more man-made look.

Coated splits

Split leather is formed from the lower (inner or the flesh side) layer of a hide, which has split away from the upper, or grain layer. The leather is split during tanning before usually being given a suede or pigment finish and buffed to smooth the surface. Finally, for added durability, it is coated with urethane. Coated split leather is more economical than other types of leather and has a thick and firm feel but is more brittle than full-grain or side leather.

Embossing and added pigmentation can be applied to coated splits and its main uses include business cases, leather accessories, in addition to upholstered furniture.

Surface treatment

This covers a wide range of treatments to the surface of the leather including dyeing, buffing of the grain for added smoothness or to create a base for adding artificial grain, the mechanical application of grains, and the coating of chemicals like Polyurethane (PU) to make the surface more durable and easier to clean. Conversely, ‘unfinished leather’ describes leather, which has been tanned, but has not had any surface treatment.  

Faux/synthetic leather

Faux leather, or synthetic leather, imitates leather and is used in upholstery, clothing and fabrics as an economical alternative to traditional leather. It is not always entirely man-made, as most people think, and can include some leather in its composition. However, the amount of leather is insufficient for it to be defined as ‘real leather’. In order to create a leather look, various polymers are blended with the leather. The leather is graded according to the amount of polymers used – more polymers mean a lower grade. Compared to real leather, faux leather is shinier, stiffer and warmer, and has an artificial rubber-like scent rather than the natural smell of traditional leather. On the plus side, faux leather is strong, durable and easy to clean.

PU- and PVC-coated textiles

Polyurethane (PU) is used as a durable coating to give textiles a wide variety of properties including the ability to be waterproof, stain-resistant, anti-bacterial, anti-fungal and flame retardant.

In PU-coated leather, the coating is used to enable the leather to be resistant to water and scratches. The coating also helps the leather to be quick to dry, soft and durable whilst also allowing patterns to be embossed, if desired. PU-coated leather is commonly used for the upper for shoes and in upholstery.  

‘Leatherette’ is a type of synthetic leather, often by covering a fabric substrate with a soft PVC plastic layer. Among its main benefits compared to leather is that it is low cost and needs little maintenance. However, it is not porous and may burn more vigorously than leather.

Recycled wet blue

Wet blue is used to describe leather (normally blue in colour, hence the name) that comes straight from tanning and has had no other treatments.

The fibres of off-cuts and trimmings from wet blue waste leather are recycled and used to create more ecologically sound forms of leather like composition leather. The process of making composition leather is eco-friendly as it recycles waste leather that is normally sent to landfill and uses just water alone (rather than resins and glues unlike bonded leather) to bind the fibres together. The fibres are combined with a high-tensile textile core and sealed to maintain strength and durability.