Leather Glossary

Types of leather

Leather consists of intertwined collagen fibres (protein). Each collagen fibre consists of up to 2 million fibrils. The density of intertwining varies from species to species. But even within an animal skin, the density of intertwining differs significantly. A looser fibre structure is less resistant to tearing than a dense structure.https://www.leather-dictionary.com/index.php/Leather

Depending on the type of leather, type of tanning and type of colouration, tanned leather comprises 45 to 75% hide substance, 8 to 45% tannins, 1 to 25% oils and/or fats, up to 3% dye and pigment colour and 8 to 15% moisture. The tannins prevent the decay of the hide substance and oils, fats and moisture make the leather supple.

The most common kind of tanning is chrome tanning. Leather clothing and leather shoes are almost exclusively chrome-tanned nowadays. Chrome III is harmless and occurs in many food sources. Today's leather goods are well-regulated and, apart from rare exceptions, free of toxins.

Full grain leather 

Full grain leather refers to leather where the grain surface is still intact which makes the leather stronger and of higher quality. It traditionally has a thinner layer of pigment and coating, and because the surface has not been buffed, the natural flaws and characteristics of the skin visible.

Top grain leather 

is where the grain side of the leather has not been completely removed. It includes all types of smooth leather, including embossed leather and corrected grain. 

Nubuck, where the top grain is sanded and split leather, is not top grain leather.


Corrected grain

In preparation for embossing smooth leather, the leather is frequently sanded (buffed) first on the grain side to obtain a uniform surface and to make skin damages invisible. Subsequently, a binder-based colour layer is applied and a uniform grain embossed.

Such leather is then referred to as "Corrected Grain". It is cheaper and feels stiffer and colder due to the thick colour layer and the fibre compression of the embossing. It is also less breathable than porous leather.

There are also corrected grains, which are only slightly sanded and embossed and feel soft and warm. But they are rare exceptions.


PU leather 

is a split leather that has been laminated with a polyurethane coating to make it look like a top grain leather. Usually, these leathers have a glossy surface and an antique look. PU leather is used for furniture and shoes.


Split leather / Suede

If a skin is divided into several layers over the entire surface, this process is called "splitting". Thicker leather, mostly cow leather, which is 5 to 10 millimetres thick, is split. The obtained layers are designated as grain split or top-grain split and flesh split. Sometimes, the leather is thick enough for a middle split. The split, separated from the grain split, is also called drop split. The drop-split leather is rough on both sides like the back of a leather.

Types of graining

fine pore leather - coarse pore leather - fine grain leather - coarse grain leather

The original grain pattern already differs on the same animal skin surface. In the middle of a skin, the leather is mostly fine-pored, and towards the edge it becomes more coarse-pored. The appearance of an even skin structure is often disrupted by deeper natural wrinkles.


On same skin: fine pored -> transition -> coarse pored.

Corrected Grain 


In preparation for embossing smooth leather, the leather is frequently sanded (buffed) first on the grain side to obtain a uniform surface and to make skin damages invisible. Subsequently, a binder-based colour layer is applied and a uniform grain embossed.

Such leather is then referred to as "Corrected Grain". It is cheaper and feels stiffer and colder due to the thick colour layer and the fibre compression of the embossing. It is also less breathable than porous leather.

There are also corrected grains, which are only slightly sanded and embossed and feel soft and warm. But they are rare exceptions.

Embossed leather

Embossing is the art of producing raised patterns on the natural grain of an animal skin. The design is created by pressing rolling or stamping. Embossments can cover the entire surface of a skin or just selected areas.

Another reason for embossing hides is to obscure natural markings on leather. Therefore, the surface is sanded and repaired before embossing. Such leather is called ‘corrected grain’.

A farmer doesn’t get any more money from the butcher for his cows and cattle, if the skin is flawless. During their lifetime, animals suffer wounds and marks that affect the quality of the leather surface. Embossing is used to hide insect bites, injuries, illnesses, and other damages on animal skins and to create a uniform grain.

This reduces wastage, as the entire surface of a skin gets a uniform grain pattern. All parts of a set of furniture or car interiors will be identical. Minor flaws and irregularities of the natural grain can be balanced and must not be circumvented when cutting the leather.

Unembossed leather

For any tannery, the scale of costs depends on the number of hides which can be used. Skins that are not good enough for processing as full-grain leather can be embossed. Only about 10-20% of the hides coming from the slaughterhouse are ‘good’ to ‘very good’ quality. Embossing does not reduce the quality of the leather. Provided that it is not hiding damage that could affect the life expectancy of the leather, embossing is perfectly acceptable.


Dyed leather

After tanning, most leather is first dyed through completely. This is done in dye stuff (liquid dye like ink for colouration of textiles). For this purpose, the leather is immersed in a dye bath in rotating barrels (= drum dyed). The dye has to be fixed and excess colour has to be rinsed out to prevent dye transfer from leather.

Aniline dye is a transparent liquid which is absorbed by the leather without forming a coating layer. All absorbent leather types (suedenubuck and aniline leather) are dyed this way. Top-grained absorbent porous leather is called aniline. But also, most pigmented (with coating layer) leather is first dyed through.

Since these dyes are transparent, they can only be used to dye a darker shade. Aniline dye is usually referred to as "aniline colour".

Structure of the leather colouring and finish. Without finish = aniline leather.

Pure aniline leather: 

Pores are completely visible and there is no finish on the leather.

Semi-aniline leather: 

Pores are clearly visible, but a thin layer of paint is on the leather surface.

Pigmented smooth leather: 

Pores are no longer distinguishable. The leather has a thick layer of paint.


Finishing determines the appearance of the final surface of the leather and the surface properties. This includes colouring, waterproofing, wax dressings, but also mechanical processing stages such as ironing or embossing of the leather.

Finishing with pigment-containing leather colours

To make leather more durable, more stain-resistant and permanently water-repellent, a layer of a binder-pigment-mixture is applied to the surface of smooth leather that has already been completely pre-coloured with aniline dyes. This colour coat is also called finish or pigmentation. Motorcycle suits, but also many leisure jackets, shoes, car, furniture and bags made of smooth leather have this protective colour layer. These leathers are then referred to as pigmented leather or finished leather.

Smooth leather without this colour layer is called aniline leather. Leather with a very thin finish is called aniline leather, refined or semi-aniline leather. Smooth leather with a finish layer of more than 0.15 millimetres in thickness - whether colour or foil - must be declared as coated leather in Europe.

The advantage of aniline leather is a warm feel and naturalness and the main disadvantage is the sensitivity. Pigmented leather feels colder and firmer, but is significantly easier to clean and care for and less sensitive. Pigmented leathers also have lower breathability properties than porous leather.

There are also leathers which have an oil coating or wax coating. For these leathers, uncoloured or dyed waxes and/or oils are applied to the leather surface. Such leather is called pull-up leather.https://www.leather-dictionary.com/index.php/Finish


Primer – Finish / Top Coat

A primer is first applied to promote adhesion. The top coat, a kind of clear protective coating, is then applied to the subsequent colour layer. Top coats protect the binder colour from abrasion and discolouration and determine the degree of gloss and the haptic. Crosslinkers provide improved fastness as additives. In case of particularly matt leather, a duller is added to the top coat and/or to the colour. Vehicle leather is often very matt and leather-covered dashboards must be particularly matt because of the risk of reflections in the windscreen.https://www.leather-dictionary.com/index.php/Finish