About Leather

Glossary

ANILINE

• The name of a dye used to colour leather, penetrating the hide throughout.  Non toxic dyes are used.
• Aniline is not a type of leather but is often used to describe sensitive leathers.
• Aniline dyed leathers will be the same colour throughout unless a pigment or other substance has been used to colour the top surface.

ANILINE DYED

• Process of colouring leathers throughout using coloured non toxic dyes.
• The correct name for ‘Aniline’ leather.
• The leather has been through-dyed in a dye bath (drum dying) but as it is so sensitive in its natural state it often receives extra surface treatments in order to make it more serviceable.

ANTIQUING

• The application of a contrasting colour (usually darker) over a base colour on the surface of the leather to accentuate the natural grain or embossing.
• May be applied by hand (rub-on or hand-wipe) or machine (spray effect) or rub-off (a process of coating then removing by hand to achieve the antique effect).

BI-CAST

• A split leather with a polymer coating. 
• The polymer coating is created as a separate layer and then applied with adhesives, rather than being applied by spraying several thin coats as in ordinary leather.  This results in a very even finish on a leather of generally poor quality. 
• The thickness of the polymer layer will determine whether it can be sold as leather or re-categorised as leather laminate.

BUFFED

• Leather which has been smoothed by mechanical sanding to get rid of faults in the leather surface before finishing and embossing.

CHROME TANNING

• 99% of all upholstery leather is chrome tanned. 
• Chrome tanning involves drumming the hide in a bath of chrome liquor. After this process the hide is termed ‘wet blue’ leather.

CORRECTED GRAIN

• This is where a grain pattern has been applied to the leather surface by mechanical means. Sometimes it will be applied to a Full Grain Leather to enhance or change the original grain; other times the surface will be buffed to some degree and the pattern will be used to create a better pattern over what remains of the original. It differs from embossing in that no stucco or filler is used to support the pattern creation.
• The process is usually applied to leathers that will be finished in some way (pigmented, protected…).

CORRECTED LEATHER

See Corrected Grain

CROCKING

• Transferring of a colour or finish from leather to other material by rubbing or abrasion.

CRUST

• Leather that has been through the tanning process, aniline dyed, milled and dried, but with no surface finish at all.
• Rarely used for furniture as it is so sensitive and impossible to clean or repair without leaving evidence.

DRUM DYED

• A dyeing process in which the leather is immersed in dye.
• The leather is placed in a drum with dyes and tumbled to ensure the complete absorption of colour.

DYE TRANSFER

• The term used when dye stuff from clothing, newspaper etc. transfers to leather. Although it can happen to all leather it is most noticeable on off-white and other pale leather.
• Although it is not harmful to the leather in a structural way, it can be unsightly as it appears to be dirty.

• If left untreated it can be very difficult to remove and may have to be coloured over as a last resort.

EMBOSSING/EMBOSSED LEATHER

• Creating a motif or texture on the leather.
• This is done by impressing a pattern onto a surface that has been prepared by buffing (to remove damage and poor appearance) and coating with filler or stucco.
• Generally on lower quality leather but not exclusively.

Also see Corrected Grain.

FAT LIQUORING

• The process of replacing oils and fats that have been leached from the hide during the tanning process.
• Often referred to as Re-tanning, the process allows the hide to be softened.

See also Spewing.

FAT WRINKLES

• Natural wrinkles in the leather that are a part of the unique qualities in the hide, similar to stretch marks.
• They are most visible on full grain leathers and are an indication of a good healthy (fat) animal.

FINISHING

• This term encompasses all procedures that are carried out after the tanning and initial dyeing process.
• These may include rolling, spraying, waxing, milling, buffing, embossing, antiquing, and the adding of any protective finishes.

FULL ANILINE

• Leather receiving its colour from aniline dyes.
• May however have top coats of wax or oil.

FULL GRAIN

• This refers to the top grain section (as opposed to the split) of the leather that has had nothing removed by buffing or sanding.
• Usually only lightly finished as it will be top quality but can be fully finished.

GRAIN

• The outer surface of a hide or skin.
• It also refers to the pattern of the outer surface after the hair has been removed.
• The grain maybe very natural as in Full Grain or may be an imitation achieved by grain correction or embossing.

HAND

• Term used to describe the feel or degree of softness of a hide or skin. It is not a measurable term.

HIDE

• Term used for the skins of large animals such as cows, buffalo, or horse.

HYDROPHOBATED

• Leathers which have been hydrophobated have been treated to make them more resistant to water.
• Hydrophobation does not help in resisting anything other than water.

LEATHER

• Skin or hide can only be called leather after it has been put through the tanning process which turns it into a non-perishable material….leather.

LIMING

• The process of removing the hair from a raw hide through the use of chemicals (Lime or derivatives of..).

MATT FINISH

• A finish applied to leather that has had its reflective properties reduced which will make it appear matt or dull to some degree (semi-matt…)

MICRO-PIGMENT

• This type of leather has a fine spray of pigment added to it to limit the natural hue variations of aniline dyed leather or to create particular type of finish effect. The pigment and finish used will not be heavy enough to coat the leather so it will still retain the soft hand of aniline and remain quite porous.

MILLING

• Process in which tanned hides are tumbled in rotating drums usually as a softening process during the tanning and finishing process.

NAKED LEATHER

• A tanned aniline dyed leather with no surface treatment in its true form but usually has some extra aniline or light finish product on the surface to increase its serviceability.
• Commonly referred to as ‘Pure Aniline’

NATURAL GRAIN

• Leather whose grain has not been altered in any way and the natural appearance of the grain is apparent.

NITRO-CELLULOSE

• A finish which is applied to Aniline leather. 
• Nitro-cellulose finish is not the same as a polyurethane finish. It is less durable than polyurethane, but it is softer and retains many of the aesthetic characteristics of Aniline leather.

NUBUCK

• A Top Grain Aniline dyed leather with a ‘suede like’ nap effect created by lightly buffing the surface.
• The finest quality Nubuck would retain the full grain pattern of the leather; poorer qualities are more heavily buffed.

PEARLISED

• A special finish created by adding a fine reflective powder (usually gold or silver in colour) to the finishing product.
• The effect is a slightly reflect quality that shows slight colour changes with changes in light direction. 

PIGMENTED

• Leather whose surface is coated with a material containing pigment or other opaque materials as a colouring process. It will then be sealed with a polyurethane style coating.
• May also be known as Protected.

PLATED/PLATEING

• The flattening or ironing of the leather to smooth out its natural grain pattern. It gives the leather a very fine appearance.

POLISHING

• Removal of the grain, scars and blemishes from a hide.
• May also be known as buffing.

PROTECTED

• Usually refers to leathers that are pigment coloured and sealed with lacquers.
• A better definition would be a leather that does not readily absorb moisture so would be more resistant to absorbing stains. Cleaning products remain on the surface and are active for longer and are therefore more effective.
• May also be known as Pigmented.

PULL-UP

• The term Pull-up, (we think….if anyone knows differently please contact us) refers to the upholstery term pulling the covers up onto the frame! When this was done with this type of leather the colour ‘pulled out or faded’!
• Generally they are an aniline dyed leather with a wax or oil surface treatment. Often the finish product will have some colour content as well, the stronger this is the more dramatic the colour change will be. Also as the waxes and oils are not fixed they scratch very easily, although this is very easily remedied and is deemed a feature of this leather type.
• Modern ‘pull-up’ leathers are not now purely wax or oil but have additional finishing agents to make them more resistant to the pull-up and scratching received during use. Unfortunately this also makes them more difficult to restore when they are damaged or worn.

PURE ANILINE

• Leather which receives its entire colour from dyes only and exhibits natural markings and characteristics.

RE-TANNING

See Fat Liquoring

SAUVAGE/KELA

• A two-tone effect which adds depth and character.  Can be tone-on-tone or a contrasting effect.
• Usually protected type or micro-pigment but there will always be exceptions.

SPEW

• When the fat liquor introduced during the re-tanning process is destabilised and rises to the surface of the leather creating a white haze or film on the surface. 
• This will look dry but have a greasy/fatty feel to it. If it is cleaned off it will almost certainly return.
• Requires a stabilising product to re balance the fats.

See also fat liquoring or re-tanning.

SPLIT

• The split of a hide is the lower part when the top grain (hair) side is cut (split) off.
• It is of poorer quality than the top grain and when processed should not be used    in high wear areas of furniture. Because the grain has been removed the split has no natural features or grain pattern, so its surface has to be prepared and embossed to give a ‘leather’ or ‘top grain’ appearance. As the fibre structure is looser than the top grain it stretches more and lacks the elasticity of top grain to return to shape. It will tear much more easily even after coating.

See Bi-cast for another use of split leather.

SUEDE

• Suede comes in two versions:-  Hunter Suede and Split Suede.
• Hunter Suede is any piece of top grain leather reversed, so will be the same quality as the piece of leather without the issue of surface scarring etc. being of significance.
• Split Suede is unfinished split leather, so will be of poor quality.
• The colour of suede comes from the aniline (or through) dying of the leather.
• The surface of suede will be of a more course texture than Nubuck, be careful not to confuse the two.

TANNING

• The process of turning raw hide or skin into the product called leather.
• This process uses tanning agents to convert the hide into a stable non-perishable material.

See also Chrome Tanning

TOP COAT

• Synthetic transparent or coloured polyurethane resins applied as a protective coating producing a high gloss, semi-gloss(satin) or matt finish.

TOP GRAIN

• The outermost layer of the hide which is left after the splitting of the hide into layers.
• The top grain of the hide is strong, flexible and the most breathable part of the hide. It is also the part of the hide which will show the life of the animal through natural markings.
• Top Grain, depending on its quality and its intended market, may be either natural (full grain), corrected, or embossed

TUMBLING

See Milling

UNFINISHED LEATHER

• Leather that has been tanned, but to which no surface treatment has been applied. 

See Crust Leather

WET BLUE

• The name given to leather immediately after it has been tanned, but has had no other treatments. It is usually pale duck egg blue (hence the name) and very stiff. In this state it completely unworkable for upholstery use and has to go through re-tanning and finishing stages.