WHAT IS LEATHER?
- Leather processing is very complex. After removing the leather skin from the beast they are salted immediately to prevent initial bacteria growth. The skins are then sent from the abattoir to the tannery.
- Once the hides have arrived at the tannery the following process takes place. The leather is soaked in a Chromium Sulphate Solution to clean the raw hide.
- The leather hide is then soaked in a Liming solution to open the fibres of the leather for the ease of removing the hair and unwanted part of the hide. This also kills all the bacteria.
- The next step is to mechanically split the hide so that the hide is clean and even all over. (This is also known as fleshing).
- Once this is done the leather is de-limed to remove the unwanted chemicals from the liming process.
- The leather hide is then put through another wash of acids and solvents so as to make it clean and ready for tanning.
- The tanning process is now ready to begin.
Preservation by cross
Linking the fibres (also known as tanning). This is achieved by either mineral, aldehyde or oil and vegetable tanning (Mineral Tanning is commonly used for Upholstery Leather).
Samming or squeegeeing
Samming or squeegeeing the water and chemicals out of the leather.
A splitting machine slices thicker leather into two layers. The layer without a grain surface can be tuned into suede or have an artificial grain surface applied.
Adjusting the thickness of the leather. So that the leather have more even surface and tickness.
They may now re-tan again to adjust the various features in the leather or neutralise the chemicals from the leather and continue with the processing.
Dyeing of the leather for desired colour. This is mostly done with penetrating dyes, although some leathers are only surface dyed.
Fast liquoring is a type of treatments of fats and oils to adjust the leather’s softness.
Mechanically softening of the leather.
Buffing & Brushing
In some cases, the grain surface is buffed to produce a very fine nap, example nubuck leathers.
Applying more pigments and binders and also polyurethane finish coats as well as correcting the grain surface. (Also known as embossing).
Smoothing out the top-coats.
This will depend on colour intensity, uniformity, feel, thickness, appearance and natural marks on the hide.
Types of Upholstery Leather
Full Grain Leather
This cut of leather contains the outer layout of the hide, referred to as the “grain”; it hasn’t been sanded or buffed to remove any imperfections. Generally, only the hair is removed on full grain leathers. The grain generally has densely packed fibers that are finer; this results in a surface that is very strong, durable, and can withstand tough use.
Those surface fibers are also what give it the most strength of any leather type. This makes it good for furniture. Since the outer layer isn’t removed, it develops a patina (a surface color change from use) over time that can be pleasing to the eye. The outer layer also provides some water-resistance qualities as well. Full Grain is looked upon as the highest quality leather available.
Top Grain Leather
This cut is very similar to full-grain, except that it has had the very top layer sanded and/or buffed to remove imperfections and irregularities in the finish. This makes the leather softer and more pliable, with various dyes and finished applied to it.
While this sanding makes it more visually appealing, it also removes a lot of the strength and some water-repellent qualities of full grain leather. This we begin to see a tradeoff between leather strength, and leather look and softness.
Given its softness and flexibility, top grain leather is often used in high end leather goods, including furniture, handbags, wallets, and shoes.
Genuine Leather (Corrected)
Genuine leather can come from any layer of the hide, and undergoes treatment to the surface to provide a more uniform, “corrected”, appearance. It can be sanded or buffed to remove surface imperfections, then dyed (or spray painted) or stamped/embossed to give it a final surface appearance.
The process alters some of the preferred qualities of leather, so while not a top quality, it is often used for belts and similar goods.
Split Grain Leather
Split grain leather is a layered cut of leather from within the lower levels of the top grain area of the hide. It is usually a lower layer of the hide, above the flesh. Also, below the full grain and the best top grain cuts. Though, it still provides a useful leather material.
The natural surface of split grain leather is not as dense, tight, and useful as full grain and top grain. Thus, it is often used in finishes of leathers that are colored, embossed, and the surface altered in some significant way. This allows it to offer some of the helpful qualities of a leather material, while having a visually pleasing and often-functional surface beneficial for leather products.
Bonded Leather (Reconstituted Leather)
Bonded leather is like the scrapple or hot dogs of leather; it is made up of leather scraps that are finely shredded and bonded together using polyurethane or latex onto a fiber mesh or sheet. The amount of leather in the actual mix can vary greatly (from 10%-90%), and thus affect the functional and aesthetic properties of the finished product. Bonded leather is often painted to give it color and could also be pressed/embossed to give it the appearance of a particular grain or leather style.
Types of Leather Finishes – Finished Leathers
Aniline leather is a type of leather dyed only with soluble dyes. They allow the natural surface of the leather to show through (blemishes, cuts, etc.). Generally only higher quality leathers are used since they have nice, even surfaces.
It is then finished with a thin protective coating to help prevent fast wear of the leather, or any other staying or discoloration from showing up on the surface.This can be a visually appealing dye approach, since it does allow the original surface of the leather to show through.
Semi Aniline Leather
Semi-aniline leather is a type of leather that is dyed only with soluble dyes. It is similar to aniline leather, though it is only slightly pigmented. Semi-aniline leathers allow the natural surface of the leather to show through (blemishes, cuts, etc.).
It is then finished with a thin protective coating to help prevent fast wear of the leather, or any other staying or discoloration from showing up on the surface.Generally only higher quality leathers are used since they have nice, even surfaces. This can be a visually appealing dye approach, since it does allow the original surface of the leather to show through.
Antique Grain Leather
Antique grain is a type of leather that has been treated with a surface affect to give an aged and worn appearance. It might involve several tones of finish, or a rubbed patten to mimic wear over time. Antique grain leather allows one to utilize an aged look in their finished product, without requiring the leather to be very old or worn out.
Bicast is a type of leather made with a split leather backing and an embossed/impressed layer of polyurethane or vinyl on the top. This gives the appearance of a patterned/shiny leather, without the cost of a true top or full grain leather piece.
Faux leather is a type of synthetic leather made generally of polyurethane or vinyl. Faux leather is intended to look like real leather yet cost significantly less. It is used often in the furniture industry and has the benefits of being inexpensive (compared to real leather), durable, and easy to clean.
It does however not reflect real leather qualities such as wearing better over time, having natural stretchability, breathability, and resistance to cuts and other abrasions, and a unique natural look/feel.
Faux leather can be referred to by a number of names, which can include:
- Faux Leather
- PU Leather
- Vinyl Leather
- Vegan Leather
Nubuck is a type of leather that is a top-grain leather that has has the surface sanded in such a way as to leave the surface with a slight nap of short protein fibers. This produces a soft, velvet-like surface that is pleasing to touch, and also has a unique visual appearance. Nubuck leather is often used in jackets, gloves, and accessories.
Oil Leather (Pull-Up Leather, Waxy Leather, Waxed Leather)
Oil Leather, also known as pull-up leather, waxy leather, and waxed leather, is a type of leather that has a larger volume than average amount of oils and waxes in the surface finish. When the leather pieces are flexed and moved, the surface catches the light in different ways, do to the reflections on the oils and waxes. This provides for a varied look across surface tones, which could be quite visually appealing.
Pearlized Leather is a type of leather that has had a liquid layer of color added to the surface during finishing. It provides for a soft, subtle shine and reflection to the leather. While not as reflective as metallic leather, pearlized leather is a subtler implementation of the same concept. It is popularly used on clothing, accessories, and handbags.
Pigmented leather is a type of leather that is finished with a top coat of pigment (or paint). That pigment helps both provide an even surface on the leather, and also a protective coating. Pigmented leather is often coated with a clear protective sealer, to help protect the pigment layer.
Suede is a type of leather made using a similar approach as Nubuck, where the surface is sanded in such a way as to leave the surface with a slight nap of short protein fibers. Though, instead of being made from full grain leather, suede is made from split grain leather.
Patent leather is a type of leather that has a high-gloss finish applied via a coating, generally linseed oil. It was developed in 1818 (by inventor Seth Boyden in Newark, New Jersey). Patent leather finishing is often very noticeable with a highly-reflective finish. More modern patent leather replaces the linseed oil finish with a plastic coating finish.