The Designer’s Guide to Shoe Leather
What is the best shoe leather?
There are many different types of shoe leather. Entire books have been written on the subject of leather and how it’s made but we are just going to cover the basics you should know for sports and casual footwear design and manufacturing.
We are going to talk about real leather from animals! The most common are cow and calf leather, followed by pig, goat, sheep, kangaroo (for soccer cleats – if you believe that) alligator, ostrich etc. etc. We are going to focus on cow as it is by far the most common leather found in footwear and cow leather comes in many different styles, grades and prices.
Shoe leather starts as animal hide. During processing the hair is removed from the top or outer surface, and any remaining flesh and fat is removed from the inside of the hide. Following this operation, the hide is “tanned” (or you could say “pickled”) to preserve the fibers. New oils, preservatives and coloring are added. There are many ways to tan shoe leather. Tanning a hide into shoe leather involves a process which permanently alters the protein structure of skin making it stronger and resistant to decomposition. This can be a very wet and messy operation as the hides are tumbled in giant drums full of water, dyes and chemicals. This operation can take 10 or more hours. Tanning can be performed with either vegetable or mineral methods. We will not go into that here, but you should know you will have options. Other processes introduce fat to the leather to make it soft and pliable.
What is important to know is that the cow hide is thick and has two parts. First comes the top surface or “grain” part of the leather. This is the outside skin of the animal. The grain is the most valuable part of the hide. The leather fibers are dense, tight, and firm. The grain surface is also smooth. Second, as the depth increases into the animal hide, the leather fibers are looser and softer. These layers are called the “split,” “split leather,” “suede,” or “split suede.” It’s called split because a huge metal blade is used to “split” off the top grain, leaving behind the suede surface.
Grain leather or full grain is the most expensive. There are many ways to process this type of leather depending on its quality. Full grain leather can be processed to flatten the natural grain, treated to raise the grain, or embossed to have a completely different grain pattern. The grain surface can also be waxed, oiled, sprayed, painted, dyed, and polished to create different looks.
Common Types of Grain leather or Full Grain Leather:
Full Grain Aniline: A leather which has kept its full grain, has a naturally textured full pored surface. The deep aniline coloring is achieved with dyes. It may or may not have a thin transparent finishing coat. This leather is of the highest quality and is the most expensive. Only flawless skins undergo such a treatment. Not well protected, these leathers darken well with age.
Full Grain Pigmented (also called Top Grain): This shoe leather has also retained intact its full grain but has received a penetrating dye: a colored opaque finishing which gives a unified appearance, hides small defects, and protects the leather. Only high quality raw-hides are used. This treatment makes leather pleasing to look at and to touch, and makes it resistant. It’s the best compromise between esthetics and resistance.
Corrected and Pigmented Grain: To smooth out the leather surface and to hide its imperfections, wrinkles, scratches… the skin is slightly embossed and a tinted grain film is applied to its surface. These leathers are not of the highest quality and they have a slightly artificial appearance. The surface coating however, is quite resistant to heavy wear. This type of shoe leather is often used in service style boots. The leather will be water proofed or even blood proofed depending on the requirements. You will find this leather used to make steel toe boots for soldiers, police, and medics.
Nubuck: The velvety appearance of this leather is obtained by a light pouncing (or buffing) of the skin, thus highlighting the grain and the pores of the leather. To obtain a good looking nubuck, a quality skin is generally used. It’s a pleasant material, soft to the touch with velvety colors. However, nubuck is fragile and requires careful maintenance. A waterproofing treatment is mandatory. It remains a costly material. Nubuck and be oiled or post treated. Thickness ranges from 1.8 to 2.2mm. Price ranges from $2.00 to 3.00 depending on color and quality. Lighter colors require higher quality raw materials.
Crazy Horse: To make this style of leather, a lower quality full grain hide may be brushed to remove just the top surface. The leather is then treated with a heavy, waxy, and oily compound that will darken the leather. This is the rough and rugged style of leather – you may see scratches, bug bites, scars and fat wrinkles in the surface but that’s okay, it’s crazy horse. This leather will show color changes when flexed.
Split or Suede: The leather surface remaining after the top grain is removed. Suede is a very common shoe material. High quality short nap suede can almost have the appearance of nubuck leather. Lower quality suede may be a hairy, cardboard like, dusty off-color mess. Available in a rainbow of colors, quality suede is a stable material for casual, skate, and vulcanized shoes. Available in thicknesses between 1.2mm and 1.8mm. The most common suede is 1.4 to 1.6mm. Prices range from $1.05 to $1.45 USD per foot.
Pressed Suede: Starting with split leather the surface is treated with an oily plastic based resin. The leather hide is then pressed flat with an embossing plate. The surface will have a fine texture and may have a slightly glossy appearance. This is an inexpensive material, starting with lower quality hides. After some use the surface will crack and the suede fibers may show. This is not for fine shoes.
Action or Coated Leather: This leather product starts out as medium to low quality split leather. The surface may be pressed or rolled smooth. The hide is then laminated to a thin film of flexible stretchable PU or PVC. This synthetic surface is made by colored resin, white and black are the most common colors. The surface will be embossed which is done by pouring the plastic compound onto a sheet of textured paper. Once the fIlm and leather are bonded, the split has a very smooth full grain like surface. In fact, all the smooth white leather you see on sport shoes is this style of “action leather.”
This material is durable, the skin is waterproof, cuts clean and behaves just like full grain leather in shoe making operations. Action leather is less expensive than suede. Around $1.00 USD or a little less. This material is also easy for the factory to cut, there are typically very few scratches or scars showing that must be avoided. A very popular material for shoes, action leather is cheap, durable, looks good and comes in many colors and finishes. Action leather can look like full grain, nubuck and glossy patent leather. Finally, despite its plastic coating, action leather is still considered leather for duty classifications.
You can see there are a variety of leather types, prices, and features available. From fashion shoes made with white nubuck, to black blood-proof combat boots, leather is an amazing material for shoes.