But First, an Introduction to Leather

Primitive people mainly used animal hides as a protection from the elements, primarily acting as a byproduct.  Once the meat was eaten, they would clean the skin and wear the leather on their bodies as a shield.  The smaller hides were fashioned into footwear.

The problem of skin pelts drying out soon arose.  Preservation, and softening tactics were discovered in order to slow down the the inevitable decay of the hides.  In the beginning, the skins were stretched out underneath the sun in order to dry.  Stiffened pelts were problematic, but it was no doubt that they lasted much longer.  As time passed, it was discovered that treating the dried out hides with various oils softened them.  Certain tree barks contain tannin which helps convert raw skins into the natural leather you and I see on a daily basis.  The specific date of the tanning method materializing is ambiguous.  the famous "Iceman" dating from at least 5,000 BC discovered in the Italian Alps several years ago, was clothed in very durable 
leather.

Information was paraphrased from, and inspired by Wikipedia, Mobile Leather Service, and Contract Leathers.

 

Get to Know Your Hide

The Bend

Thickest and firmest part of the hide, it is 2-4 ounces thicker than the remaining hide.  Don't stretch this piece of leather too much, because it's not going to happen.  The bend molds best when tempered in warm water before any serious stretching happens

The Neck and The Middle

Most of the blemishes are found here, we call those nature-made characteristics! You may even end up seeing some of the fat wrinkles left even after the tanner finishes up with these pieces.  The Middle stands alone in having the most tensile strength.  It is can do almost anything The Bend can, especially when products require more length

The Belly

This particular piece is softer and looser.  Many refer to is as "The Waste", but usually it is added to other types of leather in the production process.

Featured above is a diagram taken from the Famous Horween Leathers' website.  It is the most intricate depiction of the Bovine Hide. 

 

Tanning Methods

Vegetable Tanning

"Vegetable tanning uses tannin. The tannins (a class of polyphenol astringent chemical) occur naturally in the bark and leaves of many plants. Tannins bind to the collagen proteins in the hide and coat them causing them to become less water-soluble, and more resistant to bacterial attack. The process also causes the hide to become more flexible. Hides are stretched on frames and immersed for several weeks in vats of increasing concentrations of tannin. Vegetable tanned hide is flexible and is used for luggage and furniture." 

Leather Vegetable Tanning Vegetable tanning is an artisan tradition that the tanneries associated to the Genuine Italian Vegetable-Tanned Leather Consortium have handed down from father to son for over 200 years, using both antique recipes and state-of-the-art technology. http://www.pellealvegetale.it/en/skin/vegetable_tanning-13.htm Video by Oliviero Toscani Editing by Marcella Pastore http://olivierotoscanistudio.com/

- Wikipedia

Mineral Tanning

"Prior to the introduction of the basic chromium species in tanning, several steps are required to produce a tannable hide. These steps include: Scudding (removing the hair), Liming (the introduction of alkali agents such as sodium hydroxide), Deliming (restoring neutral pH), Bating (softening the skin with enzymes), and Pickling (lowering pH of the hide with salt and sulfuric acid). The pH is very acidic when the chromium is introduced to ensure that the chromium complexes are small enough to fit in between the fibers and residues of the collagen. Once the desired level of penetration of chrome into the substance is achieved,the pH of the material is raised again to facilitate the process. This step is known as "basification". In the raw state chrome tanned skins are blue and therefore referred to as "wet blue." Chrome tanning is faster than vegetable tanning (less than a day for this part of the process) and produces a stretchable leather which is excellent for use in handbags and garments."

-Wikipedia

Chromexcel

"Chromexcel is the original pull-up leather; using time honored techniques and formulas that were developed nearly 100 years ago.  Chromexcel is still produced in the United States using a bark retannage from a proprietary recipe, and then genuine hot stuffed with our secret blend of natural oils and greases.

Chromexcel is characterized by a rich pull-up in full aniline, hand rubbed finishes.  Made to this day with old world craftsmanship, modern Chromexcel carries on a long history of superior comfort and durability."

- Famous Horween Leathers