The easiest way to categorize different leathers is by their tannage. So let's talk through some of the common types of leather we use to make our goods here at Outlander Supply Company.
Leather is a product made from animal skin. We should be immensely appreciative of its origin and respectful in its use. We mustn't forget where this material comes from and avoid waste. When animal skins are dried, they become rawhide, which is exceptionally stiff and pretty much unusable for any of the applications we would have in mind. The process of converting rawhide into leather is known as "tanning." Tanning a hide prevents bacterial decay and stabilizes its molecular structure.
Vegetable tanning is a natural process that dates back thousands of years throughout most (if not all) of recorded history. It relies heavily on tannins from trees (hence "vegetable") and water. It is a complicated and lengthy process that can take months to complete. Many practicing tanneries around the world boast a proprietary mix of tannins, and often these mixtures are strictly guarded secrets passed down through generations of tanners.
Vegetable-tanned leather can last a lifetime when taken care of properly. Like all leather, it is susceptible to dry rot and will require the occasional rub of leather balm. Vegetable-tanned leather also has the characteristic of acquiring a unique patina with use. It becomes darker in areas that absorb moisture or burnish and become small rubs. Many people enjoy this patina on their leather products as it makes it uniquely theirs, and is not reproducible on a "new" item.
In general, it can be challenging to achieve bright and vibrant colors using this tanning method, so most of the time, vegetable-tanned leather is found in varying shades of earth tones. Which makes sense given the tree tannins are likely brown, tan, or green.
By comparison, Chromium (chrome) tanning is a newer method for tanning leather. It was first done in 1858 by Friedrich Knapp from Germany and Hylten Cavalin from Sweden. However, it was an American, a chemist named Augustus Schultz, that would receive the first patent for the process. It relies on a mixture of chromium salts and tanning liquors that require constant and close attention as they can be environmentally harmful. It is a faster and more efficient process taking as little as two weeks to tan a hide (compared to the months for vegetable tanning).
Chrome tanned leather makes up the vast majority of leather on the market today. Lacking a real measurement, some speculate that as much as 90% of leather sold is chrome tanned.
There are benefits to chrome-tanning leather, including an amount of inherent water resistance in the finished product. By contrast, this is a much more difficult property to achieve through vegetable tanning. As well the chrome tanning process lends itself to producing a much more comprehensive array of colors than vegetable tanning, including vibrant pinks and teals. This ability to produce more colors has made chrome tanned leather popular in the fashion industry.
Latigo is not a tannage; it is a combination of tannings. Latigo leather is usually chrome tanned first and then re-tanned using a vegetable tanning process. In general, the hides that undergo this process become softer during the original chrome tanning and regain some of their rigidity during the second vegetable tanning.
This type of combination tanning is generally favored for heavier/thicker leathers used for saddlery and tack. It's also a good bit more expensive than either of the above tannages because it requires the overhead of both.