The story of leather began many years ago, with the first chapter unfolding back in prehistoric times. The art of leather tanning is arguably one of the oldest human activities. It has evolved through the ages hand-in-hand with the skills and needs of mankind. Tanning is the process by which raw animal hides are turned into leather. The protein structures of the hides are permanently altered, preventing them from decomposing. The tanning process creates strong, flexible and long-lasting leather that can be put to use in a whole plethora of ways.
Here we’re exploring the fascinating history of leather tanning, from where it all began in the Old Stone Age, right up to the present day ...
Where the story began
Primitive man used animal hides to create clothing and shelter. However, the extreme conditions they were trying to protect themselves from often damaged the hides. Skins became stiff at low temperatures, but would rot in the heat. In attempts to create stronger, more flexible hides that could provide protection from the elements, the first basic tanning process was developed. This involved stretching the skins out on the ground to dry and then rubbing them with animal fats and brains.
The emergence of vegetable tanning
Around five thousand years later, the Ancient Egyptians are said to have invented plant-based tanning, using the bark of the gum Arabic tree. This was a slow process that made use of naturally-occurring tannins found in bark and plant leaves. Hides were stretched out on frames and immersed in vats containing concentrated amounts of tannin. Tannins bind to collagen proteins in the hide, causing them to become more durable, flexible and resistant to bacteria.
Before the hides were ready for this tanning process to begin, there were long and painstaking preparatory stages for ancient tanners to follow. These rather arduous processes, with their foul-smelling odours, gave ancient tanning a very unglamorous reputation. They were the reason that tanneries were almost always isolated from towns. Part of the preparatory process involved pounding the hides to remove excess fat and flesh – not the most pleasant of tasks! Afterwards, tanners loosened any hair follicles by leaving the hides to putrefy for months or by soaking them in vats of urine and then scudding the hides. Then, during the bating stage, tanners worked animal dung and brains into the hides to ferment the skin and make it suppler. In some tanneries, workers used their bare feet to knead the skins with the waste mixture, a process which could last two to three hours. Once these noxious stages were complete, the hides were ready for tanning.
Little did the Ancient Egyptians know, but vegetable tanning would be the dominant way of making leather until 1900. Other tanning methods were also used, including those based on sesame oil and the alum mineral, but these were not as popular.
Refining the tanning process
In the Middle Ages, the depilating action of quicklime was discovered, a technique which is still used today in many modern tanneries. This replaced the unsavoury ancient method of soaking hides in urine. During the preparatory stages of leather production, hides are soaked in an alkali solution. The main aims of this are to remove hair fibres and other keratinous matters, and to ensure that the collagen proteins are in a sufficient condition to allow satisfactory tannage.
The discovery of chrome tanning
The discovery of the tanning power of chrome salts in 19th century France proved truly revolutionary for the leather industry. It meant that the time required for tanning was drastically reduced from around one year to as little as one day.
The technique of chrome tanning (also known as mineral tanning) uses a solution of chemicals, acids and chrome salts to dye raw hides. First the hide is left in an acid salt mixture, before being placed into the chromium sulphate. In its raw state, a chrome-tanned skin is wet and tinged with blue, which is why it is sometimes called a ‘wet blue’. In this fresh state, wet blue is globally transportable, making it a highly sought-after material for global processing across international markets.
The process of chrome tanning is still commonly used today. In fact, it is the most popular kind of tanning in the global leather industry. Chrome-tanned leather is thinner and softer than vegetable-tanned leather, with a more fibrous nature. Despite being stronger than its vegetable-tanned counterpart, chrome-tanned leather weighs much less. These properties make it an ideal choice for clothing and upholstery.
Leather tanning of today
Whilst chrome tanning dominates the leather industry, the ancient craft of vegetable tanning is still practiced today, with modern-day leather artisans honouring the traditional techniques of craftspeople gone by. There have of course been some improvements to the process to make it more hygienic and efficient!
Here at Colville Leather we are fascinated by the history of leather tanning. It may be an art that stretches back for thousands of years, but many of the basic processes and tools remain almost unchanged. We believe this gives vegetable tanned leather goods an authentic charm that is hard to resist.
To see our full range of vegetable tanned leather products, including wallets, belts, bags and keychains, visit our website.