From rawhide to leather - the story of a transformation

The pure raw material, the animal skin, is initially an easily perishable, organic product. Only through processing the raw material becomes a resistant and durable end product that can be processed into an accessory, such as a bag, into clothing, such as a jacket, or into an object of furniture, such as the sofa. This transformation requires a complex manufacturing process, which - depending on the type of leather and the tanning process - takes several weeks to months.

Raw material

The most common type of leather is bovine, but the leather can come from almost any animal, such as crocodile, sheep, python, pigs, and others. Most hides come from factories that produce meat for consumption, so every animal part is used to serve multiple purposes—the art of leather processing results in products that last for decades.

The leather of the highest quality can only come from an animal whose quality of life has been raised. This means that the animal has not been fed hormones or growth substances, has not been kept near electric fences or barbed wire, and has not been neglected from a hygienic point of view. Although insect bites, scars, and other signs produced in the animal's life are a sign that the leather is natural, they must not be too deep or too many. 

The skin must be removed from the animal immediately after it has been slaughtered to avoid the skin drying out - this step can be done manually or automatically. The result is a white surface that needs to be treated with salt or brine to avoid decomposing. Before starting the process, the leather is soaked in water to remove the dirt and salts that helped preserve it.

To remove hair from the skin, a chemical solution containing calcium oxide is used - this step is also called a lime bath and softens the skin. It can last 1-2 days and removes dead cells from the surface. This step can also be done without chemicals.

After bathing and soaking, the leather will be moistened, and its thickness will increase by approximately 4 mm. At this point, the leather can be separated for different products. For example, the upper part of the split, which has a much tighter fibre structure and provides resistance, will become full-grain leather used to create products of better quality. Treated correctly and carefully, this layer produces a supple, durable leather with a perfect patina.

Tanning

The tanning process transforms hides into leather by preserving the material and stopping decomposition. During tanning, the organic raw material is transformed into durable leather. Through tanning, the animal skin is preserved in the long term by the tanning agents forming a chemical bond with the skin fibres. This step occurs in a special tanning drum and a special tanning solution. Tanning agents can be of several types:

• Chrome tanning - It has been the most common tanning method since 1900 and is made with harmless chromium (III) salts, giving the skin a bluish-grey colour. 
• Vegetable tanning - Tanning with oak or spruce bark, quebracho wood, tara pods, olive leaves, rhubarb roots, or mimosa bark offers a brownish colouring. Although this method is 5000 years old, today is used in only about 10 percent of global production.
• Alum tanning - Tanning with aluminium salts is delicate and gives the colour white.
• Synthetic tanning - Tanning is done with artificially produced substances such as formaldehyde, glutaraldehyde, phenols, and acrylates, and it is often used in combination with chrome tanning or vegetable tanning.

After the leather is tanned, next comes liquoring, the stage in which special fats are added to the surface of the leather to help it be stronger and softer. Next comes the elimination of excess moisture by applying mechanical pressure, which is done with special machines in the form of rollers. After this drying process, the leather can be sorted according to quality: from those with imperfections to those without a flaw. The quality level of the leather will determine its use as well as the quality of the final product. The hides are then shaved to specific dimensions, and the resulting scraps can be used to create small leather goods such as bag accessories or wallets.

Re-tanning

In most cases, the leather must go through a tanning process again to prepare it for its intended purpose. Either the vegetable mixture or the chromium salts will be used again, and the excess moisture will be removed by pressure. After finishing the tanning process, the skins must be dried - several methods can be used, but the most well-known are air drying or vacuum drying.

During the re-tanning stage, an excellent base can be created for the next stage, the dyeing stage, by applying a bleaching agent to the surface of the leather.

Dyeing

The skin is coloured in a drum with the meticulous dye created with a computer program. The painting process can be long and repeated until the desired result is obtained. During painting, cuts are made to ensure that the paint has completely saturated the skin. When the final result is reached, any residual dyes or chemicals are removed by rinsing. The skin dries and prepares for the last touch-ups.

Finishing

This is the stage in which the skin will acquire suppleness, flexibility and a matte or glossy finish. For a high-quality finish, the leather is stretched with the help of special machines and softened with natural oils. And finally, the last step in the transformation is the finishing spray which, for example, can be made of acrylic to give the skin a lacquered look. Completing this step means putting the leather in an oven to be hardened.

Note: After drying, the leather can be stacked to prevent wrinkling. Full-grain leathers can only be ironed until the desired sheen is obtained.

As we see it in each product, the leather goes through multiple processing steps that must be strictly observed. Any deviation from the process can result in a lower quality leather that cracks, mould or discolour. LEONTHE handbags are created in a workshop in Italy that has the experience of 3 generations of artisans in processing the best quality leather. All the leathers used in making our office handbags for men and women have a traceability certificate that ensures their quality. Discover now the 2022/23 limited collection.