Sustainability in Leather Craft: How Cipriani Leather Champions Ethical Tanning Processes

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At Cipriani Leather, we take pride in transforming raw hides into luxurious leather using ethical and sustainable methods.

While we do not operate our own tannery, we collaborate exclusively with partner tanneries that employ green processes aligned with global standards for CO2 reduction, ethical practices, and the Green Deal—a commitment to a better future for humanity.

The tanning process transforms raw animal hides into durable leather, resistant to decay, and suitable for various applications.

This intricate procedure involves multiple chemical and mechanical steps to prepare, tan, and finish the material. Below is a comprehensive breakdown of the key stages:

Key Stages of Tanning Process

1.0 - Chemical Preparation in the Drum

All chemical operations take place in drums—cylindrical machines that rotate around their axes. These drums mix leathers, water, and chemical reagents according to precise algorithms, ensuring uniform processing. This stage sets the foundation for the transformation of hides into leather.

2.0 - Greening and Mortar Processes

Greening Process: This step involves relaxing the dermal tissue to enhance the skin’s absorption of tanning agents. The process often occurs alongside chemical treatments.
Mortar Process: The dermis is further treated to increase its pliability and remove unwanted components, such as fatty residues, through partial saponification. This step aids in preparing the hide for subsequent chemical interactions.

3.0 - Liming and Purging

Liming: The application of lime swells the skin, opening its fibers for easier penetration of chemicals.
Purging: Lime is removed by gradually lowering the pH to near the isoelectric point of collagen. Water is added, and sulfuric and hydrochloric acids complete the neutralization in a process called pickling. The dermis deflates and achieves a pH between 2.8 and 3, suitable for tanning.

4.0 - Tanning Phase

Tanning prevents organic degradation of the skin and imparts resistance to mechanical stress, temperature variations, moisture, and chemical agents. The most common tanning method involves chromium salts:

Chromium Tanning: Chromium salts bind to collagen fibers, increasing the leather’s stability and mechanical properties. Basification raises the pH to around 4, helping the chromium to fixate uniformly within the leather structure.
Specialized Treatment: Alligator skins, for instance, are stored on special racks for five days to allow proper chromium fixation.

5.0 - Wet Shaving and Synthetic Tanning

Wet Shaving: Skins are shaved to achieve uniform thickness (typically 1.1 to 1.5 cm) using rollers equipped with sharp blades.
Synthetic Tanning: This additional treatment whitens the leather, preparing it for vibrant coloration during dyeing.

6.0 - Drying Process

Standard Drying: The leather is dried on roundabout chains in ovens at approximately 30°C for half a day.
Special Drying: Skins from exotic animals (e.g., alligators, ostriches, and lizards) require specific drying techniques. For instance, snakes and lizards are stretched on slightly heated steel plates or glass surfaces, or dried naturally, depending on size and requirements.

7.0 - Selection and Dyeing

Selection: After drying, skins are sorted by size and quality in the crust warehouse and cataloged for customer orders.
Dyeing: Technicians use a pre-approved color master to match customer specifications. The dyeing process occurs in small drums for 3-4 hours, ensuring even coloration. Fatliquoring—the introduction of oils—is also conducted during this stage to enhance suppleness and durability.

8.0 - Final Drying

The final drying step ensures stability and avoids wrinkles. For exotic skins, clamps may be used to suspend and hold the leather taut. The drying process maintains a temperature of around 35°C in controlled environments.

9.0 - Finishing Process

The finishing stage enhances the leather’s aesthetic and functional qualities. This involves various treatments to improve softness, gloss, texture, and color. Key finishing techniques include:

Volanatura: Rotating the leather to soften its surface.
Dry Shaving: Refining thickness to meet customer specifications.
Spray Finishing: Automated spraying for standard items or manual spraying for bespoke products.
Rolling Finish: Passing the leather under rollers or brushes to achieve specific textures or reflections.
Polishing: Agate stones generate heat through friction, hardening casein layers and creating a glossy, mirror-like surface.

10.0 - Manual Enhancements

Hand Buffing: Deepens colors and enhances penetration into textured surfaces like scales.
Discoloration: Controlled washing creates vintage effects.
Painting: Customization with intricate designs or unique colors.

Through these meticulously orchestrated steps, raw hides are transformed into luxurious, high-quality leather suitable for diverse applications. Each phase is optimized to ensure minimal waste and maximum efficiency, reflecting a harmonious blend of tradition, modern technology, and our unwavering commitment to sustainability.