What is the technology behind leather tanning? The leather making process is one of the oldest technologies and started to be developed with the meat consume. There are different methods of preparing animal hides and skins for future utilization as leather. Tanning is the process of treating animal skins to produce leather – a durable and flexible material. Untreated skin would harden out and putrefy as it is an organic material making its utilization in the articles we wear not possible. The aim of the tanning process therefore is to prevent this from happening through modification of the protein called collagen. Tanning can be performed using either a vegetable method with plant polyphenols, mineral methods with metal salts (in particular chromium) and a metal-free method with synthetic tanning agents, aldehyde tannages and oligomers. (source: “Modern tanning chemistry” from Anthony D. Covington) The choice which method will be applied affects the final properties of the leather, human health and environment. The continuous shifting of leather industry and its growth to the east and south is justified with lower labor costs and less stringent environmental legislation. It is not just the matter of lax environmental law, rather its enforcement is the issue here. There is still a long way to go to make the people understand which price is paid by the nature and the workers of this industrial sector in the 3rd world countries. Chrome tanning The prevailing methods of leather tanning in the fashion industry are based on chrome-tanning. Indeed the products produced with vegetable tanned leather have very small market share. Chrome tanning (also known as mineral tanning) is the most popular from mineral-based methods. The tanning agent used in process is chromium sulfate. Chrome tanning was invented in 1858, which makes it one of the youngest methods and the most popular one by the industrial manufacturers. Chrome tanning is an effective method to produce a soft uniform leather in very fast way. The whole process takes about a day and this facts made this manufacturing method so popular and widespread in the leather industry. Sounds good, doesn’t it? That’s one of the reasons why about three quarters of all leather used in fashion industry is chrome tanned leather. But the advantages of chrome tanning have their price. First of all, the chrome tanning process is harmful for the environment and dangerous for the people working at tanneries or live nearby. As any heavy metal chrome is extremely toxic and have carcinogenic properties. As this method is easy and doesn’t demand high-qualified skills, many tanneries are situated in 3rd world countries in order to keep down the manufacturing costs. In many cases the working environment in this countries doesn’t provide protection to the workers and they are directly exposed to strong chemicals, having as consequence many diseases and a short life expectancy. There are no strong restrictions on the production, so all chemicals used in the tanning process just flow without being filtered into rivers. The damages to nature and people are severe, when the birth rate of healthy born children and life expectancy in the affected areas are as low as they are now. But developed countries are also affected by this destructive and careless approach and not just directly through utilization of such leather, but also through contaminated supply in the food chain. The leather waste from many manufacturing locations in the 3rd world countries is processed into flour which is sold to shrimp farms as food. This shrimps are contaminated with all this heavy minerals and are exported everywhere in the world landing in our dishes. Despite being publicly recognized for these significant downsides, chrome tanning is still the most used method in the fashion industry. Vegetable-tanning Vegetable-tanning is one of the oldest methods of making leather – it has been used for thousands of years. This process is completely chromium-free, so it doesn’t include any harmful chemicals. It is an old-world, artisanal technique that takes advantage from the tannic acids naturally found in some plant species, by using barks, branches, leaves and even some fruits applied in specific ways. These techniques require experienced and skilled workers and each tannery keeps its recipe and process secret. The skins keep its light rose-beige appearance before being painted and have its typical woody and earthy smell. There are some disadvantages of vegetable-tanned leather which need to be mentioned to be fair: Many steps in production process are still leaving its footprint on the environment, especially the ones performed before tanning Tanning requires high consumption of water, although the result is harmless opposed to the chrome and aldehyde methods Depending from the plant phenols used for the process the production time is long and vary between 3 weeks up to 2 month Long production times are causing high final cost But there are also awarding advantages unsurpassed by any other tanning methods: It doesn’t negatively affect a human health, especially important by the direct contact with the skin Such properties as high durability and strength provide this material a long life cycle Due to its bio-degradable properties it has low impact on the environment It has remarkable esthetics, with more vivid color appearance, more natural and organic look Its aging qualities, influenced by exposure to natural elements, nurture unique patina acquired after some time An almost completely forgotten valuable knowledge of an old craftsmanship was recently retrieved to provide an alternative material choice for the conscious consumer. This revival managed to revitalize the regions with traditional leather production and helped them to survive in the era of consumerism. So why choose vegetable-tanned leather goods? Because you will be doing a responsible choice and purchase a sustainable product, which will last, give you comfort and allow you to diminish your footprint on the environment.