Here could be mentioned such old methods of leather manufacturing:

1. May be one of oldest: a skin of killed animal was painted by mixture of fats and brain of the same animal and softened flexing by hands - oil tanning

2. In India about 3000 years BC: tanning by the use of leaves and branches of plants – vegetable tanning.

In Bible is mentioned “skins were left to dry under sun and afterwards treated by “juice” of plants” – vegetable tanning as well.

3. In India BC: tannin by alum.

4. Very old: smoking over fire smoke – formaldehyde tanning.

5. North nations used such method: skins were soaked in urine and softened by chewing – urea tanning.

And interesting facts https://www.mikeredwood.com/leather-technology-background/timeline-for-the-leather-industry/

Hi,

I have teached History of Leather Tannin Technology and it is amazing how many diferent vegetable tanins and other materials like animal brains and livers were used to prepare/cure/transform skin.

For example, here is a recipe for Brain Leather:

“Brain tanning involves stretching and working the raw hide into a usable and stable state as opposed to the chemical baths and soaking that modern hides undergo during the tanning process. Step One – The fresh hide (not one that has begun the process of decomposition) is soaked in water for a number of days; the water is changed regularly and the hide kept completely submerged at all times. Rocks can be used to weigh down the hide and ensure complete submergence. Step Two – After the soaking of the hide in water has resulted in the hair being easily removed; the hair is “slipped” or removed, and the fleshing may begin. Step Three – The water is wrung out of the hide and the remaining flesh, fat and hair is stripped from the hide. It is also at this point that the hide is worked to a consistent thickness and overall uniformity. The hide is put on a stretching frame. Step Four: Putting the “brain” in brain tanning – The brains of the deceased animal is mixed with a little warm water and mashed into a paste. The brain mixture is applied to the hide until the hide is soaked through. Step Five – The hide is removed from the frame, washed in water again and wrung out. The rinsed hide is reattached to the frame. Step Six – At this point the hide is “broken”, or stretched, by various means in an effort to create leather which is supple, soft and even. Step Seven – The hide is coloured and preserved by being smoked. The hide is tented over hot coals covered in wet oak chips or corn cobs and smoked till dry and brown.”

The Arabs also produced leather by

“The skins are first put into flour and salt for three days and are cleaned of all fats and impurities of the inside. The stalks of the Chulga plant being pounded between large stones are then put into the water and applied to the inner side of the skin for one day. The hair having fallen off the skin is left for two or three days and the process is completed”

Em GRANTZ, Gerald J. (1985). Home Book of Taxidermy and Tanning.

The Hebrews were the 1st to discover the value of tanning with oak bark.

In Europe/Spain, the tanners were organized in Guildas, with very strict rules how to produce certain types of leathers and decorative items, such as Guadamecil.

Russian leather used Salix arenaria; in Siberia was bark of Betula or Abies spp.

The American Indians used a mix of brain and smoke to prepare their buckshin. But additionally decorated their shoes with colours from plants, wich gave them an extra tanner feature (one of them was Yucca filamentosa, but I have a bigger list).

Another brain recipe is:

“Brains contain emulsified oils, which permeate the water that they are mixed with, rather than separating from it. This quality allows the tanner to coat the fibers with lubricating oils, without saturating every pour of the skin with oil. Nearly all tribes used brains, although there were a few notable exceptions. Tribes of the southern Colorado River region used saguaro cactus seeds. The Tonto Apache used jojoba berries, a plant renowned for its emulsified oils. Sometimes, tribes in the southeast used sweetcorn. Peoples from the Gulf of Georgia used fish and sea mammal oils, with a somewhat different methodology. They would completely saturate the skin repeatedly with oils and then they’d degrease it with urine. This would chemically create a different type of leather, known as oil-tan. This is paralleled in modern days, by the tanneries that use cod oil to saturate the skin and then degrease it with sodium carbonate, resulting in what is popularly known as chamois. Other substances were put directly into the soak solution with the brains. Some of these, added oils; possibly to improve the feel of the finished skin, or at the least, to help the brains go farther. Other additives may have improved penetration by helping the brains slip past or break down the protective mucus. ADDITIVES TO BRAIN SOLUTIONS: Oils: spinal fluid, liver, bone marrow, tallows and fats, fish oils, acorn soup, pine nuts. Soaps: soaproot lather (amole lilly), yucca. Tannins: decayed wood (mostly fir), wild rhubarb, others. Ashes, corn meal.”

by: Whitney Bai

Mink oils have also been used du to palmitoleic acid . This includes macadamia nut oil (Macadamia integrifolia) and sea buckthorn oil (Hippophae rhamnoides), both of which contain a larger percentage of palmitoleic acid (22 and 40% respectively) than does mink oil (17%).

Hope this helps your work.

Best, Leonor

Dear Mr. Virgilijus & Ms. Leonor,

Both of your inputs are very valuable. I appreciate for your time and efferent taken to share your inputs. Thanks your both.

Is there any brand or any organisation working on implementing the natural leather tanning process(even if by containerizing) in a commercial level. How fare this is possible? Anybody kindly advice. Thanks in advance.

Dear Mr. Vinoth Azhagesan,

I do not know if I understood your question... Are you asking if there is an industry making vegetable tanned leather? If so, the answer is yes, in Portugal (Alcanena area) there are at least 2 leather factories that do produce vegetable tanned leather. I usually require their services for leather to be used in books conservation and restoration.

Dear Ms. Leonor,

Thanks for your message. You understood my question very well. I am glad that you know the factories working on vegetable tanning. I am more interested in understanding how this tanning process come commercially(large scale production) successful. It will be a great help if you can please advice the name and address or web-sight of those Leather factories? Your inputs are very valuable and interesting. Thanks you once again.

Dear Mr. Vinoth,

The contacts that I have of vegetable leather tanneries in Portugal are these:

- Curtumes - João B. Salgueiro, Lda., www.salgueiros.com.pt, Tel/Fax: 249 881 999. Vale de Oliveira, GOUCHARIA, 2380-162 Alcanena, Portugal. Secretary D. Hermínia Ramos email: [email protected]

- Lusitaniapel, Comércio e Indústria de Couros e Peles, Lda., Fábrica: Gouxaria - 2380-167 Alcanena, Portugal. Tel.249891988, Fax 249882446 / Armazém: Rua Maria 50C, 1170-212 Lisboa (Anjos), Tel.218146695, Fax 218121211.

Portuguese international phone link is 00351.

They are family businesses. Sometimes both take quite a long time (very long time) to reply. I do not know why. Keep on trying, but if they do not reply, I might ask someone else I know that might help.

Best regards.

Leonor

Dear Ms. Leonor,

Thanks for your contentious support and advice.