Sunday, June 7, 2009

From Abattoir to Atomizer Part I

Interpreting the Scent of Leather
Part I

Perfumes based on the “scent of leather” are far from being a new concept, and one can easily locate blogs and articles about the efforts of various companies and perfumers since the beginning of the twentieth century who have executed this idea, sometimes quite successfully.

Prior to taking on the project of creating a leather concept perfume of my own design, I tasked myself to learn about the historical process of leather making. My thought was that it would be better to be informed by the source material, rather than to just “copy” ideas of previous perfumers without any understanding of how those ideas were derived.

Part I of this article is a summary of my findings, in a roughly chronological order. Part II will be more about how the findings relate to perfuming and to fragrance interpretation.

An Ancient Epiphany

At some point long ago, our early ancestors discovered that by immersing animal skins in a brew of water containing various barks, berries, and leaves, the skins became rot resistant and significantly softer than dried skins. The active components of those liquids are now understood to be tannins, thus the process is now referred to as leather tanning.

The process of leather tanning spread rapidly and was improved upon by different nations. By the middle ages, tanneries were established in areas with adequate sources of all necessary materials such as water supply, a lot of trees rich in tannins, and a supply of skin and hides.

Tanneries at Fez

In ancient history, tanning was considered a noxious or "odiferous trade" and relegated to the outskirts of town, amongst the poor. Indeed, tanning by ancient methods produces such foul smells that tanneries are still isolated from those towns today where the old methods are used.

Skins typically arrived at the tannery dried stiff and dirty with soil and gore. First, the ancient tanners would soak the skins in water to clean and soften them. Then they would pound and scour the skin to remove any remaining flesh and fat. Next, the tanner needed to remove the hair fibers from the skin. This was done by soaking the skin in urine, painting it with an alkaline lime mixture, or simply letting the skin putrefy for several months then dipping it in a salt solution.

After the hair fibers were loosened, the tanners scraped them off with a knife. Once the hair was removed, the tanners would bate the material by pounding dung into the skin or soaking the skin in a solution of animal brains. Among the kinds of dung commonly used was that of dogs or pigeons. Sometimes the dung was mixed with water in a large vat, and the prepared skins were kneaded in the dung water until they became supple, but not too soft. The ancient tanner might use his bare feet to knead the skins in the dung water, and the kneading could last two or three hours.
It was this combination of urine, animal feces and decaying flesh that made ancient tanneries so odiferous.

Children employed as dung gatherers were a common sight in ancient cities. Also common were "piss-pots" located on street corners, where human urine could be collected for use in tanneries or by washerwomen. In some variations of the process, cedar oil, alum or tannin was applied to the skin as a tanning agent. As the skin was stretched, it would lose moisture and absorb the agent.

Spanish Cordwain (Cordovan) Leather

Fragment of Cordwain

The Caliphate of Córdoba (Arabic: خلافة قرطبة Khilāfat Qurṭuba) ruled the Iberian peninsula (Al-Andalus) and North Africa from the city of Córdoba, from 929 to 1031. This period was characterized by remarkable success in trade and culture; many of the masterpieces of Islamic Iberia were constructed in this period, including the famous Great Mosque of Córdoba. In January of 929, Abd-ar-Rahman III proclaimed himself Caliph (in place of his original title Emir of Córdoba) The rule of the Caliphate is known as the heyday of Muslim presence in the Iberian peninsula.

As part of the Muslim influence in Spain in the ninth century, embossed leather tapestries known as guadameci became favored by the church and among the elite classes. This style spread throughout Europe and beautifully worked Spanish Leather was used for wall covering and flooring in luxurious rooms, as book coverings, and as artistic upholstery and altar fronts in Italy, France and Spain.

Embossed gilded leather hangings in a Dutch interior, ca 1730, painted by Philip van Dijk

Russian Leather, or Russia Red Leather

Russia leather is a type of vegetable tanned leather, but has very distinctive oils used during the currying process. This oil has an aromatic scent, and because of this the leather has certain scent properties that also imparted insect resistance and mold and mildew resistance. This type of leather was used both ornamentally and functionally in book bindings and hat sweat bands. It was embossed with a pattern in the grain surface of the leather, such as a diamond pattern as well as others. The leather is known for its distinctive red color, but was also dyed black. This leather is no longer tanned.

In the making of this leather, the preliminary operations of soaking, unhairing, and fleshing were done in the usual manner, and then the hides were permitted to ferment and swell in a mixture of rye flour, oat flour, yeast, salt and water. The tanning process was then completed by putting them into tanning liquor composed of pine and willow barks, equal parts.

The currier would then temper the hides by impregnated them with a compound consisting of 2/3 parts birch oil and 1/3 parts seal oil. The leather was then "set out," "whitened," and well boarded and dried before dyeing.

A decoction of sandalwood, alone or mixed with cochineal, was used for producing the Russian red color, and this dye liquor was applied several times, allowing each application to dry before applying the following one. A brush was used to spread the dye liquor on the grain side.

The dye liquor was prepared by boiling eighteen ounces of sandalwood in thirteen pints of water for one hour, filtering, and dissolving in the filtering fluid one ounce of prepared tartar and soda, which was then given an hour's boiling and set aside for a few days before use.

After dyeing, the leather was again impregnated with the mixture of birch and seal oils (applied to the grain side on a piece of flannel) and when the dyed leather had dried, a thin smear of gum-dragon mucilage was given to the dyed side to protect the color from fading, while the flesh side was smeared with bark-tan juice and the dyed leather then grained for market.

"Boots of Spanish Leather" by Bob Dylan

Part II of this article to follow...

Acknowledgements to the following:
Henley's Twentieth Century Formulas Recipes Processes by Norman W. Henley and others

No comments:

Post a Comment