May 29, 2014 by Ville Raivio
“Genuine leather” has not been a useful marking in decades. Leather can be made from most any animal, and it ranges in quality from beat-up poor to illustrious, so the marking of does not serve the buyer much at all. Each animal and hide is an individual, thus leathers will have clear distinctions from the start. These will only grow stronger with the chosen tanning method and handler, making the skill of spotting quality in leather useful for any man. Thanks to swell durability, adaptability and ease of use, leather is unsurpassed in manifold objects. The most common uses are belts, accessories, footwear, bags and furniture, but imagination alone is the obstacle. Even miracles are not ruled out, for any skilled cordwainer can make a flat hide bend to a 90-degree angle and stay put for years, as exampled by seamless Chelsea boots.
Tanning methods are several. Vegetable-tanned leather is tanned true to its name, with tannins derived from plant sources like bark and leaves, and this method is among the oldest still in use. A prime material among the Flora is the venerable oak, whose leaves and bark, combined with patience and time, yield some of the strongest leather known to man. Oak-bark tanned leather also has a pleasant smell, light colour and a high price tag. Most vegetable-tanned hides are light brown and spread wonderful aromas for the curious sniffer. These hides are fairly easy to craft into beautiful goods and the tanning process, while slow like the turn of seasons, is environmentally sound. Vegetable-tanned leather doesn’t enjoy moisture, though, and thinner leathers will bleed colour and turn unstable or brittle with time while the thickest hides, like leather sole bends, will only laugh the rain to scorn. Concerning apparel, vegetable hides are mostly used on soft moccasins, leather linings, gloves or inner and outer soles.
The vast majority of leather is chrome-tanned, a method born in 1858 when chromium sulfate was first used in tanning raw hides. This inorganic ion compound is highly effective and fast, producing flexible, moldable and moisture-resistant leather that keeps its colour. Drum-fresh chrome hides are blue due to this tanning agent and must be dyed before use. If the tannery practices shenanigans by not cleaning residue liquors, chrome tanning is highly unsound for the environment. While vegetable tanning takes from a few days to closer to one year, chrome hides will be ready in a day or two. The end result will look like the blue diva from The Fifth Element and reek like a Mangalore, but chrome leathers will age well and resist moisture so this leather is widely used in finer leather goods.
Vegetable and chrome tanning can also be combined. Then the process won’t take as long or reek as much, and the end result is a fairly swell union of the historical tannins and industrial chrome. Apart from these two, raw hides can also be tanned with formaldehyde, cow brains, oils, aldehyde, rose oil, synthetic tannins and aluminium salts, which all have their effect in the finished leather. The tanner may also take his cue from Native Americans, who crafted raw hides by scraping them thin, soaking them in lime and then stretching them between a few poles. This native leather is the least durable and most stiff, but also the easiest and cheapest. After one or several methods, the leather can also be treated with oils, waxes and tallow. Apart from colouring, different patterns can be pressed or carved onto the surface to change the result and form artistic visions or an artificial grain.
Manufacturers have ways to have their way with customers. Enter “Genuine Leather,” exeunt earnestness. All leather is leather, yes, but not all leather is worth buying. The poorest of these is called corrected grain leather, whose surface grain is sanded off to remove scars, blemishes, unevenness or stretch marks, then coated with a thin layer of plastic that creates an unnatural shine. These hides are taken from old and battered animals and chemical treatment is simply used to hide imperfections. All hides that won’t make the cut to become quality leather are corrected. This poor leather-like substance can be identified by its high shine, plasticky surface and pungent smell. Hair follicles can’t be seen at all for they’re sanded off and covered with a plastic film. When bent, corrected grain leather will form deep creases that cannot be prevented with shoe trees or one litre of Saphir. In due time, these will turn into crevices, to clefts, to chasms, until the leather breaks into a void.
The most common leathers are bovine. Calfskin is very durable, smooth, clean and long-lasting but expensive, while older cow hides are cheaper and good enough for many uses, and water buffalo is another very durable leather and spotted with bigger follicles than calf. Bovine hides are around three millimetres thick, and most will be split in the tannery as per the customers’ wishes. The thickest hides will be split into several parts and most shoe leathers measure a bit over one millimetre, glove leathers thinner still. Some thick leisure bags and work wear boots use unsplit leather for added beefiness, though most bags use leathers in the measure of two millimetres. Bovine leathers split into two parts become top-grain leather, the upper part with follicles, and split leather, the bottom part with the flesh side. This lower part retains but ~10% of the full hide’s original strength, making split leather always the poorer choice. It’s often pressed with machines to make an artificial grain on the upper side that once was the animal’s outer skin.
The fleshy side of split leather is usually cleaned by sanding, thus forming split suede. This material is less durable than suede made from the top-grain side, which is as fine and dandy as top-grain leather. The highest-quality shoe and clothing suede uses top-grain leather, either in the form of nubuck or reverse calf. Nubuck is the top surface that is lightly sanded to form a nubby texture that’s denser than suede, and reverse suede is the bottom surface that’s finished to form a uniform suede nap. All suedes gather more dirt and get more soiled than smooth leathers unless the nap is treated with protective coating, usually with a spray of sorts. Suede can also be cleaned with special products that make a world of difference. Thus the poor reputation of suede as a delicate, less durable material is an untrueism.
The upper part of a split hide, top-grain leather, is the better stuff. It still has the durable outer surface that used to house the animal’s hair. If this top-side has nicks, cuts, bruises or blemishes, these can be sanded down and finished with a top coat of dyes, which make the leather less cool and prevent a nice patina. As long as the treatment and dyes last, the coated leather shuns dirt and moisture better than aniline-dyed leather. Most of the better leather goods in stores, such as pricy bags and footwear, are made from more or less modified top-grain leather.
By far the finest leather type is aniline-dyed top-grain calf leather, which is never coated or sanded to hide natural marks. Only the finest hides justify the trouble of aniline dyes, which soak through the surface deep into the leather, preserving the grain, surface, texture and quirks of the leather. Most makers will click or cut away all spots with traces of the animal’s past life, leaving the best bits for the best uses. Follicles can be seen clearly as small dots and the strength and durability are much better than on splits. Aniline calf allows evaporation from the wearer’s skin, preventing hands or feet from getting gurgly and squishy inside gloves or shoes.
Instead of breaking down to crevices, top-grain leather develops patina after bending and with abrasion as the years pass by. Unfortunately not all tanners allow plenty of time for the hides to drink deep of the dyes, and leathers such as these are rush-jobs that lack depth. Aniline-dyed and rush-dyed leathers are difficult to differentiate for the layman, unless the leather goods show the sides or bottom surface of the hide. If either of these spots shows blue colour instead of the surface colour, the leather has been shoddily tanned. Trouble is, most hide corners are quickly coated to hide the blues below. Scratching the leather may show the truth, even if the reader can’t handle it.
After internalising all this, I hope the reader understands why “Genuine leather” is not a reliable marking. If the seller doesn’t know what’s for sale and the customer knows no better, what follows is commercial theatre — or cheating at its rudest. Before making a purchase, it can do no harm to inquire the seller if the goods have been made of aniline-dyed top-grain calfskin, that quality stuff with no peers. Vegetable and chrome tanned leathers, in turn, can be separated with a few handy tips. When the surface is scratched and these scratches can be hidden by brushing the surface with a cloth, the leather is tanned with vegetable tannins. Smell is another factor, as natural tannins are pleasing for the nose. Burning a small cut of the leather should also show what’s what: green ash is a sign of chrome.
Asking about the origin is helpful. At the moment, the finest raw hides are raised and tanned in Europe, where certificates and advanced technology yield quality. Better still to ask about the tannery, though this bit does demand knowledge about the differences between the many hundred makers in Europe alone. Perhaps the easiest route to fine results is to buy one’s leathery charms from reputable makers trading in leather goods. They must uphold a fine level in order to keep their reputation and client base gathered over decades or centuries of excellence. Specialty stores, whose retailers are in it for the passion as well as a bit of profit, can likely be depended on when leather is concerned. Corrected leather can be spotted by looks alone, but split and top coated leathers are more difficult to tell from aniline hides just with eyes. As long as there are buyers, there is a shyster for each of them — and the client usually gets what he pays for. Excellence in leather is an investment in time.
First published in Finnish 3.3.2013.