60 x 22 x 46cm large size
Sabtu, 14 Januari 2012
Classic n Vintages
60 x 22 x 46cm large size
Jumat, 13 Januari 2012
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Leather
Leather types
In general, leather is sold in four forms:• Full-grain leather refers to the upper section of a hide that previously contained the epidermis and hair, but were removed from the hide/skin. Full-grain refers to hides that have not been sanded, buffed, or snuffed (as opposed to top-grain or corrected leather) in order to remove imperfections (or natural marks) on the surface of the hide. The grain remains in its natural state allowing the best fiber strength and durability. The natural grain also has natural breathability, resulting in less moisture from prolonged contact. Rather than wearing out, it will develop a natural patina over time, with some cracking and splitting. The finest leather furniture and footwear are made from full-grain leather. For these reasons, only the best raw hide is used to create full-grain leather. One way to test if leather is full-grain is to lightly scratch its surface with your nail. If it leaves a lighter-colored streak, it's full-grain. Full-grain leathers are typically available in two finish types: aniline and semi-aniline.
• Top-grain leather is a misnomer: it gives the false impression that it is "top" quality. In fact, full-grain is the highest quality. Top-grain leather is the second-highest quality. Its surface has been sanded and refinished. As a result, it has a colder, plastic feel, less breathability, and will not develop a natural patina. However, it does have 2 advantages over full-grain leather: it is typically less expensive, and has greater resistance to stains.
• Corrected-grain leather is any leather that has had an artificial grain applied to its surface. The hides used to create corrected leather are of inferior quality that do not meet the high standards for use in creating vegetable-tanned or aniline leather. The imperfections are corrected and an artificial grain applied. Most corrected-grain leather is used to make pigmented leather as the solid pigment helps hide the corrections or imperfections. Corrected grain leathers can mainly be bought as two finish types: semi-aniline and pigmented.
• Split leather is leather created from the fibrous part of the hide left once the top-grain of the rawhide has been separated from the hide. During the splitting operation, the grain and drop split are separated. The drop split can be further split (thickness allowing) into a middle split and a flesh split. In very thick hides, the middle split can be separated into multiple layers until the thickness prevents further splitting. Split leather then has an artificial layer applied to the surface of the split and is embossed with a leather grain (Bycast leather). Splits are also used to create suede. The strongest suedes are usually made from grain splits (that have the grain completely removed) or from the flesh split that has been shaved to the correct thickness. Suede is "fuzzy" on both sides. Manufacturers use a variety of techniques to make suede from full-grain. For example, in one operation, leather finish is applied to one side of the suede, which is then pressed through rollers; these flatten and even out one side of the material, giving it the smooth appearance of full-grain. Latigo is one of the trade names for this product. A reversed suede is a grained leather that has been designed into the leather article with the grain facing away from the visible surface. It is not a true form of suede.
The International Union of Leather Technologists and Chemist Societies has a glossary of leather terms that can be found at IULTCS.
Other less-common leathers include:
• Buckskin or brained leather is a tanning process that uses animal brains or other fatty materials to alter the leather. The resulting supple, suede-like hide is usually smoked heavily to prevent it from rotting.
• Patent leather is leather that has been given a high-gloss finish. The original process was developed in Newark, New Jersey, by inventor Seth Boyden in 1818. Patent leather usually has a plastic coating.
• Shagreen is also known as stingray skin/leather. Applications used in furniture production date as far back as the art deco period. The word "shagreen" originates from France and is commonly confused with a shark skin and stingray skin combination.
• Vachetta leather is used in the trimmings of luggage and handbags, popularized by Louis Vuitton. The leather is left untreated and is therefore susceptible to water and stains. Sunlight will cause the natural leather to darken in shade, called a patina.
• Slink is leather made from the skin of unborn calves. It is particularly soft, and is valued for use in making gloves.
• Deerskin is one of the toughest leathers, partially due to adaptations to their thorny and thicket filled habitats. Deerskin has been prized in many societies including indigenous Americans. Most modern deer skin is no longer procured from the wild, with deer farms breeding the animals specifically for the purpose of their skins. Large quantities are still tanned from wild deer hides in historic tanning towns such as Gloversville and Johnstown in upstate New York. Deerskin is used in jackets and overcoats, professional sporting equipment for martial arts such as kendo and bogu, as well as high-quality personal accessories like handbags and wallets. It commands a high price due to its relative rarity and proven durability.
• Nubuck is top-grain cattle hide leather that has been sanded or buffed on the grain side, or outside, to give a slight nap of short protein fibers, producing a velvet-like surface.
There are two other descriptions of leather commonly used in specialty products, such as briefcases, wallets, and luggage.
• Belting leather is a full-grain leather that was originally used in driving pulley belts and other machinery. It is often found on the surface of briefcases, portfolios, and wallets, and can be identified by its thick, firm feel and smooth finish. Belting leather is the only kind of leather used in luxury products that can retain its shape without the need for a separate frame; it is generally a heavy-weight of full-grain, vegetable-tanned leather.
• Nappa leather, or Napa leather, is chrome-tanned and is extremely soft and supple and is commonly found in higher quality wallets, toiletry kits, and other personal leather goods.
The following are not 'true' leathers, but contain leather material. Depending on jurisdiction, they may still be labeled as "Genuine Leather."
• Bonded leather , or "reconstituted Leather", is not really a true leather but a man-made material. Some types of bonded leather are composed of 90% to 100% leather fibers (often scrap from leather tanneries or leather workshops) bonded together with latex binders to create a look and feel similar to that of 'true' leather at a fraction of the cost. This bonded leather is not as durable as other leathers, and is recommended for use only if the product will be used infrequently. An example for the use of this type of bonded leather is in Bible covers. The term "bonded leather" when used to describe upholstered furniture is a different product and construction. Bonded leather upholstery is a vinyl upholstery that contains about 17% leather fiber in its backing material. Hence, there is no leather in the surface of this product. The vinyl is stamped to give it a leather-like texture.Bonded leather upholstery is durable and its manufacturing process is more environmentally-friendly than leather production.
• Bycast leather is a split leather with a layer of polyurethane applied to the surface and then embossed. Bycast was originally made for the shoe industry and recently was adopted by the furniture industry. The original formula created by Bayer was strong, but expensive. Most of the Bycast used today is very strong and durable product. The result is a slightly stiffer product that is cheaper than top grain leather but has a much more consistent texture and is easier to clean and maintain.
The vast majority of leather is sold according to its area. The leather is placed through pin-wheel or electronic measuring machines and its surface area is determined. The unit of measurement is square meter, square decimeter or square foot. The thickness is also important, and this is measured using a thickness gauge (the unit of measurement is millimeters, e.g., 1.8 mm is a standard thickness for a school shoe).
In some parts of the world, top-grain thicknesses are described using weight units of ounces. Although the statement is in ounces only, it is an abbreviation of ounces per square foot. The thickness value can be obtained by the conversion: 1 oz/ft² = 1/64 inch (0.4 mm).
Hence, leather described as 7 to 8 oz is 7/64 to 8/64 inches (2.8 to 3.2 mm) thick. The weight is usually given as a range because the inherent variability of the material makes ensuring a precise thickness very difficult. Other leather manufacturers state the thickness directly in millimeters.
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