Leather is a natural product. It comes from animal skins which have been chemically processed (tanned) to preserve them. A properly tanned hide (or skin) creates strong, flexible leather, resistant to decay.
Most leather is tanned cow hide. Cow hides are about 1/4 to 3/8 inches thick, which is too heavy for general upholstery application. Therefore, hides are split laterally, rendering an upper and lower cut.
The upper portion is the top-grain, or full-grain. The lower portion is the split. This cutting process creates different “faces” to the leather. The outside face of the top-grain or full-grain shows the natural grain characteristics, but is otherwise smooth; whereas, the underside appears as suede.
Finished vs. Unfinished
There are two basic categories of leather: Finished or Unfinished.
Finished leather is first dyed via immersion in an aniline dye solution, and then the outside face of the hide is coated with a pigmented resin, and then a subsequent clear-coating. Unfinished leather processing stops at the first dyeing process, without any resin coating. Finished leather is protected by the color-coating and clear-coating, and unfinished is unprotected, not having either of these subsequent coatings applied.
To further define the differences, finished leather color is from a pigment coating on the leather, whereas unfinished is from a dye in the leather. Finished leather is stain and fade resistant but lacks deep richness in color, and tends to be stiffer.
Unfinished leather tends to be more expensive. Note that the topical coating can range from thin to thick. If there is a very light color or clear coat on top of aniline-dyed leather, it is often referred to as “semi-aniline.” Semi-aniline leather offers modest protection while retaining much of the aesthetic beauty of an unfinished aniline-dyed leather.
Finished: The leather has a topical pigment coat applied. One of the most common coatings consists of a soft acrylic color coating under a urethane clear coating (for durability). These resins create a film that bonds to the surface of the leather. It’s primary goal is to protect the leather, providing wear, stain, and fade resistance. Finished leather will resist staining by water – or oil-based agents (if a drop of water is put directly on the leather surface, the water bead remains on the surface, and does not soak in and darken the material.) The clear coating mentioned above determines the final reflective value of the leather surface (ranging from high gloss, all the way down to a matte or dull finish, depending how much dulling agent is added to the clear coat resin before application), so sheen is not necessarily a help in determining leather type. Generally, finished leathers do not have that “buttery soft” leather feel (or hand) associated with raw leather. Also note, finished leathers can be described as aniline-dyed, and still have a topical pigment applied. Finished leathers are much less susceptible to fading.
Unfinished: The leather does not have a topical pigment applied, or it has a minimal resin coating to retain the hand of raw leather. The color is achieved by immersing hides in aniline dyes that are absorbed into the leather, accentuating the natural beauty of the hide. Because leather’s absorption characteristics are not uniform, variations in color are common. The water drop test will result in the drop transferring into the leather, darkening or staining the area. Because unfinished leathers are colored using organic aniline dyes, they are much more susceptible to fading (caused by UV exposure).
|Finished (coated)||Unfinished (raw)|
|Top-Grain or Full Grain||Top-grain aniline-dyed (no coating)|
|Corrected Top-grain||Pull-up, waxed (distressed)|
FEATURES OF DIFFERENT FINISHES
|Finished (coated)||Unfinished (raw)|
|Stain Protection||Color coating protects against staining||Absorbs liquid – prone to staining|
|Fading||Pigment coating is fade resistant||Dyes fade from light exposure (UV)|
|Color Richness||Color coating is flat, lacking depth||Coloring is rich, accentuating natural beauty of the leather|
|Feel (or Hand)||Leather feels harder, colder, stiffer||Buttery soft, warms quickly, inviting|