The most confusing term used within the leather industry is the term 'top grain.' Ironically, 'top grain' is the definition generally used when the grain is not genuine; when in fact the real grain has been taken away and an imitation grain has been embossed into the leather. When the genuine grain remains, the leather is call 'Full Grain' or 'Full Top Grain.'
The better quality of a hide or skin, the less it has to be treated. In a premium quality hide, the full natural grain is retained and exposed. One should see the "fat wrinkles" and natural markings, and the feel or hand should be supple and natural to the touch.
Although calfskins are finer than the hides of older animals, they are equal in durability and abrasin resistance because the fiber structure of the calfskin is denser, tighter and stronger than that of a cowhide. While some disparity of opinion exists over the relative quality of European hides vs. American hides, everyone generally agrees that hides in descending order of quality are: calfskin, premium cowhide, premium suede, select cowhide and production run cowhide.
Transforming hides into leather is done in three basic phases: pretanning, tanning and finishing. Whatever is done to a piece of leather after it is tanned is part of the finishing process. This may include: dyeing, rolling, pressing, spraying, plasticizing, lacquering, antinquing, waxing, buffing, embossing, glazing, waterproofing, stain proofing, flame proofing or any other post-tanning treatment. Full-grain leathers are color-treated only by transparent aniline vegetable dyes which shade or color the skins without concelaing or obscuring natural markings or grain character. Most furniture leathers have been treated with a costing of pigmentation to help even out the color or make the article more uniform and consistent.
Although many finish applications are administered for purposes other than altering or masking the surface of the leather, all applied opaque finishes and airtight surface sealants should be held suspect. Genuine, natural, unpigmented leather will breathe and ventilate, thus wicking away body heat. If upholstery leather is able to breathe, it can absorb moisture, be nourished, and remain soft and pliable. If the surface of the leather has pigmented or treated with many other finishes, as is the case for most automobile upholstery, the leather cannot breathe and may become stiffer.
The below diagram provides a general overview of the tanning lifecycle process. Please refer to the Glossary for details of each step.