Leather
The modern leather armchair was reportedly inspired by an 18th-century English noble who wanted a suitable seat to lounge in during billiard games. Whether or not an aristocrat's whim really gave rise to the easy chair, it is true that the best leather-upholstered furniture made today still relies on techniques developed in 18th-century Europe.

First a frame is constructed, usually from a cured hardwood that will lend strength to the structure. Most frames are assembled using mortise-and-tenon joints, in which wood is fitted together using square pegs and sockets. This is the strongest type of joint.

To create the foundation of the seat, the frame is covered with webbing woven from hard-wearing natural fibers. Next, the upholsterer affixes springs to the frame with elastic tapes or rope. Springs act like a car's suspension system, providing even support for the seat. In well-constructed chairs, each spring may be secured by as many as eight hand-tied knots.

Layers of padding are placed over the springs, and finally, the padding is covered with leather. The best upholstery usually features aniline cowhide or lambskin. Aniline leather is a soft, high-grade leather that is vegetable-tanned and then dyed using plant-derived substances-methods that highlight leather's natural appeal.

Vegetable tanning preserves animal hides by soaking them in the tannins from tree bark. This technique produces more supple leather than mineral or chemical tanning, and helps leather stay durable, but also become softer with age.

Following tanning, color is applied to the leather by staining it with vegetable dye. Plant-based dyes are absorbed better into the leather and produce richer color than synthetic dyes.

The dyeing process for aniline leather purposely doesn't conceal the leather's grain or color variations and small scars on the skin. An overall natural look and feel is a hallmark of aniline leather. In keeping with that, minimal finishing is used. Some leathers are coated with a polyurethane finish, while wax is simply applied to the aniline leather to protect the surface. This allows the leather to acquire a unique patina over the years.