When you hear people talking about leather, you often hear the terms tanning, patina, and Napa leather. In this article, we will clarify these terms.
The Process of Tanning
The art of tanning leather is complicated and there are different layers involved. The material is split with the layer containing the hair on the top and the under layer beneath. The layer on top is referred to as full grain and elements such as sun and air give it the softness and strength required for a fine product. There are five stages in the process to tan the material including pre-tanning, tanning, selecting, dressing, and finishing. The hide is first soaked in revolving drums to extrude the salt. Liming is used to remove the epidermis and hair with calcium hydroxide. The material becomes more flexible and softer when sodium sulfide is used. The material is then split to ensure the smoothness of the top layer.
Tanning is what turns the hide into leather. This is done with mineral based salts to quickly penetrate the hide in one or two days. The hide becomes blue with a soft and fine finish. Once the tanning is complete the water is removed and the hide is graded according to quality with Nubuck and Aniline considered the best. The hide is then shaved, dyed, modified, and dried on a frame. Any rough edges are removed before the final finishing process. Blemishes are minimized and a protective surface is applied to ensure the product can be cleaned.
The Natural Patina
The highest quality of leather has a natural patina it acquires with age, sunlight, heat, water, moisture, dust, dirt, and the oils from the body. It requires care including being wiped down, conditioned, and carefully stored. If the hide has been painted it will not develop a patina. Products made from a full-grain will have the best patina including cow, alligator, and ostrich hides. Using your product naturally will provide the best results although patience is a necessity. The more the item is handled the faster the process will occur and the beauty and value will increase.
The Attributes of Napa Leather
Napa leather is characterized by softness, smoothness, can come from any type of animal skin, and is referred to as Aniline. It is considered precious, expensive, and flawless although it has a great sensitivity to insect bites, dirt, bleaching out, and scratches. This is because the pores of the hide have not been sealed and it has been dyed with colors that are water soluble. The grained side has been sanded resulting in an extremely smooth surface causing an even more pronounced appearance to the natural features of the hide. Napa leather is permeable by both vapor and water so the heat exchange is excellent. When the hide has been pigmented a binding agent is used so the color can be properly applied. Although this makes the hide less breathable it also makes it much easier to clean.
CP Slippers are made with hand-chosen and crafted Napa leather.
Be sure and return to learn more leather terms, uses, and processes in our continuing story about the History of Leather. Did you know that “Genuine Leather” is the lowest quality of leather? In our next instalment, we will discuss the difference in the three “qualities” of leather, Full-Grain, Top-Grain, and Genuine Leather.