Before figuring out carved leather, vegetable tanned leather, tree extract leather, tannin extract leather and leather, first understand what leather is and what leather is. Untreated skins taken from animals are called "raw skins" or "raw skins", or simply "skins", which will rot in a short time. Leather is called "leather" when vegetable tanning agent (tannic acid) is extracted from plants or tanned with chemical agents such as metal chromium and synthetic tanning agent. After dyeing, oiling and drying, leather can maintain its quality and flexibility under moderate maintenance. Among them, the leather tanned by vegetable tanning agent (tannin acid) is very suitable for carving and leather molding because of its strong water absorption and high plasticity. Vegetable tanned leather is a kind of leather tanned with vegetable tanning agent, which contains no substances harmful to human body. It is a kind of green leather that can be used in direct contact with skin and is harmless to human body. Can be used for handbags, backpacks, saddles, insoles, shoes, hats, belts and other leather products that can be in direct contact with the human body. Vegetable tanned leather is mainly tanned with vegetable tanning agent. Vegetable tanning agents mainly use vegetable tanning materials and vegetable tannins, which are polyphenolic compounds such as tannins and plant polyphenols contained in plants that can turn hides into leather. Vegetable tanning materials are rich in tannin (tannin >: 8%), and the skins, stems, leaves, fruits, etc. which are valuable are called vegetable tanning materials. Among them, the solid block or powder obtained by extracting tannin from vegetable tanning materials with water is called tannin extract. Therefore, vegetable tanning leather tanned with vegetable tanning agents is also called tannin extract skin. Bark, wood, shells and leaves of plants are all tannin extract raw materials. Leather tanned by vegetable tanning materials, so some people commonly call it tree cream skin, and others write it as tree cake skin. The characteristics of vegetable tanning leather are: the tanned leather is soft and leathery, with compact fiber structure, small extensibility, good formability, plump and elastic board surface, no greasy feeling, shiny grain surface and suede surface, easy to soften when absorbing water, easy to reshape plasticity, and the color is from light flesh pink to light brown, which is most suitable for making leather. It can be classified into: sole leather (inner and outer soles), industrial leather, fitting leather, automobile seat cushion leather, luggage leather, belt leather (belt leather is often used by many netizens), and mat leather. Tanning methods of cowhide can be divided into-vegetable tanning--------------------------------------------------------------------------------- At present, it is no longer used in Europe and America, and the environment-friendly vegetable tanning agent is used for tanning leather. White tanning leather-similar to vegetable tanning, leather made of two or more processing agents is white, which is suitable for batik and colored leather production. If you want to have bright colors, This kind of leather is the most suitable. Japanese leather is made of this kind of leather. Three nouns -1. Tanning: the qualitative change process of transforming rawhide into leather is called tanning. 2. Tanning agent: the basic substance used to transform rawhide into leather is called tanning agent. 3. Tanning method: chrome tanning, aluminum tanning (white tanning) and vegetable tanning. By analogy, beginners are not easy to understand leather carving and how to buy leather, so they should be experienced. Before you start to choose leather carving materials, you must have correct leather knowledge. The ecological region, environment, sex and animal age of various animals are not the same, and there will be great differences after being made into leather. Generally speaking, there are good animal hairs in the frigid zone, but the fibers in the skin are very rough. Beavers and foxes are representatives. Temperate and tropical animals are the source of fine and soft leather. Even the skins obtained by the same animal in different seasons are different: insiders call them summer skins or winter skins. The most appropriate choice should be made according to the purpose of use. Carved leather for carving belongs to full-grain leather, and the leather suitable for dyeing and vegetable tanning is the best. Choose strong leather for shoulder, back and waist. Common defects of vegetable tanned leather: 1. The wrinkle between the wrinkle surface and the tube wrinkle surface is called the wrinkle surface, and the serious wrinkle surface is called the tube wrinkle; 2. There is a white mark on the surface of bare skin with white flowers that does not absorb tannin locally; 3. The defect caused by the incomplete penetration of raw tannin into the inner layer of the leather; 4. The crack surface bends the leather to a certain shape, resulting in cracks on the leather surface. 5. Dark spots appeared on the suede. Supplement: In 1978, the Federal Republic of Germany took the lead in the certification of green products. Many developed countries have followed suit. In September, 22, the European Union issued the directive 22/61/EC, which stipulated that AZO dyes (AZO) with the concentration of aromatic amines exceeding 3ppm should not be used in the production of textiles or leather products that may be in long-term contact with human skin or mouth. With the increasing concern of EU countries for the environment, the European Union has continuously issued new directives and banned some new chemicals, some of which will cause harm to human body, while others will. If the products of leather industry and textile industry are exported to Europe, they need to be consistent with EU directives at any time, and may be returned or even destroyed. The most suitable ones are the following natural vegetable tanned leather, including British vegetable tanned leather, Brazilian vegetable tanned leather, followed by domestic vegetable tanned leather, etc. The leather carving made by printing tools has a strong three-dimensional effect and clear patterns. Suitable for post-processing such as coloring. Brown vegetable tanned leather, also called tannin extract, is light tea to light brown in color. It is also leather for leather carving, and it is commonly used for scabbard and harness. 2 mm natural vegetable tanned leather is all materials for making handmade high-grade leather goods. Suitable for making all kinds of backpacks, handbags and other medium-sized and large-scale handmade leather works