(1) the first layer of skin with the grain of cattle and sheep, pig, leather, natural scar and blood rib mark, and occasionally during the processing and utilization of cut belly parts is extremely low, the first layer of skin and imported cattle number mark. Full grain leather thickness and density of the pores can be to distinguish between what belongs to animal leather. There are many kinds of cowhide, such as milk, meat, cattle, cattle, buffalo, buffalo, castrated male and female. In China there are yellow leather, water buffalo, yak skin and cattle yak leather etc.. Among them, the water buffalo pores thicker and more sparse; yellow leather is more thin and thick than the water buffalo pores. The pores of the sheepskin is more fine and dense and a little bit of slope, there are two main categories of sheep skin and goat skin. Because the hair is a handful of 3~5 root distribution rules of pigskin, so it is easy to distinguish, commonly used artificial breeding pig, and wild boar skin, known as the South American wild boar, wild boar leather has obvious pores and grain characteristics of pigskin, due to its special structure of collagen fibers, can be processed into a very soft the garment leather or leather gloves, with very high value. In addition, an ostrich, crocodile, alligator, lizard, snake skin, skin, skin of bullfrog skin seawater (with shark skin, skin, skin, COD, COD eel skin, pearl skin), fresh water fish (grass carp, carp skin and scaly skin), hairy skin (Yin Hu fox skin blue fox, wolf, etc.), such as skin is easy to identify, skin, and could not be made of two layers of skin.
The first layer of skin is the original skin directly and processing all kinds of animal, animal or the thicker cortex of cattle, pig and horse skin after depilation cross into upper and lower two layers, the upper part of fibrous tissue is processed into a variety of tight head skin.
(2) the skin of the two layer is a loose layer of fibrous tissue, which is coated with PVC or PU thin films by chemical material spraying or on.
Therefore, the effective method to distinguish the head skin and the two layer is to observe the longitudinal fiber density. The head skin is composed of a dense and thin fiber layer and a slightly loose layer which is tightly connected with each other. The fibrous tissue layer two layer of skin is only loose, only in the spraying or polishing chemical raw materials can be used to make leather products, it has certain characteristics of the natural process of elasticity and plasticity, but the strength is poor, the thickness of the same as the first layer of skin.