Everybody help me popularize my knowledge of calligraphy. There are several kinds of paper. How much is this inch commonly used? They are all bigger than A4 paper. How big is that? How much is a knife

Everybody help me popularize my knowledge of calligraphy. There are several kinds of paper. How much is this inch commonly used? They are all bigger than A4 paper. How big is that? How much is a knife and a half? According to the processing methods, Xuan paper can be divided into three types: raw Xuan, cooked Xuan and semi-cooked Xuan, and the varieties of Xuan paper can be divided into three types according to the proportion of raw materials: cotton, clean skin and extra clean. According to the specifications, it can be divided into three feet, four feet, five feet, six feet, eight feet, two feet and six feet. According to the thickness, it can be divided into flower tying, cotton picking, single announcement and clip announcement. According to the paper pattern, it can be divided into single silk road, double silk road, rib, turtle pattern, white deer and so on; In addition, there is a difference between raw paper and cooked paper, a kind of "knife" paper. It describes the ancient papermaking. The paper that has just been made is neatly placed one by one, without being scratched or stained with any ink. As soon as the knife fell, a thick pile of vertical blanks was immediately split, and the burr did not fly, and the neat sound was still in my ear ... Grasping this feeling, I could completely cut off the "knife". But of course, there are no two sharp knives in the world, and there is no comparable strength. The result is specious, let's just calculate it, take the approximate value it can make as a sample, so there are many names, which creates this romantic and untrue quantifier, commonly known as "knife". Generally, one knife 100 sheets of paper, and there were 25 sheets of 70 sheets in ancient times.