1) Smoothness and softness should cooperate with each other. To keep the smoothness and softness of a certain proportion, in order to be able to produce good printing quality paper. This is because the soft paper can make the surface of the paper fully and completely contact with the surface of the printing plate, which is particularly important for bump printing. Sometimes in order to ensure the softness of the paper and have to reduce the degree of calendering paper, so as to reduce the smoothness of the paper. It is often found that the paper with low smoothness and softness has better printing performance than the paper with high smoothness and hardness. Therefore, when making printing paper, it is required to make the paper with high smoothness and softness as far as possible.

 2) The relationship between smoothness and ink absorption. The paper with high smoothness tends to be more compact (especially when the paper machine calendering is used to increase the smoothness), which reduces the ink absorption of the paper. Therefore, the smoothness of the paper with high ink absorption (such as newsprint for high-speed rotary press) should not be too high. 3) Poor smoothness on both sides of the paper. The smoothness of both sides of the paper is inconsistent. Generally speaking, the smoothness of the front is greater than that of the back. As the general paper is printed on both sides, the printing quality is greatly affected.

According to the requirements of printing, the difference of smoothness between the front and back of gravure paper is not more than 20%, that of No.1 offset paper is not more than 20%, that of No.2 offset paper is not more than 30%, and that of relief paper is not more than 25-35%.