The ratio difference between the three:
1, ultra-clean (ultra-clean leather, also known as ultra-clean leather): leather 80%, straw paper 20%.
2. Clean leather: 70% leather and 30% forage.
3. Cotton: 60% leather, 40% forage.
In addition to the above three kinds, there are pure leather rice paper, all made of leather.
Extended data
The heavier the leather composition of rice paper, the better the paper bears tension and the better the quality; The corresponding use effect is: the higher the proportion of sandalwood, the richer the ink layers, the better the ink moistening effect, and the more able to withstand repeated rubbing with pen power without damaging the paper surface.
This is one of the reasons why cotton Xuan paper is mostly used for calligraphy and leather paper for painting. It's not that you can't write with clean paper and special paper, but cotton rice paper can basically meet the needs of calligraphy.
China Net-Jiyazhai teaches you how to distinguish the quality of Xuan paper (see the paragraph above-there are many kinds of Xuan paper).
Baidu Encyclopedia-Sufangzhai (Xuan Paper Classification)