What's the difference between special ink for pens in Li Xiu?

The color is darker and the quality is better. Special ink is a special ink for Li Xiu pen, which has the effect of darker color and better quality. Li Xiubi is a kind of calligraphy pen, commonly known as soft pen, which first appeared in Japan, similar to China's Zhong Baibi, and is mainly popular in China, Japan, Singapore and other countries.