Gorky: Paper-making

Paper making to the old Samarkand recipe of mulberry bark. 

Captured Chinese prisoners in 870 brought with them the secret of making paper – bamboo, cotton and cloth substrates. However, cotton paper, the only local material applicable, bled writing ink, although ok for lanterns or posters. After trials, the soft under-bark of one-year-old branches from mulberry trees could be used. 

Sericulture [silk farming] was and is a major industry and generates a lot of fresh mulberry branches harvested for their leaves for the silkworms. The availability of good quality paper allowed the creation of large libraries and linear written argument. This enabled the Abbasid translation movement and the learning of Ibn Sina as well as his huge output because of the much lower manufacturing costs

From my conversations with Dad, supplemented by Wikipedia:
The Chinese invented paper making, but initially used it for wrapping things, for padding and protection. They fiercely protected their methods, and the techniques were slow to spread.
The first paper mill in the Islamic world was founded in Samarkand in the eighth century (C8), and used water power to power trip-hammers to prepare the pulp.

The raw paper was then polished to a smooth surface using shells and stones

The technology slowly spread through the Islamic world, into Europe (C11) and India (C13)