《天工开物·中篇·杀青》
制作精良的纸非常洁白，可以用来书写、印刷和制柬帖；粗糙的纸则用于制作火纸和包装纸。
精者极其洁白，供书文、印文、柬启用；粗者为火纸、包裹纸。
The well-made paper is very white, and can be used for writing, printing and making invitations; coarse paper is used for making fire paper and wrapping paper.