This study explored the technical aspects of brushing process of metal types printing through veteran's testimony and actual experiment.(1) In general, the brushing process was conducted by preparing materials such as chinese ink, book paper and tools, followed by fixation of printing board into the frame, painting chinese ink on the printing face, placing book paper, wax brushing, and removing the book paper. This process was repeated in order until the necessary quantities of printing were produced, and then, the printing board was disjointed for the next usage. This study thoroughly investigated these processes. (2) Ink brush and brush were both used as the brushing tool. Ink brush was made from ear of grain, and brush was developed by waxing hairs of horse or human. (3) Printing ink was made by liquefying thick soots of low quality. When using ink in solid form, it was soaked in water for 2-3 days, or boiled prior to usage. (4) Sizes of printing board, printed book, and handmade paper were counted prior to trimming margins of book paper. (5) In oder to obtain printed outputs of high book-quality, it was essential to carefully control various factors of the brushing process systematically, such as evenness of printing face, thickness of ink, amount of ink on the printing face, absorptiveness of book paper, absorbing amount of book paper, and brushing techniques of rolling and pounding. Theses processes could be successfully conducted through repeated practices rather than theoretical knowledge. This study is the first attempt to experimentally examine the relationships among ink characteristics, printing aptitude of book paper, and brushing techniques.