Inksticks (Chinese: 墨 Mò; Japanese: 墨 Sumi; Korean: 먹 Meog) or Ink Cakes are a type of solid ink used traditionally in several East Asian cultures for calligraphy and brush painting. Inksticks are made mainly of soot and animal glue, sometimes with incense or medicinal scents added. To make ink from the inkstick, it has to be continuously ground against an inkstone with a small quantity of water to produce a dark liquid which is then applied with an ink brush. Artists and calligraphists may vary the thickness of the resulting ink according to their preferences by reducing or increasing the intensity and time of ink grinding.
The earliest artifact of Chinese inks can be dated back to 12th century BC, with the use of charred materials, plant dyes and animal-based inks being occasionally used with mineral inks being most common. Mineral inks based on materials such as graphite were ground with water and applied with ink brushes. Indeed, the mineral origins Chinese inks were discussed by Eastern Han scholar Xu Shen (許慎, 58 CE – ca. 147 CE). In Shuowen Jiezi, he wrote "Ink, whose semantic component is 'earth', is black." (墨，從土、黑也), indicating that the character for the ink ("墨") is composed of black ("黑") and soil ("土") due to the earthly origins of the dark mineral used in its production.
The move from using graphite inks to soot and charred inks occurred prior to the Shang dynasty. From studies of ink traces from the artifacts from various dynasties, it is believed that the inks used in Zhou dynasty are quite similar to those used in the Han dynasty. However these early inks, up to the Qin dynasty, were likely stored in liquid or powder forms that do not preserve well and thus their existence and constitution can only be studied from painted objects and artifacts. Physical proof for these first "modern" Chinese soot and animal glue inks were found in archaeological excavations from tombs dated to the end of the Warring States period around 256 BC. The ink were formed by manual labour into pellets, which were ground into ink on top of a flat inkstone using a smaller stone implement. Many pellet-type inks and grinding implements have been found in Han tombs with the large ingot-types inks appearing in late Eastern Han. The latter inks have physical markings which indicate that kneading was used in their production.
One of the first literary records of inkstick production in China is from qimin yaoshu (齊民要術) written during Northern Wei. Elaboration of the techniques, technical requirements, and ingredients were also noted in scroll ten of yunlu manchao (雲麓漫鈔) and the "ink" chapter of tiangong kaiwu (天工開物), the notable Ming dynasty encyclopedia by Song Yingxing (宋應星).
In general, inksticks are made with soot and animal glue, with other ingredients occasionally added as preservatives or for aesthetics:
- Soot: Soot is produced by anoxic burning of oils such as tung oil (桐油), soybean oil, tea seed oil, and lard, or from wood such as pine.
- Animal glue: Egg white, fish skin, or ox hide glues are used to bind the inksticks together
- Incense and medicines: To improve the physical aesthetics of the inkstick, incense and herb extracts from Traditional Chinese medicine such as cloves, comfrey, ash (Fraxinus chinensis) bark, sappanwood, white sandalwood, Oriental sweetgum, or even deer musk and pearl dust were added. These ingredients may serve as preservatives for the inkstick.
The ingredients are mixed together in precise proportions into a dough and then kneaded until the dough is smooth and even. The dough is then cut and pressed into a mold and slowly dried. Badly made inksticks will crack and craze, due to inadequate kneading, imprecise soot to glue ratio, or uneven drying.