Types of ink

Here we introduce the types of ink, the glue that makes up ink, and its fragrances.

Oil Soot Ink

Oil soot ink with almost no impurities and little change in ink color

It is well known that pine soot ink was developed in China, but oil soot ink is said to have been pioneered in Japan.
The raw materials for oil soot carbon particles include rapeseed oil, sesame oil, tung oil, and camellia oil, among which rapeseed oil is the most widely used.
Compared to pine soot carbon particles, oil soot carbon particles are extremely small and uniform. The quality of good ink is judged by its glossy, deep jet-black tone with a sense of depth when used as dark ink.
As for light ink, good quality is indicated by a delicate shading effect, producing a black with subtle brownish, purplish, or bluish tones.
Oil soot ink contains almost no impurities and shows little variation in color.

Furthermore, its contact with the inkstone is smooth, and the grinding surface has a glossy shine. The better the oil soot ink, the stronger this gloss becomes.
On the other hand, inferior quality includes reddish-brown or whitish tones that lack depth even as dark ink, or rough-textured light ink lacking dimension.
However, judging quality requires abundant experience and keen insight, and the paper quality also significantly affects the ink’s color.
Without comparing inks on the same paper, it is difficult to make an accurate judgment.

Refined Soot Ink

Compared with pine soot ink or oil soot ink, it “turns black faster”

Generally, refined soot ink is also called Western soot ink, made from raw materials such as mineral oil and carbon black.
It is often used for practical and widely available inks, and compared to pine soot and oil soot ink, its feature is that it “turns black faster.” The drawback, however, is that it lacks the subtle beauty of traditional ink that “shines in seven colors.”
Although ink liquid has unfortunately become mainstream in recent years, to preserve brushes and inkstones, Western soot ink is recommended over ink liquid, even if it is considered inferior to pine soot or oil soot ink.

Ink Glue

Glue that greatly affects the characteristics of ink

Glue plays the role of binding carbon particles together in the ink-making process.
The word “glue” originates from “boiled skin,” and it is made by boiling the connective tissues (between outer skin and flesh) or bones of cow, horse, or deer, then pouring into molds, cooling into sheets, and drying.
Good-quality glue must be transparent, strongly adhesive, and have high gel strength.
However, if the gel strength is too high, the ink becomes too hard, making it difficult to grind properly.

Conversely, glue that is weak in adhesiveness, with low gel strength and cloudy color, is of poor quality.
The role of glue in ink is to help form ink blocks by mixing with carbon particles.
Moreover, when grinding ink on an inkstone, it produces a glossy ink color, another essential function.
Glue is made from boiling down animal bones, skins, and intestines into a solid substance.
Since soot particles do not dissolve in water but separate, gelatinous glue is necessary as an intermediary to bind soot with water.
By coating soot with glue, it can dissolve into water and become liquid ink.
In other words, the friction felt when a brush touches paper is largely due to the sensation of glue.
It is said that “thick ink feels sticky,” but in reality, concentration and viscosity are different: concentration refers to the ratio of carbon particles to total liquid, while viscosity refers to the ratio of glue to total liquid.
Although grinding a lot of ink at once increases both simultaneously, making them seem identical, they can be controlled separately by ink selection, grinding methods, or adding glue.
Since glue is animal-based, it emits a strong odor, so fragrance is mixed to mask the smell.
How strong this odor can be is evident in the smell of “aged ink” left after grinding: initially fragrant with perfume, it eventually gives off a powerful stench that overwhelms any fragrance.

Ink Fragrances

Ink that calms the mind while grinding

Fragrances serve to mask the unpleasant odor of glue and to promote mental focus for the person grinding the ink.
Fragrances are broadly divided into natural and artificial types.
Natural ones are further divided into plant-based and animal-based. Among these, “plum blossom fragrance” (plant-based) and “musk” (animal-based) are well-known.
Artificial fragrances include “musk ambrette” and “xylol,” which are used in blended perfumes.
In addition to suppressing glue’s odor, fragrances play the important role of helping the ink grinder achieve mental concentration and a calm atmosphere.

Red Ink (Vermilion Ink)

Vermilion ink, once highly expensive

In ancient times, vermilion was called “tan,” and as celebrated in the Manyoshu poem, “Nara, resplendent in blue and vermilion…,” vermilion was painted on the pillars of temples and buildings in Heijo-kyo during the Tenpyo era.
It served not only as a preservative but was also treated as highly precious due to its brilliant color.
In the late Muromachi period, when vermilion arrived in Hakata, Kyushu, mining and selling vermilion by commoners was prohibited, and its production was also forbidden.
In 1609, the Tokugawa shogunate permitted the production and trade of vermilion, and manufacturing began.
It was not until the Meiji era that its general use was allowed, such as for corrections and seals using vermilion ink.
High-grade vermilion ink is made from processed mercury, producing a vibrant red that does not fade over time.
In contrast, cheap vermilion ink uses pigments instead of mercury, and its color deteriorates with age.
Therefore, when seeking high-quality vermilion ink, it is crucial to choose one with higher density to confirm mercury content.