About calligraphy inks, liquid and solid

Previously, I compared a liquid ink with a solid ink stick, and tested various liquid inks for mountability. I thought I should explain a bit more about liquid inks, since they are actually very convenient and thus suited for people who do calligraphy as a hobby and do not have hours every day to spend grinding ink sticks.

First, calligraphy ink (whether solid or liquid) is made from soot. Traditionally, ink comes in solid form, because ink sticks are easier to store and carry. Ink sticks are basically made by mixing soot with animal glue (胶 in simplified Chinese, 膠 in Japanese and traditional Chinese), which helps to bind the soot together. Animal glue is also the "adhesive" that will hold the soot to the paper. This mixture is often added with some fragrances such as deer musk. The mixture is kneaded to make sure the soot is evenly spread throughout the animal glue, then cast into their final shapes using molds, and left to dry for a long long time. Ink is made by grinding such ink sticks on a wet inkstone. The result is that the ink used for writing calligraphy is made using water, soot, animal glue, and traces of some fragrance.

Liquid ink seeks to duplicate this mixture with the main difference being the kind of adhesive used. Liquid inks can be made using animal glue like solid ink sticks, or it can use a synthetic adhesive. This is also why liquid ink is usually categorised into either animal glue-type ink or synthetic adhesive-type ink. Given that animal glue is organic and will go bad with time when wet, liquid inks usually contain some kind of preservatives, plus other additives to prevent the animal glue from coagulating.

This is also why calligraphy works are usually written with ink made from ink sticks. Calligraphy paper can last a thousand years, but the chemicals (such as calcium chloride, which is used as a stabilizing agent) found in liquid ink may, over time, damage the paper, shortening its life. This is not likely to matter when practising, but for works that are going to last a long time, you really want to avoid that risk, which is why ink made from ink sticks is used. Furthermore, animal glue, when dry, does not melt in water at room temperature. This is a necessary condition since the paper is sprayed with water when mounting a calligraphy work. If synthetic adhesive-type ink is used and the synthetic adhesive melts, the ink will run and spoil the work.

Liquid ink manufacturers try all kinds of ideas to overcome these issues.

For synthetic adhesive-type inks, manufacturers have their own formulations to prevent the ink from running after it has dried. This is also why some of these liquid inks are labeled as "suitable for mounting". If a liquid ink that uses synthetic adhesive is not labeled as such, do not try to use it for a work that will be mounted. Such liquid inks are usually the cheap ones too. In the end, you get what you paid for.

In comparison, animal glue-type inks are usually more expensive. There are animal glue-type inks that use as little chemicals as possible. The less preservative used, the shorter is the shelf-life of the ink, though. And you know that the ink has gone "bad" because it will smell bad. For such liquid inks, they are best used as soon as you open a bottle (aka exposed to air). Animal glue-type inks also tend to coagulate on colder days, but that should not be a problem when indoors and the temperature is warm enough not to be wearing a jacket. Finally, the stuff that prevents coagulation doesn't last forever, and old ink can start to form lumps of soot. This results in diluted ink (the water contains less soot now), and I was told by an ink company that you should not try to grind the lumps of soot since it can result in uneven soot particles that may have an unexpected result when written on paper.

 

These are examples of old liquid ink, resulting in very poor spreading of the ink on paper.

This is what happens when you use old ink (宿墨). Basically, the animal glue in the ink has broken down (degraded), and the ink is now basically soot mixed in water. When animal glue is presented, the mixture is a colloid, and the soot is suspended in the animal glue and spreads out together with the water. Without animal glue, the soot does not spread out with the water, resulting in very poor spreading of the ink.

A more even spread of ink would look like this photo below.

Ink made by grinding an ink stick also faces these issues. First, such inks lack preservatives. So they go bad really fast... In winter, animal glue can last about 3 days left in a room before starting to stink. On warmer days, I had ink stinking after 2 days. When the weather is cold, the ink also coagulates (it starts to feel a bit thicker). You can avoid this in winter by writing in a room which is heated, or by using a heating mat. Yes, they do sell heating mats for inkstones. Such heating mats actually look like the ones used to keep pets warm.

 

Note: Liquid ink that has become old ink can still be used, if the liquid ink uses animal glue. Instead of water, use the old liquid ink when grinding an ink stick. You are basically adding more soot and animal glue into the old liquid ink. For example, in the photo below, the top blotch of ink is old liquid ink. The bottom is when I used that same old liquid ink for grinding an ink stick.

You can see that the old liquid ink has become quite diluted, but once a bit more soot was added, it regained its colour. So instead of throwing away old ink, just use it to save some time when grinding an ink stick. But remember, this only works for animal glue-type liquid ink. Do not mix inks that use different types of adhesive (animal glue with synthetic adhesive) because the different adhesives may react with each other.

Finally, we come to the kind of soot used. Soot is collected by either burning wood (usually pine 松) or oil (油). Soot from wood results in uneven soot particles that also have a more bluish tint when diluted. Soot from oil results in smaller soot particles, a deeper black, gives a more shiny look when dry, and a slightly brown tint when diluted. The type of soot used is usually stated for ink sticks, but if not, you can grind the ink stick and after it has dried, look to see if the part of the stick used is shiny (oil) or dull (wood). Soot from burning lacquer is also used to make ink, so you sometimes see 漆 as the "ingredient" for an ink stick.

In the photo above, the ink on the left is made using soot from oil, while the one on the right using soot from pine. It is fine to mix such inks. I often use a blend of both pine soot and oil soot so that I get a deeper black without too much shine.

I hope this post has helped you understand a bit more about the inks we use in calligraphy.