Making calligraphy ink from acrylic paint requires that you have a paint with a runny, thin consistency, but also one that will hold up under use and not dissolve over time. You can use either premixed artist's acrylic paints or pure pigments to make your calligraphy ink. Using prepared acrylic paints is easier and saves a few steps, resulting in a nice consistency ink with long-lasting durability.
Acrylic paint is available in a variety of forms, ranging from interior latex house paint to artist-quality paint to dry pigments. Depending on your level of proficiency with paint-making and how much work you want to put in, you can make calligraphy ink either from artist paint in tubes or by mixing your own paint from scratch with colored pigments. If you are a hobbiest, and your joy is in doing calligraphy, it's probably best to make your ink by diluting artist-quality paints from tubes.
Artist mediums are available in a variety of surface finishes ranging from matte to high-gloss. Mediums are clear acrylic and used to thin paint without compromising their pigment or their consistency. It's necessary to use some medium when you mix your calligraphy ink to maintain the integrity of the paint so it doesn't become overly diluted. Choose what kind of finish you want your ink to have, matte or glossy. Then it is simple enough to buy the medium in that finish to mix with the paint.
Always mix distilled water with your medium to give the finished ink a good consistency without overly diluting it with water. The ideal base mixture of water to medium is 50/50. The quantity depends on how much ink you want as an end product. After you prepare your medium and water mixture, add a small amount of artist paint at a time and mix with a wooden stick to a smooth consistency. Keep adding the paint up to a total of 50 percent of the mixture, stirring until smooth. It should be the consistency of thin cream when you're finished.
It's important to maintain the pH of the overall mixture to no less than 8. When the pH falls to lower than 8, the consistency of the paint becomes thick and cheese-like and is of no use to you as ink. You can test the pH with litmus paper or use the smell test. The ink should have a slight smell of ammonia, which indicates the proper pH. If it looses this smell, add a few drops of ammonia to return it to the correct level.
Something else to watch out for is foaming. Because the paint has surfactant already added, as you mix it with the water/medium combination, it may start to foam. Add a few drops of defoaming agent to prevent this from occurring. Follow label directions for the correct amount.
Once you have achieved the right consistency for your calligraphy ink, you will need to bottle and preserve it. Pour it into a plastic squeeze bottle with a dispenser tip or an ink bottle. In either case, make sure you have a proper top that will seal to keep the ink airtight.