Sumi ink is a traditional black ink used in East Asian calligraphy and painting. Made from soot and animal glue, it is known for its rich, deep color and smooth application. The ink is often ground on a stone slab with a small amount of water to achieve the desired consistency, allowing artists to create various shades and textures. This ink has a long history, dating back to ancient China, where it was used for writing and artistic expression. Sumi ink is popular among calligraphers and artists for its versatility and ability to produce fine lines and bold strokes, making it an essential tool in East Asian art.