ink black; ink color
Refers to the deep black color of sumi ink, often used in artistic or descriptive contexts.
彼女の着物は墨色で、とても落ち着いた雰囲気だった。
Her kimono was ink black and had a very calm atmosphere.
墨
Stars were shining in the ink-black sky.
Compound of 墨 (sumi, 'ink') and 色 (iro, 'color').