The typical outline color in ukiyo-e prints is black. In the standard production process, the artist’s design was transferred to a keyblock, whose raised lines established the image’s contours and was usually printed with black ink.
Early ukiyo-e prints were often monochrome, known as sumizuri-e, meaning “ink-printed pictures.” Color was initially added by hand, but later developments used separate blocks for different colors. The black keyblock remained important because it clarified figures, clothing, architecture, and landscape forms after the color blocks were printed.
“Typical” does not mean every ukiyo-e print has identical black outlines. Some later works used colored or softened contours, especially in specialized styles and landscape prints. Hokusai’s Great Wave, for example, is associated with strong blue areas and distinctive linework, while later artists experimented with outline colors and Western-influenced pigments.
The outline is also not painted onto a finished image as a final decorative step. Ukiyo-e was a collaborative woodblock process involving a designer, carver, printer, and publisher; the keyblock and registration marks helped the separate impressions align.