Monochrome
Using one colour only, in different lights, darks and strengths; often also means black and white.
Also: monochromatic, single-colour scheme
Monochrome means one colour. A monochromatic scheme takes a single hue and varies it: pale blue, mid blue, navy. The result is calm and unified, and depends on texture and contrast of light and dark for interest. In photography and film, monochrome usually means black and white, or an image toned in one colour such as sepia brown. Older computer screens that showed only green or amber text on black were also called monochrome. In fashion, a monochrome outfit is one colour from head to foot.