noncolor

:  a drab or muted color or a color such as black, white, or gray as distinguished from red, blue, yellow, etc. … the furniture is upholstered in fabrics that are natural not only in fiber but in color. … Only a few notes of red, in a small table and a pair of chests, punctuate the range of noncolors. — Joan Chatfield-Taylor —often used before another noun noncolor photography [=black and white photography]