Color agnosia

Color agnosia ("agnosia" is Greek for non-knowledge), also known as "cerebral achromatopsia", is a medical or psychological condition that prevents a person from recognizing colors even though the eyes are capable of distinguishing them. It is a specific form of agnosia and generally results from damage to the visual cortex, often in V4 (as opposed to most other kinds of color blindness, which stem from problems with the photoreceptors).