Answer
Monochromatic: Redon's noirs are characterized by their limited color palette, primarily consisting of shades of black and white or a single color. This monochromatic approach creates a sense of unity and drama, allowing Redon to focus on the emotive power of line, form, and composition. The absence of vibrant colors heightens the impact of the subject matter, inviting viewers to delve into the psychological and symbolic aspects of his artworks.