Subdividing a color space is described for vector error diffusion which includes obtaining color coordinates for each primary color in the color space, and comparing the color coordinates to a threshold value for each coordinate plane of the color space. In response to the comparing, each primary color is grouped into a quadrant of the color space, wherein each quadrant is defined by the threshold value for each coordinate plane. In other aspects, a mapping a color to a closet primary color is described in a color space that includes a display determining color coordinates of the color and identifying a matching quadrant of a plurality of quadrants dividing the color space, wherein the determined color coordinates fall within the matching quadrant. A representative display device searches for the closest primary color within the matching quadrant and maps the color to the closest primary color found.