Patent ID: 7679783

Claim:
A system for producing pure gray tones on a multicolor document output device comprising: means adapted for receiving non-linear device independent color data defining an image inclusive of an edge portion and having a plurality of pixels, each pixel having at least three color components, corresponding to an associated electronic document; storage means adapted for storing a plurality of preselected tolerance values; means adapted for generating difference values associated with a plurality of components associated with each pixel; comparison means adapted for comparing each of the difference values to a preselected tolerance value; extraction means adapted for extracting gray scale data from the edge portion of the received non-linear device independent color data corresponding to a single color space in accordance with an output of the comparison means; output means adapted for outputting modified device independent data including a color data portion and an extracted grayscale data portion; and conversion means adapted for converting the modified device independent data to a device specific colors space associated with at least one selected document processing device; wherein: the device independent color data includes coordinate value data representative of X, Y and Z illuminant coordinate values, and the conversion means includes means adapted for converting coordinate value data to the modified device in accordance with the equations, | X/X w −Y/Y W |<Δt xy and | Z/Z w −Y/Y W |<Δt zy , wherein X W , Y W and Z W are defined as source illuminant values, and Δt xy and Δt zy preselected tolerance values.