1. Process for determining the halftone percentage values of individual priming inks which correspond to a given desired color location during multiple color printing using a color atlas which includes: a plurality of color fields having known graduated halftone percentage values of the individual priming inks, said process comprising the steps of: determining color locations of the color fields defined by color coordinates; storing the color locations of the color fields together with the known graduated halftone percentage values of the color fields; and determining halftone percentage values of the given desired color location based on desired color coordinates of the given desired color location, said step of determining halftone percentage values further including the step of: interpolating the halftone percentage values of the given desired location from the stored color coordinates and the stored halftone percentage values of the color fields using a differential weighted compensating calculation, wherein a relationship between the stored halftone percentage values and the stored color coordinates of the color fields in a vicinity of the desired color location is approximated by approximating functions, such that greater differences between stored color coordinates and the desired color location are weighted less in the differential weighted compensating calculation than smaller differences.