Patent ID: 7460283

Claim:
A method of generating a color separation table that stores grid point data of printing material colors used in a printing apparatus correspondingly to grid points that are defined by predetermined input colors for converting the predetermined input colors to the printing material colors, the printing material colors including a special color other than the predetermined input colors and the printing material colors corresponding to vertices of a solid formed by the grid points, said method comprising: a special color point setting step, of setting a point of the special color on a side connecting two vertices of the solid; a secondary color point setting step, of setting a point of secondary color between the special color and a color of the vertex that is one of two vertices of the side on which the special color is set; a table data generating step, of, for the grid points on a line connecting two vertices of black and white on the solid, a plurality of lines running on the surface of the solid and connecting the two vertices through the vertices corresponding to the predetermined input colors or the printing material colors on the solid, a line running on the surface of the solid and connecting the two vertices through the set special color point and a line running on the surface of the solid and connecting the two vertices through the set secondary color point, obtaining the grid points data based on the color measurements of predetermined patches; and an interpolation step, of dividing the solid by the lines into a plurality of solids which include the lines as a side and executing an interpolation process on the plurality of divided solids based on the grid point data of the grid points on the lines of each of the divided solids to obtain grid point data for the grid points located on other than the lines in each of the divided solids.