1. Method of creating a gamut boundary descriptor of the actual gamut boundary of a color device comprising the steps of: in a transformation color space, selecting gamut boundary colors sampling the surface of said actual gamut boundary, by using said selected gamut boundary colors, generating a network of elementary polygons representing said actual gamut boundary, each selected gamut boundary color belonging to an elementary polygon, generating said gamut boundary descriptor from said network of elementary polygons, through a smoothing or an interpolation of said network of said elementary polygons in order to create a gamut boundary descriptor that is closer to said actual gamut boundary than said network of said elementary polygons, wherein said smoothing or interpolation: does not change the position of the vertices and at the edges of elementary polygons that belongs either to a line or a point of discontinuity of said actual gamut boundary, either to a line or a point of discontinuity of curvature of said actual gamut boundary, and/or does not change the discontinuity of curvature of said actual gamut boundary at the vertices and at the edges of elementary polygons that belongs to a line or a point of discontinuity of curvature of said actual gamut boundary.