this relates to an identification system for authenticating labels and cards . each label or card would be provided with authenticating characters which are printed in color and which are at least in part in overlapping relation so as to make it difficult to identify the individual characters by eye . however , when a pair of overlapping characters is viewed through a colored filter , depending upon the color of the filter , one or other of the two superimposed characters would appear . by providing the authenticating characters in a preselected arrangement and utilizing colored filter segments in a similar preselected arrangement , only those authenticating characters which form part of the authenticating information would appear .