CIE x,y coordinates from an inexpensive projection colorimeter

The present paper reports an extension of the design for a projection colorimeter originally proposed by Riggs, 1964. A technique and the necessary calculatory formulas are presented through which the definitions of colors produced by the instrument may be defined in terms of CIE x,y coordinates of chromaticity space. Data on the accuracy of measurements obtained from a random sample of naive Os are also reported.