An electronic digital tristimulus integrator with interchangeable punched-tape programs corresponding to different illuminants or receptors has been constructed as an accessory for the General Electric Recording Spectrophotometer. The selected-ordinate principle is used. At least one-hundred ordinates are used for the Y integrations. The numbers of X and Z ordinates used are such as to eliminate the need for the adjustment factors usually used. The tristimulus values are presented visually.
W. E. WHITE and D. L. MACADAM, "Universal, Digital Tristimulus Integrator," J. Opt. Soc. Am. 47, 605-611 (1957)