I am a Medical laboratory technologist from Sri Lanka. When I used my carrier in 1983 I used Klett-Summerson colorimeter as the start of biochemistry, which was very simple and durable.

This example is marked "DAVIS-BRUNING COLORIMETER FISHER SCIENTIFIC SERIAL No. 123 Pat 1951 MADE IN U.S.A.” and “115 VOLT 60 CYCLE." The Department of Chemistry of the Rensselaer Polytechnic Institute ...

The report describes a photoelectric tristmulus spot colorimeter which measures the three stimuli X, Y, Z as specified by the C.I.E. (Commission Internationale de I'Eclairage) standard observer ...

Summerson, "A Simplified Test-Tube Photoelectric Colorimeter, and the Use of the Photoelectric Colorimeter in Colorimetric Analysis," Journal of Biological Chemistry 130 (1939): 149-166. Location ...