At left, a Perkim-Elmer spectrophotometer, model 137, from the 60s. Used mostly in organic-chemistry for teaching and research. Produce a spectrum of transmited intensities by wavelenghts. This one has an sodium chloride prism as dispersive medium, a photoelectric detector and is used in infrared. ..

At right an HP 8451A Diode array Spectrophotometer. A single beam,microprocessor controlled, UV-visible spectrophotometer which opperates at high speed in the full range of 190 to 820nm wavelenght. This machine was donated by profesorDr O.E. Hileman, Jr. McMaster University.