Donaldson Colorimeter

R. Donaldson, a scientist with of the Optics Division of the British National Physical Laboratory, developed his "trichromatic" colorimeter in 1935. This photoelectric instrument became as accurate and efficient as the one that J. Guild had developed for the NPL in the 1920s, but simpler and less expensive. Like Guild, Donaldson created colors by combining different amounts of three primary colors. His instrument, however, had no moving parts and ran on either direct or alternating current. The Donaldson colorimeter was soon used extensively in industry and regarded as the most convenient of the instruments that measured light in three colors.
This example is marked "DONALDSON COLORIMETER MADE BY BELLINGHAM & STANLEY, LTD. LONDON NO. 43883 MADE IN ENGLAND." It was used at the U.S. National Bureau of Standards by Deane B. Judd and other scientists working to establish color standards (a second tag reads "NATIONAL BUREAU OF STANDARDS 94605"). It passed to the Department of Chemistry at the Rensselaer Polytechnic Institute, and came to the Smithsonian in 1981.
Ref: Adam Hilger, Ltd., The Donaldson Trichromatic Colorimeter (London, 1947).
R. Donaldson, "A Trichromatic Colorimeter," Proceedings of the Physical Society 47 (1935): 1068-1073.
R. Donaldson, "A Colorimeter with Six Matching Stimuli," Proceedings of the Physical Society 59 (1947): 554-560.
Currently not on view
Object Name
used by
Judd, Deane B.
Bellingham & Stanley Ltd.
Physical Description
aluminum (overall material)
porcelain (overall material)
lamp housing top: 12.8 cm; 5 1/32 in
lamp housing: 23 cm x 10.2 cm; 9 1/16 in x 4 in
frame: 27 mm x 206 mm x 255 mm; 1 1/16 in x 8 1/8 in x 10 1/16 in
housing: 32 cm x 54.7 cm x 73 cm; 12 5/8 in x 21 9/16 in x 28 3/4 in
place made
United Kingdom: England, London
ID Number
catalog number
accession number
National Bureau of Standards
Measuring & Mapping
See more items in
Medicine and Science: Chemistry
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Rensselaer Polytechnic Institute, Department of Chemistry

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