Royal Canadian Navy (RCN) Colour Vision Test Lantern
Accession Number: 2014.ep.13.1-2
The RCN Colour Vision Test Lantern is contained in a rectangular wooden box painted black, the top of the box forming a half hexagonal shape with a metal handle bolted to the top. Controls are mounted vertically on the rear face of the instrument. There is a control panel with two floodlights encased in metal of 5 cm in length each directly below the top of the box. Directly between the two floodlights there is a metal switch. Below this metal switch there is a nine-sided brass knob (6.5 cm in diameter), each side numbered with an engraved white numeral between 1 to 9. Adjacent to and above the knob there is a microammeter, a dial measuring microamperes up to 200 μA at numerical increments of 50 μA. Below the left flood light there is another black metal switch. Directly above the base of the instrument there are two metal switches; the left switch is the “110v switch” and the right switch is the “photronic cell switch.” Directly adjacent to the left and right of these switches there are two knobs: the intensity control and shutter control. Between the right switch and the right knob there is an electrical cord of rubber and cloth fibers. The wooden sides of the box extend 7.5 cm beyond the control panel.
Alternative Name: Colour blindness test
Wood, Metal, Brass, Pyrex Glass, Rubber, Cloth
Uppermost rim above control panel: “28.” On microammeter: “MICROAMPERES D.C.; WESTON; MODEL: 301;” measurements “0, 50, 100, 150, 200.” On each of two metal switches directly above the base: “ON;” “OFF.”
13.1: Height = 34, Width = 27.25, Length = 37.5. 13.2:
The RCN Colour Vision Test Lantern was developed in order to accommodate the Royal Canadian Navy requirement to test all navy personnel for normal colour vision. The lantern was designed to administer tests to navy personnel who failed the standard Ishihara colour vision test, a rapid and simple testing method (Solandt and Best 1943, 18).
During the test, the subject sits 20 feet from the lantern in a dark room and identifies the lantern’s projected colours verbally and by raising the hand as instructed (Solandt and Best 1943, 20). On the object, the two floodlights on the control panel are “provided to illuminate the controls and facilitate making records” (Solandt and Best 1943, 19) for the individual administering the test. The brass knob in the centre of the panel controls an 8-inch brass wheel inside of the instrument, which rotates colour filters of polished pyrex glass (Solandt and Best 1943, 18-19). As such, the instrument is capable of nine colour combinations at any given time and the pyrex filters can be changed to create different combinations (Solandt and Best 1943, 18). The wooden sides of the box extend 7.5 cm beyond the control panel in order to “shield the subject” (i.e., the participant whose is undergoing a vision test) from the control panel floodlights (Solandt and Best 1943, 19).
Good: Electrical cord torn at base and frayed; no other visible damage.
Date of Manufacture: c. 1938
Prof. D. Y. Solandt and Prof. Charles H. Best, Departments of Physiology and Physiological Hygiene, University of Toronto.
Cited here and for further details on instrument components and function, see:
Solandt, D.Y. and C.H. Best. 1943. “The Royal Canadian Navy Colour Vision Test Lantern.” Canadian Medical Association Journal (CMAJ) 48: 18-21.
Solandt and Best additionally acknowledge the Physiology of Vision of the Medical Research Council and the designers of the British Board of Trade Lantern as significant resources in the development of the RCN test lantern (1943, 18).
Date of manufacture (1938) listed on 1980 catalogue record; no other authoritative confirmation of this date.
According to Solandt and Best, the RCN Colour Vision Test Lantern was developed by D.Y. Solandt “under the auspices of the Subcommittee on Naval Medical Research of the National Research Council and the Medical Research Unit of the Royal Canadian Navy” (1943, 18). At the time of publication, the lantern had been authorized for use by the Royal Canadian Navy (Solandt and Best 1943, 18).