Ultra Scarce 1940s Glenn Colorule for Testing Color Vision oval dish and with the aid of

and with the aid of a magnifier I am able to read some printed text on it—“Funnel Piller Gun / Somers Bros / Brooklyn NY

clicks and pops

Some wear to the lacquer around the edges on the sides

What I especially like about this "scale of values"

and those big pencil-drawn spots drawn on the larger horse

Ultra Scarce 1940s Glenn Colorule for Testing Color Vision oval dish and with the aid ofI have found a bunch of academic papers and studies discussing the use of the Glenn Colorule, but can't find even a picture of another out there anywhere. There are records of in a few academic libraries, so I know it was produced by s explained on the box text, it was made to be used to test the color vision of observers, to test the quality of light sources, and or to demonstrate disagreement caused by "pseudo," or false, color matches. There's a