Ultra Scarce 1940s Glenn Colorule for Testing Color Vision oval dish Some wear to the lacquer

Some wear to the lacquer around the edges on the sides

clinical looking dark green box with silvery white print and one initial--"M" in this case

and there is a red dyed bone hook included

I myself might be inclined to use it as a vase rather than a watering can (or simply to put it on a shelf to display as an object) but the handle on the back certainly makes it functional for watering the plants

What I especially like about this "scale of values"

Ultra Scarce 1940s Glenn Colorule for Testing Color Vision oval dish Some wear to the lacquerI 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