Farnsworth explored past theories on color vision and blindness. He wrote the following statement regarding color vision:
For industrial purposes color vision can be divided usefully into three groups: normal, partially defective, and color blind. Two standard tests are sufficient to make this analysis:
A desk-type lamp has been designed to furnish standard illumination for these tests: “ADE10” Easel Lamp, Macbeth Corporation, 227 West 17th St., New York 11, N.Y.
The three degrees of color vision are diagnosed in this way: