Farnsworth Dichotomous Test

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:

• Pseudo-isochromatic Plates for Testing Color Perception (Revised Selection), American Optical Company, Southbridge, Massachusetts.
• Farnsworth Dichotomous Test, Psychological Corporation, 522 Fifth Avenue, New York 18, N.Y.

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:

• Pass-A.O. Plates-NORMAL
• Fail-A.O. Plates-PARTIALLY DEFECTIVE
• Pass-Dichotomous-PARTIALLY DEFECTIVE
• Fail-Dichotomous-COLOR BLIND