In the 1940s Dean Farnsworth created a simple system that could test for color blindness. This system is still used today by designers, photographers, colorists and medial professionals to test for color blindness and pinpoint areas of color deficiency for individuals.
The test contains four sets of color hues that each contain 25 discs with variations of that hue. Under a light that mimics natural light, the discs need to be arranged to create the correct gradient of hue differentiation. Since there are a total of 100 discs, this test is relatively time consuming. This test can be taken online, however, the accuracy isn’t the same as in the physical testing environment since color calibration and backlit displays can change the appearance of the hues.
The results of the color test are based on observer errors and can determine visual acuity, color blindness and visual system defects such as poor cone sensitivity.