"Tactical Optical Illusion Squadron". Table B2
Designed by Ugo Crisponi in the style of Ishihara's classic color vision plates, this test places carefully selected red-orange dots against a green-brown background. Normal color vision depends on comparing the spectral responses of the L (long-wavelength, or "red") and M (medium-wavelength, or "green") cone photoreceptors. Individuals with red–green color vision deficiency (Daltonism), however, rely more heavily on luminance and brightness cues than on chromatic contrast. In this design, the background and bomber colors are mathematically chosen to lie along the same color-confusion axis while maintaining closely matched relative luminance. As a result, the iconic swept-wing silhouette of the B-2 stealth bomber becomes effectively "invisible" to observers with anomalous red–green color vision, much as hidden figures disappear in traditional Ishihara plates. Dr. Shinobu Ishihara (1879–1963), a Japanese ophthalmologist, is best known for developing the Ishihara color vision test, the world's most widely used screening method for red–green color vision deficiency. He created the test in 1917 while working with the Japanese military to identify recruits with color vision abnormalities. The original plates were reportedly hand-painted with watercolors. Building on earlier European color vision tests, Ishihara's method proved more effective and remains the global standard used by ophthalmologists, optometrists, military organizations, and occupational health programs.
