The Ishihara color test is a test for color blindness. It was named after its designer, Dr. Shinobu Ishihara (1879-1963), a professor at the University of Tokyo, who first published his tests in 1917. It makes use of the peculiarity that in red-green blindness, blue and yellow appear remarkably bright compared to red and green. It consists of a number of colored plates, on each plate is printed a circle made of many different sized dots of slightly different colors, spread in a random manner. Within the dot pattern, and differentiated only by color, is a number. What, or even if, a number is visible indicates if and what form of color blindness the viewer has. The full test consists of thirty-eight plates, but the existence of a deficiency is usually clear after fewer plates. The Ishihara Color Charts are accepted by leading authorities worldwide as a simple and accurate test method. The color plates are available in an album-type book for ease of handling. The books are printed in Japan and are protected by international copyright. Graham-Field has been the exclusive North American wholesale distributor of Ishihara Tests for over 30 years.