Unlike the Ishihara patterns that may be found online and viewed on a computer monitor, this color vision test is designed to produce accurate test results in determining color blindness and the degree of color blindness. Since color reproduction may vary from computer monitor-to-computer monitor, the best and most accurate method of testing for color blindness still comes from official Ishihara album-type books.
Although the full Ishihara test consists of 38 plates, usually the existence of a deficiency is obvious after a few plates.
The Ishihara Color Testing Book is accepted by leading authorities as a simple and accurate method for discovering congenital color blindness and red-green blindness in both complete and incomplete forms. Also known as Protanomaly and Deuteranomaly, "red-weakness" and "green-weakness", respectively, are the two most common types of color deficiency.
More comprehensive results can be obtained with the addition of more testing plates. The 38 plate test is the most comprehensive.