What are the tests involved for color blindness?

Usual test: Ishihara: The usual test for color blindness is the ishihara test, with 38 circles of colored dots. Each of the circles of dots contains a hidden number made up of certain colors of dots. Depending on whether or not a person can read the number in the circles, his type of color blindness can be diagnosed. Simpler tests include asking a person to look at red and green numbers (or lights) and say the color.

Color plates: The most commonly available test is the ishihara color recognition plates which present numbers buried in dots of color over the axis of color confusion for the deficient. This can tell severe from mild color deficiency. Other tests are availbale to tell which type of color deficiency you have. This does have some occupational significance.