Discovering and Developing Talents © 2002 Stephen Holland HiddenTalents.org

1 - Explaining Color Deficiency 2 - Traditional Tests 3 - Holland's Online Tests 4 - Percent Test 5 - Brown Test - Results 6 - Color Pencils- Results 7 - Art Test 8 - Thread Test for Children

2. Traditional Color Deficiency Tests The best source for purchasing official tests that I have found is Richmond products.

A. Ishihara Test The Ishihara test of numbers made of colored dots is the most common test. It is simple, but not highly accurate or informative. It is mainly useful for quick screening, but according to the Optometry manual, is not to be trusted too much. This is one example, plate #8. Instructions by Dr. Shinobu-Ishihara that came with it say, "The normal read the figure for 2, but the colour-blind can hardly read it." My analysis below suggests that this sample test may miss people with green deficiency who would pass the test . According to the instructions, people with normal color vision can see a 2. When I dimmed the red to imitate weak red vision, it looks like this, so that people with weak red cannot read the number 2 very easily. However, when I dimmed the green to mimic weak green vision, the green dots went darker, but the red number stayed a bright red.

Dvorine Pseudoisochromatic Plates The Dvorine Pseudoisochromatic Plates are reportedly more accurate tests than the Ishara plate.

Farnsworth-Munsell 100 Hue Test An excellent test is the Farnsworth-Munsell 100 Hue Test which gives a person many colored caps with slight variations of colors, and asks him to sort colors that are very close together. However, it is slow and expensive to administer by a specialist, and is not common. A company involved with color, such as textiles, dyes, electronics, art work, etc. would be wise to buy the test for its own employees. The test apparatus (left) only costs a few hundred dollars. There is also a simpler D-15 test with only 15 colors, but the bigger test would be better for companies that work a lot with color.

Anomaloscope The best color perception test is the anomaloscope. It involves changing the brightness of red and green lights to match a "standard yellow." The Nigel Anomaloscope is an example. Again, the tests are expensive and need a specialist to do properly, but they give exact measurements of red and green problems. To quote the 1998 New Zealand Health Technology Assessment (NZHTA) analysis of colorblind tests, "-------- "The anomaloscopes are regarded as the gold standard test for impaired vision on the red-green axis and are therefore used for diagnostic purposes."

Some More Links for Tests An excellent scientific critique of color deficiency tests is the 1998 New Zealand Health Technology Assessment (NZHTA) Many official tests can be purchased at Richmond Products. A Poster for testing young children, by Golden Retrieval, Inc. Looks interesting.