F 2 Tritan Colour Vision Test Plate
 Catalogue Number: 4409 F 2 Tritan Colour Vision Test Plate Category: Equipment Sub-Category: Colour Vision Test Designer/inventor: Dean Farnsworth Description Of Item: Colour vision test plate on card mounted on board and covered in perspex. The image is made of two overlapping squares, one yellow-green and the other blue, on a background matrix of purple dots. Image size: 115 x 115 mm, mount: 150 x 200 mm. The test was designed as a tritan screening plate. Historical Significance: Dean Farnsworth designed the F1 tritan screening plate containing two numerals, based on plate 6 of the Ishihara test. His second design was the F2 plate as shown here. Normal trichromats and tritanomalous trichromats see both squares. Normal trichromats describe the yellow-green square as clearer, or more prominent, and tritanomalous trichromats see the blue square more clearly. Tritanopes are intended to see the blue square only. An apparently unintentional bonus is that protans and deutans cannot see the yellow-green square. The F2 plate is therefore a possible all-purpose colour vision screening test and is actually more efficient for detecting red-green defects than it is for detecting tritan defects.Ref: Birch, Jennifer, Diagnosis of defective colour vision, Butterworth-Heinemann, 1993. How Acquired: Donated by Peter Dwyer Date Acquired: Nov 2021 Condition: Excellent Location: Archive room. West wall. Unit 1 Overhead display |