Westcott Color Slide Test for Color Blindness

1. Westcott Color Slide Test forColor Blindness Created for CVCA PhysicsbyDick Heckathorn1 April 2K+2

2. INTRODUCTORY Since COLOR-BLINDNESS absolutely disqualifies a personfor some vocations, as those connected with the railroads, the navy, color-photography or painting,

3. this defect is probably not receiving the attention it should. On the other hand it is an interesting fact that many of the famous engravers have been color blind.

4. Except in cases of accident, color-blindness dates from birth and is due to a defect in the retina of the eye which cannot be remedied.

5. Color-blindness as usually occurring may be divided into two general classes -- red-blind and green-blind -- depending on which color is absent in the color sense, and it sometimes happens that both these colors are absent.

6. A third and rare form is the violet-blind. Of the human race about 4% of males and about one-fourth of 1% of females are said to be blind to red, or green, or to both.

7. Attention was brought forcibly to the danger of color-blindness among railway employees by a serious accident in Sweden in 1875 due to this defect.

13. DIRECTIONS A Westcott slide will be used for testing whether you are color-blind or not.

15. Take out a pencil and a piece of paper. Once your instructor begins to give directions, NO questions or discussion will be allowed until the test is finished. There is to be NO talking from now on.

16. TEST A On the paper write the number of the sample color(s) that you think are similar to (Green) Color A.

17. You will find very few, if any samples exactly like Color A. You are to include in this list all greens whether tending toward the yellow, or toward the blue.

18. There are many samples of color on the slide which should not be included in any of the lists asked for.

19. Your instructor will wait until he senses all are finished.

21. How many of these numbers do you have on your list? 2 5 16 24 26 28 37 39

22. If you are color-blind, whether to red or green, you will include with the greens one or more grays, browns or roses, and it is not uncommon for you to include as many as twenty numbers in this list.

23. The presence of any of the above among the greens betrays at once that you have a defective color sense for either red or green. Now, let’s proceed with test B.

24. TEST B As before, on the paper write the number of the sample color(s) that you think are similar to Rose (Color B).

26. How many of these numbers do you have on your list? 1 13 23 36 40

27. The red-blind selects indifferently roses and blues, while the green-blind adds greens and grays. The tendency of the color-blind being always to select deeper colors.

28. TEST C This test is to confirm the results of tests A and B. As before, on the paper write the number of the sample color(s) that you think are similar to Red (Color C).

30. How many of these numbers do you have on your list? 3 21 25 27 38

31. The red-blind will select besides the reds, greens and browns darker than the red. The green-blind will add greens and browns lighter than the red.

32. Only the more marked cases of color-blindness are likely to show their defect in this test.