Friday, July 08, 2011

Seeing things

What number(s) do you see here? This is the third image in the Ishihara Color Blindness Test, designed so that those with partial or total color
blindness make out different numbers than those with normal vision, and sometimes can discern none at all. Those with normal vision see a 29 here, those with red-green deficiencies see 70; those with total color blindness can make out no numbers at all. How about the one below?
This one (#14) is the first in which only those with color blindness see a number - 5 - while others can make out nothing at all.

No comments: