http://www.madprime.org/articles/2008/08/13/color-blindness-2-a-world-with-two-hues en-us 40 <p>One of the more profound discoveries I've made regarding color blindness is that there are only two hues in a color blind person's world: blue and yellow. For some reason I thought that the hues between blue and green were still vivid colors, like this:</p> <p><IMG SRC=http://www.madprime.org/article_images/blue_to_green_small.jpg></p> <p>But actually it looks like this (deuteranope simulation):</p> <p><IMG SRC=http://www.madprime.org/article_images/blue_to_green_deut.jpg></p> <p>You can see here that turquoise looks the same as gray/white -- in other words, it looks colorless. There are really only two hues: anything between them looks less intense, more gray.</p> <p>White light is a mixture of all colors - it activates all receptors equally. Because turquoise is right between the two receptors it also activates them equally. The two types of light are providing the same information, it takes a third receptor with a different response to tell the difference. Having a third receptor has a profound effect: all wavelengths become distinct colors, a rainbow of hues is visible. Would adding a fourth receptor have a similarly profound effect? I don't think so -- the spectrum is a linear one-dimensional type of information -- but maybe I'm lacking imagination here.</p> <p>Green traffic lights actually have a bluish tinge to them to distinguish them from the red and yellow lights. Because of this, they actually look white! Here is a digitally merged photo I took, along with a deuteranope simulation:</p> <table> <tr> <td><IMG SRC=http://www.madprime.org/article_images/trafficlight_orig.jpg> </td> <td><IMG SRC=http://www.madprime.org/article_images/trafficlight_deut.jpg> </td></tr> </table> <p>This colorless white/gray effect for hues that hit both receptors evenly is also visible on the other side of the color wheel, in the "unnatural" hues formed by mixing red and blue.</p> <table> <tr><td> <IMG SRC=http://www.madprime.org/article_images/colorwheel.jpg> </td><td> <IMG SRC=http://www.madprime.org/article_images/colorwheel_deuteranope.jpg> </td></tr> </table> <p>Thus the colors potentially confused by red-green color blind fellows goes beyond distinguishing between hues in the red-to-green range. Turquoise and magenta can be confused for gray, and purple can look blue. I'll close here with a series of potential color confusions:</p> <table> <tr><td> <IMG SRC=http://www.madprime.org/article_images/onetwothree_orig.jpg> </td><td> <IMG SRC=http://www.madprime.org/article_images/onetwothree_deut.jpg> </td></tr> </table> Wed, 13 Aug 2008 23:23:00 +0100 urn:uuid:6ad5aadf-d9dd-4b76-87a0-3e55f33fa29a Madeleine Ball http://www.madprime.org/articles/2008/08/13/color-blindness-2-a-world-with-two-hues color miss you so much <a href="http://www.vcsale.com/" rel="nofollow">cheap wow gold</a><br /> Fri, 21 Nov 2008 03:18:30 +0000 urn:uuid:90673aee-f671-486a-8927-4a3994f102de http://www.madprime.org/articles/2008/08/13/color-blindness-2-a-world-with-two-hues#comment-3330