colors in E-prime

[Jeff Szuhay]

>Did anybody make any experiments with colored objects?
>I need to present objects with four different colors, but I'm just
>unable to find/create four colors which would be equivalent on all
>characteristics  (luminance, brightness, etc.) and still be readily
>distinguishable from each other. Besides, they should be easily
>perceived even when presented at a rate of 100 msec.
>The best I could find is white, yellow, black and blue on a grey
>background, but honestly only white and yellow are good. Black and blue
>are less prominent, because darker.
>If anybody had colors in their experiments, I would really appreciate
>it if you could tell me which colors you used.

Be aware that all colors are not equal to the human eye.
About 55% of human eye color cells (cones) detect green
About 40% of them detect red, and
about 5% of them detect blue.

However, on a computer screen red, blue and green are equally represented
to give the widest range of colors possible (regardless how the human eye
detects them).

You could try for your 3 colors:
   pure red, pure green, and pure blue
and then use white (which will be more intense since it is all three
of them) or
a less intense grey (each of red, green and blue at 1/3 their "pure" values).

Jeff Sz.
--

    Jeff Szuhay            <mailto:jeff.szuhay at pstnet.com>
    Lead Macintosh Engineer      voice: 412-271-5040 x 227
    Psychology Software Tools     <http://www.pstnet.com/>