Re: Just How Blind is the Human Race?

From: Dennis M. Hammes (scrawlmark_at_arvig.net)
Date: 06/29/04 

Date: Tue, 29 Jun 2004 07:00:40 GMT

Ian Stirling wrote:
>
> In sci.space.policy Christopher James Huff <cjameshuff@earthlink.net> wrote:
> <snip>
> > Well, we really are practically blind. Our eyes are trichromatic

Monochromatic-with-filters; or "quadrichromatic." But not "tri-."
  11-cis retinal is the /only/ photosensor we've got.
  The three oil filters (assorted among the "cones") reduce the
incident light level considerably, not the sensitivity.
  Same happens putting color filters on a camera or litho
separations.

> > sensors, with limited resolution and only capable of giving very crude
> > estimates of color, lightness, and size. We can not see spectral
>
> Looking at the spectral sensitivities, it's amazing there is
> any vivid contrast between red and green at all.

Heh. Some few people have none whatsoever.
  Monochromatic contrast is /all/ in the filters.

> The two sensors are so similar that the difference in sensitivity
> at any given wavelength between red and green is quite small.

Actually not; we are rather more sensitive to green by at least
e=hf.
  Why subs and planes are set "cockpit red" at night. 

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