Re: [Phys-l] perception of variations in hue

["John Clement" <clement@hal-pc.org>]

If you look at the box with the magnified pixels you see a similar effect at
the pixel boundaries.  There are lines at the boundaries, and the color
shades across the squares.  I assume each square has exactly even luminance.
Or could this me my monitor?  I tend to doubt it because of the way modern
digital monitors work.

The suppression of cones is, I think, done for each color separately.  The
luminance is of course not a separate parameter as the male eye only sees 3
colors.  So since both colors have a kink, you will see a change in
luminance.  About 20%? of females can see 4 colors and have color perception
which is much more acute than normal.  This as I have surmised, is due to
the fact that one of the colors (probably green) can have 2 different
genetically determined filters.  I found a paper that agrees with my
deduction.  I wonder if they see exactly the same thing.

The division of color into chroma, luminance, and saturation is only an
engineering/math model which does not actually correspond to the way that we
see.  I was surprised to see that in 2009 there was a paper saying that the
usual engineering color theory is not adequate because surround colors
change color perception.  Well duh, Land showed in the late 60s that color
perception did not follow the usual engineering model.  The 2009 paper was
being touted as a new development in cognitive science, even though this has
been known for a very long time.

Howard Hughes has a fairly good web book on perception at
http://www.hhmi.org/senses/
It includes a good section on color constancy.

John M. Clement
Houston, TX

> On 02/09/2011 11:48 AM, Stefan Jeglinski wrote:
>
> > I'm not sure if this is my eyes, or my [LED] monitor.
>
> That's a good question.
>
> For those of you who may be wondering whether you are seeing
> rays (or lack thereof) due to some peculiarity in your display
> hardware, I just now added some figures that show the same data,
> just rotated 10 degrees. The pattern we wish to discuss should
> be rotated; any display artifacts should remain unrotated.
>
>    http://www.av8n.com/imaging/disk-rays-no-rays.htm
> _______________________________________________
> Forum for Physics Educators
> Phys-l@carnot.physics.buffalo.edu
> https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l