GRGR meta / 1,3 various

[Michael J. Hußmann]

Glenn Scheper (glenn_scheper at earthlink.net) wrote:

> When asked why he skipped it, and would
> other people skip it, he said it depend what you are doing and
> referred these names to a "color wheel". Purple is when violet
> tends toward blue.
>
> Here is a picture of a rainbow against a dark background,
> and you can see that there is no violet in it:
> http://www.free-picture-graphic.org.uk/rainbow.htm

For all the other colours, there is a wavelength of light that will
produce the sensation of that colour, only for purple, there isn't.
There's no purple in the colour spectrum. Only because human colour
vision is metameric, i.e. based on a small number of primary colours and
their mixture, our brain bends the linear spectrum to form a colour ring
or wheel, with violet (the shortest wavelength visible) gradually
blending into red (the longest wavelength visible). Where the ends meet,
we see purple.

> in green far better than other colors. I said, What about
> the color of flesh? Ever put the spectrophotometer on
> your own skin? He suggests it is near the center of the
> color wheel, a complex mixture of colors, towards orange.

Someone from Fujifilm once explained to me how we all share the same skin
colour in terms of hue (basically it's the colour of blood); it's only
the saturation and brightness values that differ.

- Michael


Michael J. Hußmann

E-mail: michael at michael-hussmann.de
WWW (personal): http://michael-hussmann.de
WWW (professional): http://digicam-experts.de