Re: The color purple
Re: The color purple
- Subject: Re: The color purple
- From: Liz Day <email@hidden>
- Date: Tue, 28 Mar 2006 21:20:05 -0500
>The error in this companies presentation is the fact that they represent
>purple as a spectral color at the blue end of the spectrum. Their
>"purple" is made up of the following RGB values:
>
>99R 57G 186B
Ah hah. I was always taught that the reason some purples and blues did
not register properly on film was the films' ability to respond to UV light
which the eye did not see. This must be something other than that.
>This is a non spectral color in the magenta family. This means that it
>is a color that cannot be produced by a single spectral frequency. This
>is a color that is an illusion in the brain when you stimulate the long
>wave cone and the short wavelength cone with very little stimulation of
>the mid wavelength cone. I have always used this as an illustration of
>how the eye has only three overlapping channels and is not good at
>discriminating multiple frequencies of light..... if you mix
>the light from a red and blue LED, the eye sees one color which is
>magenta. It is like saying that when you play a cord of spectral
>frequencies your eye only sees one note.
I think this is called "trichromatic" vision. An ornithologist explained
this to me, because he was trying to find out whether birds have
tetrachromatic vision (i.e., does their brain blend the info from their UV
cone in with all the rest, or see it separately). I have not heard what
his results were yet.
>Now back to the tribecalabs...I think they are showing a short coming in
>the RAW to color space conversion rather that the fact that digital
>cameras are blind to purple. It may also be a problem with the LCD in
>the camera. For their claims to be true, the camera would have to be
>blind to red, green, and blue as show from the data values above.
Sounds pretty dubious.
Aren't you glad that none of your clients are birds, so printing only deals
with CMYK and not UV?
(Or does it?)
:-)
Liz Day
Indianapolis IN USA
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