Re: Communicating colour to aliens

There is no such thing as non-perceptual color.  Color does not occur until
the light reaches the retina and the generated neutral stimulus is
interpreted by the brain.  Reflectance or transmittance is a property of the
material and is the same whether a human observer is present or not.  A
banana will absorb short-wavelength light and reflect all other wavelengths
but only trichromatic observers will be able to call that stimulus "yellow".

Danny Rich

"Ben Newsam" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Danny Rich <[EMAIL PROTECTED]> writes, despite their Organization
> header saying 'Optimum Online'
> >The spectral data describe the object - this is true but the spectral
> >data do not describe the color.
>
> Not the perceptual colour perhaps, but the absolute colour. As long as
> there is a component of every visible wavelength in an illuminant, the
> spectral reflectance or transmission values (expressed as percentages)
> are going to be the same no matter what illuminant is used.
> -- 
> Ben