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cliche · 11-13-2003, 07:31 AM

Eldaire - colour is not measurable. Wavelength, yes. Mixture of wavelengths, yes. But colour - no. Your wavelength example hits a flaw with - for example - a television. The TV shows a picture of an orange. I can see it from the other side of the room; it's orange. But your "wavelength detector" can only detect the outputs of the three primary colours produced by the TV. There's no orange wavelength there (as there might be were there a real orange); just a mixture of red, blue, green which fools our eyes into seeing orange.

If you want to say the TV orange "isn't really orange" then substitute any two things which have the same subjective colour, but have different sets of wavelengths.

The ideas of "is object X the same colour as object Y" suggests that colours are much more about us than the objects themselves - a dichromat ("colour-blind" person) can't make some of the distinctions we do; there are people (anomalous trichromats) who have a slightly different red sensitivity, who will make different distinctions to the rest of us; and there are even people (women, as mentioned earlier) who have both types of red sensitivity and are capable of making more distinctions than anyone else! Animals also have different sensitivities: different ranges, and there are some birds use 4 or more colours to see...

Complicated, huh?

11-13-2003, 07:31 AM	#42 (permalink)
cliche Rookie Location: Oxford, UK	Eldaire - colour is not measurable. Wavelength, yes. Mixture of wavelengths, yes. But colour - no. Your wavelength example hits a flaw with - for example - a television. The TV shows a picture of an orange. I can see it from the other side of the room; it's orange. But your "wavelength detector" can only detect the outputs of the three primary colours produced by the TV. There's no orange wavelength there (as there might be were there a real orange); just a mixture of red, blue, green which fools our eyes into seeing orange. If you want to say the TV orange "isn't really orange" then substitute any two things which have the same subjective colour, but have different sets of wavelengths. The ideas of "is object X the same colour as object Y" suggests that colours are much more about us than the objects themselves - a dichromat ("colour-blind" person) can't make some of the distinctions we do; there are people (anomalous trichromats) who have a slightly different red sensitivity, who will make different distinctions to the rest of us; and there are even people (women, as mentioned earlier) who have both types of red sensitivity and are capable of making more distinctions than anyone else! Animals also have different sensitivities: different ranges, and there are some birds use 4 or more colours to see... Complicated, huh? __________________ I can't understand why people are frightened of new ideas. I'm frightened of the old ones. -- John Cage (1912 - 1992)