Early Morning Ponderings : The Nature of Colour

[GuyOnTilt]

So once again I woke up early, and once again that led to me feeling fresher and having more mental energy in me. [img]/images/graemlins/smile.gif[/img]

So a thought just popped into my head re: colour. We all have learned thanks to Locke that colour is not a primary quality of any object, but rather a secondary characteristic that is more a product of it's primary qualities. What I'm curious about is whether these specific things we call "colours" exist out there in nature, or are they more a construct of our brains? I'm having a hard time phrasing the exact question I'm wonder about, but in essence, does colour really "exist" in the universe? I suppose this might end up pertaining to the nature of light more than anything else, something which I know relatively nothing about. My question might be better rephrased as, "Is colour an intrinsic property of light," but I'm not sure.

GoT

Colour is your brain's way of telling you that the light you're seeing is of a particular wavelength (or combination of wavelengths).

To see an object in a certain colour means that it reflects (or emits) that wavelength (or wavelengths) of light. Which wavelengths it reflects depends on how the particular structure of its atoms and electrons interact with photons of light.

[gamblore99]

[ QUOTE ]
Colour is your brain's way of telling you that the light you're seeing is of a particular wavelength (or combination of wavelengths).

To see an object in a certain colour means that it reflects (or emits) that wavelength (or wavelengths) of light. Which wavelengths it reflects depends on how the particular structure of its atoms and electrons interact with photons of light.

[/ QUOTE ]

I would further add that how we percieve a colour of an object depends on its background. Also negative afterimages, can make something appear to be a different colour by bleaching the colour receptors.

Here is a link to a quick afterimage experiment

afterimage

So in conclusion, objects emit certain wavelengths, how we interpret them determines what colour we see them. This interpretation can be changed depending on a variety of things. Colour is in the mind.

It depends slightly on the background. No matter what color you superimpose pink on, you won't see it as green, but the shading may change slightly. So the color is still independent of the brain, bar some small corrections made by our visual processing software and hardware.

Also note that bleaching of pigments etc doesn't mean that color resides in the mind. That's like putting a magnet on my download cable, corrupting the data stream, and then claiming that the data doesn't exist independent of my computer (or resided there).

[GuyOnTilt]

[ QUOTE ]
Colour is your brain's way of telling you that the light you're seeing is of a particular wavelength (or combination of wavelengths).

To see an object in a certain colour means that it reflects (or emits) that wavelength (or wavelengths) of light. Which wavelengths it reflects depends on how the particular structure of its atoms and electrons interact with photons of light.

[/ QUOTE ]
Right. I was taught all of this in middle school, but things I've come across sporatically make me think it might not be that simplistic. I'm not positive on any of this since I haven't studied it in depth, but my understand is that what I perceive as an object's "colour" is not just one wavelength being being reflected, but a range or spectrum of wavelengths, and my eye or brain's tendency to interpret that as one particular colour is completely personal and can and will vary greatly depending on species or even individual entities within a species (i.e. biological makeup). I had come across this before but didn't really think anything of it, but early this morning I happened upon this article from An Anthropology on Mars:

"In 1957, ninety-odd years after Maxwell's famous demonstration, Edwin Land - not merely the inventor of the instant Land camera and Polaroid, but an experimenter and theorizer of genius - provided a photographic demonstration of color perception even more startling. Unlike Maxwell, he made only two black-and-white images (using a split-beam camera so they could be taken at the same time from the same viewpoint, through the same lens) and superimposed these on a screen with a double lens projector. He used two filters to make the images: one passing longer wavelengths (a red filter), the other passing shorter wavelengths (a green filter). The first image was then projected through a red filter, the second with ordinary white light, unfiltered. One might expect that this would produce just an over all pale-pink image, but something `impossible' happened instead. The photograph of a young woman appeared instantly in full color - `blonde hair, pale blue eyes, red coat, bluegreen collar, and strikingly natural flesh tones,' as Land later described it. Where did these colors come from, and how were they made? They did not seem to be `in' the photographs or in the iluminants themselves. These demonstrations, overwhelming in their simplicity and impact were color `illusions' in Goethe's sense, but illusions that demonstrated a neurological truth - that colors are not `out there' in the world, nor (as classical thery held) an automatic correlate of wavelength, but, rather, are constructed by the brain."

This got me thinking and I did some very brief research online, but I don't know enough about these areas to draw any real conclusions.

GoT

[ QUOTE ]
blonde hair, pale blue eyes, red coat, bluegreen collar, and strikingly natural flesh tones,' as Land later described it. Where did these colors come from, and how were they made? They did not seem to be `in' the photographs or in the iluminants themselves.

[/ QUOTE ]
Gee, no one saw a brunette or redhead with hazel or brown eyes (or even dark blue)? I think something else may be going on here [img]/images/graemlins/wink.gif[/img]

[gamblore99]

Phil, I really don't like your computer analogy. Negative afterimages do not involve any outside effects on the eye. They are caused by just looking at one colour for a short time. Second the changes caused by the background can be very dramatic, more than a change in shade. Our mind percieves colour based on a colour contrast mechanism. I have to study now, and I don't know the details off the top of my head, but I will bust out my textbook and get some more in depth explanations for this thread later tonight.

[Bork]

There are no colors if there are no brains to detect and interpret the light.

Like with any sense, the actual sensations like redness, the smell of pumpkin pie, the taste of chocolate, the sound of an orchestra, and the soft feel of a boob are all purely psychological phenomena.

This is not to say that there are no actual physical soft boobs out there. Its just the soft sensation would not exist without a brain to detect and interpret it. It is the same for color. Color is the sensation caused by light in us.

[carlo]

"Color is the deeds and sufferings of light"--Goethe.

carlo

I've heard that due to some mutation certain people can see a wider range of colors (within the same spectrum). I think the general idea is that instead of seeing 7 colors in a rainbow they see 10, or something along those lines.

I don't remember exactly where I heard this, but is it true? And if so, how does it work?

I was also under the impression that color sensation in human beings is a bit "sloppy." That the way our nervous system responds to different wavelengths of light isn't always accurate or evenly distributed.