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Vision and Color


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I have a question about the perception of color and have a small thought experiment on it.

 

Lets imagine that we take a group of 4 children that have not yet learned colors.

 

We teach 2 of them that everything they see that we normally call "black" is actually "white". And all that is "white" is "black". The other two, we teach normally.

 

 

Wouldn't the first two children never really know in noone ever told them that what they see is not what everyone else supposively sees?

 

So, what my real question is, isn't this how everyone learns how to distinguish colors. Someone tells us at any early age that a particular color is say "red", and now for the rest of our lives, anything that looks like that is "red".

 

How do we really know that everyones spectrum is the same?

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because everyone's brains work in the same way and the laws of physics apply to everyone equally. you can change the words, but it doesn't change the physics. if you teach a child that down is up and up is down, and they won't suddenly plummet off into outer space because you told them the wrong words.

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What you see as green, I could see as purple.

 

But since we're taught the words 'green' and 'purple' with reference to the colours (THEYRE JUST LABLES) everyone thinks 'green' is the colour they see when they look at a 'green' object.

 

This could explain people's fashion sense.

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Originally posted by MrL_JaKiri

What you see as green, I could see as purple.

 

But since we're taught the words 'green' and 'purple' with reference to the colours (THEYRE JUST LABLES) everyone thinks 'green' is the colour they see when they look at a 'green' object.

 

This could explain people's fashion sense.

 

This is exactly what I used to think long ago, but I'm not sure anymore. There are still many things about color that we still all agree upon ..

 

One such a thing is the colors most people percieve as matching. There is also how most of us agree that two colors are "close" to each other.

 

Don't you agree that green is more similar to blue that red?

 

This could also be attributed to the physical properties of these colors, but if I was to immagine in my head the colors green and blue, I would still think they are close to each other.

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Originally posted by Sayonara³

Funny, because red is a component of green and blue isn't.

 

Or have hex values clouded my memory of colour physics? :-(

 

yes and no. the colours you see can be entirely different to the colours that are. for example a given red might be a pure frequency, or it may be a mixture of colours which your eye interprets as red, since your eye effectively sees in three colours (though the "colours" are quite broad spectra)

The brain interprets a given colour by the relative intensities of excitement of the three colour cones in the eye. so a given colour may be seen by either: a pure frequency which excites the red cone by "x" amount and the blue cone by "y" amount, or two colours which excite the relevant cones by the same amount. The colours would look indistinguishable to you, but stick them in a spectrometer and they would look totally different. If I recall correctly, there was an experiment carried out where people were fooled into seeing colours, when all they were really looking at were a couple of yellow spectral lines.

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I know how eyes work.

 

I'm assuming that when Ahmad says green, he means 00FF00, and when he says red, he means FF0000.

 

Obviously there's room for interpretation and plenty of scope for different possibilities though.

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Originally posted by Sayonara³

I know how eyes work.

 

I'm assuming that when Ahmad says green, he means 00FF00, and when he says red, he means FF0000.

 

Obviously there's room for interpretation and plenty of scope for different possibilities though.

 

that was my point, he could equally be seeing 540 nm light when he sees green and 630nm light when he sees red... purple could be pure 420 nm light or something, or some XX00XX type thing, which would be a mix of frequencies

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Originally posted by Sayonara³

That was kind of what I was talking about.

 

Maybe red and green weren't the best example to use.

 

maybe. Also, looking at it from the pov of the human eye is bad because of the way our brains are wired. there are lots of tricks that the brain uses in order to improve contrast, for example of one cell on the retina is excited, the signals from surrounding cells will be supressed, leading to better point and edge detection. The same also applies to colours as well... If you see red, then the signals from the surrounding green-detecting cells will be supressed - and these sorts of effects could lead in part to thinking that green is more different from red than blue is, because you never see the colours in that kind of conjunction with one another.

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Originally posted by Sayonara³

Funny, because red is a component of green and blue isn't.

 

Or have hex values clouded my memory of colour physics? :-(

I think they must have. Blue is a component of green, red isn't. Green = yellow + blue. As far as the retina goes, we have 3 types of cone cells, basically red, yellow and green (except women. PM studies have shown some females have 5 types of cone cells).

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Green is the result of mixing the subtractive primary colours blue and yellow. However, green in an additive primary colour in its own right and not the result of mixing. Here's how it goes:

 

The additive primaries (light) are Red, Green and Blue.

 

Red + Green = Yellow

Green + Blue = Cyan

Red + Blue = Magenta

 

Red + Green + Blue = White.

 

Yellow, Cyan and Magenta are the subtractive primaries (pigment).

 

Yellow + Cyan = Green

Yellow + Magenta = Red

Cyan + Magenta = Blue

 

Yellow + Cyan + Magenta = (Compound) Black

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  • 20 years later...
On 6/12/2003 at 1:29 PM, BPHgravity said:

I have a question about the perception of color and have a small thought experiment on it.

 

Lets imagine that we take a group of 4 children that have not yet learned colors.

 

We teach 2 of them that everything they see that we normally call "black" is actually "white". And all that is "white" is "black". The other two, we teach normally.

 

 

Wouldn't the first two children never really know in noone ever told them that what they see is not what everyone else supposively sees?

 

So, what my real question is, isn't this how everyone learns how to distinguish colors. Someone tells us at any early age that a particular color is say "red", and now for the rest of our lives, anything that looks like that is "red".

 

How do we really know that everyones spectrum is the same?

Good experiment

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