Crammer's Comments

(did I double post?)

"(your recepters are for red, green, and blue)"

Kind of. The receptors are for short, medium, and long wavelengths.

Their ranges overlap a bit. Wavelengths that trigger the short receptors are translated as blue. The medium green, and short blue (at least as far as I can tell, depending on how you read the various descriptions), but as the receptors respond to the same light, the relative strengths of the signal (I think) are translated into the varying intermediate colors. Long (red) and medium (green) receptors firing at the same time are interpreted as yellow, for example. We can't "see" a reddish green, because red+green (long + medium) is already perceived as yellow. We *already* have a color that describes that combination.

We perceive colors that can be produced by the full range of physically possible overlapping wavelengths within the visible light spectrum. Take Magenta: there's no single wavelength that can trigger both the long and short receptors while NOT stimulating the middle receptors. But since they can be simultaneously stimulated by *separate* wavelengths, we have the "extraspectral" color Magenta - which you will not find in a rainbow, or in an illustration of the visible light spectrum. Wrapping a spectrum diagram around in a circle so the long red end overlaps with the short blue end is how we get a diagram - the color wheel - that shows all the colors we can see: all the possible combinations of length/receptor overlap that can be triggered by actual light sources.

Take a cup of hot water and mix it with cold, you get warm. We have a sensation mapped onto that combination of degrees of heat. Somehow these experiments are stimulating some kind of response where the brain isn't perceiving warm, its like the subjects are their hands in hot and cold at the same time. It doesn't make any sense physically, but the receptors are being stimulated that way nonetheless, and perceiving something new and completely imaginary, that is not mapped directly to anything in the real world. Or, I could be full of it.
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"(your recepters are for red, green, and blue)"

Kind of. The receptors are for short, medium, and long wavelengths.

Their ranges overlap a bit. Wavelengths that trigger the short receptors are translated as blue. The medium green, and short blue (at least as far as I can tell, depending on how you read the various descriptions), but as the receptors respond to the same light, the relative strengths of the signal (I think) are translated into the varying intermediate colors. Long (red) and medium (green) receptors firing at the same time are interpreted as yellow, for example. We can't "see" a reddish green, because red+green (long + medium) is already perceived as yellow. We *already* have a color that describes that combination.

We perceive colors that can be produced by the full range of physically possible overlapping wavelengths within the visible light spectrum. Take Magenta: there's no single wavelength that can trigger both the long and short receptors while NOT stimulating the middle receptors. But since they can be simultaneously stimulated by *separate* wavelengths, we have the "extraspectral" color Magenta - which you will not find in a rainbow, or in an illustration of the visible light spectrum. Wrapping a spectrum diagram around in a circle so the long red end overlaps with the short blue end is how we get a diagram - the color wheel - that shows all the colors we can see: all the possible combinations of length/receptor overlap that can be triggered by actual light sources.

Take a cup of hot water and mix it with cold, you get warm. We have a sensation mapped onto that combination of degrees of heat. Somehow these experiments are stimulating some kind of response where the brain isn't perceiving warm, its like the subjects are their hands in hot and cold at the same time. It doesn't make any sense physically, but the receptors are being stimulated that way nonetheless, and perceiving something new and completely imaginary, that is not mapped directly to anything in the real world. Or, I could be full of it.
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Philf: Of course I realize the context is historicity (which "anonymous coward" points out may be suspect due to the inclusion of the signal beacons those guys are waving around up at the front of the rafts) - but I busted out of that context and commented on the painting's style. I included courtesy scare quotes so as not to offend, and even included links to images as a reference to fairly objectively similar styles, which could also, with the same dose of charity, be called "realistic". I mean, have you ever *seen* reality? It doesn't look like that.

I'll also add to anonymous coward's comments, and point out that the guy with the pole, image right, is wearing a digital watch, and the guy four rows back, image left, is clearly texting.
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Maybe someone else can comment on the artist's goals and failures. I was commenting on the painting's style, which is Kinkadesque, and the post's title, which calls it a "realistic", which it is not.
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"Realistic" in the way a Thomas Kinkade painting is "realistic":
https://www.google.com/search?q=thomas+kinkade&hl=en&safe=off&prmd=imvns&source=lnms&tbm=isch
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"We are getting nearer to the “can we do it?” part, but the question “should we do it?” remains."

That's the easy part. The answer is "Yes!"

Then do a Mastodon - much cooler than a Mammoth.

Then a wooly rhino and sabertooth cat. All the cool ones.
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