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Author Topic: Magenta doesn't exist?
Shmuel
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quote:
Originally posted by Lisa:
Me, too. I read through that article, and I still don't get what's wrong with RYB.

Nothing's wrong with it, really; it's just a question of additive colors vs. subtractive colors. For printing, cyan/magenta/yellow is essentially blue/red/yellow, just slightly different shades thereof than one finds in kindergarten construction paper. [Smile]
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The Pixiest
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I had a cow-orker one time tell me to plug something into "the grey box." I looked for the damn thing for a half an hour before I gave up and made him come upstairs and point it out.

quote:

So there you have it: All men are colorblind.

I said "That's not grey, that's silver."

He objected.

I then went and got everyone in the building (it was a relatively small office) and asked them what colour it was. Every man said "Grey" every woman said "Silver."

It's comforting, after all these years, to have scientific proof that I was right.

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advice for robots
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I have a terrible memory for colors. I usually can't remember what color someone was wearing, even if it was fairly bright. I am terrible trying to add color to any drawings I do. However, I think I see colors just fine.
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mr_porteiro_head
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Grey and silver are the exact same color, but with different reflective properties.
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rivka
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quote:
Originally posted by Shmuel:
For printing, cyan/magenta/yellow is essentially blue/red/yellow, just slightly different shades thereof than one finds in kindergarten construction paper. [Smile]

Pfft. Who combines construction paper colors?

FINGER PAINTS! [Big Grin]

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Mike
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So a mirror is grey? I'd call it colorless.

I remember having an argument with my sister when I was about 8 about the color of one of my textbooks. I still think I was right. But I guess I must have been wrong, huh. [Wink]

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Jon Boy
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quote:
Originally posted by rivka:
Perhaps so. But guess what they're teaching in kindergartens across the nation, right at this very moment?

Guess what they taught in the color theory class I took in college? [Grumble]

quote:
Originally posted by Shmuel:
Nothing's wrong with it, really; it's just a question of additive colors vs. subtractive colors. For printing, cyan/magenta/yellow is essentially blue/red/yellow, just slightly different shades thereof than one finds in kindergarten construction paper.

Not exactly. The difference between RYB and CMY is not additive versus subtractive, but two different subtractive systems, one of which does not work as well. You cannot make good greens with blue plus yellow, and you cannot make good purples with red plus blue. It's akin to trying to make yellow out of orange and green.

I should note, though, that the cyan and magenta that printers use are not the same as the cyan and magenta that you get by mixing blue and green or blue and red light. They're a little closer to red and blue, respectively, which means that they don't produce very vivid purples and greens. Four-color process printing has a much smaller gamut than computer monitors do.

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Shmuel
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quote:
Originally posted by rivka:
Pfft. Who combines construction paper colors?

FINGER PAINTS! [Big Grin]

A good point. [Smile]

quote:
Originally posted by Jon Boy:
Not exactly. The difference between RYB and CMY is not additive versus subtractive, but two different subtractive systems, one of which does not work as well.

I was referring to RYB/CMY vs. RGB.

With that said, I stand by the contention that M is just a specific shade of R and C is a specific shade of B, making the terms essentially the same for those who don't work in relevant fields... and certainly close enough for primary school. [Smile]

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Pegasus
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quote:
Originally posted by Jon Boy:
Four-color process printing has a much smaller gamut than computer monitors do.

Ain't that the truth...

In my day job it is common for people to bring us files to be printed that were setup in the RGB colorspace instead of CMYK. It's typically because they just don't know the difference or because they usually make graphics for the web.


Some 4-color process printers are actually 6 or 7 colors with the addition of light cyan, light Magenta, etc. Still your basic subtractive colors, Although I did see a printer advertised as having RGB inks... chyeah... right....

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rivka
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quote:
Originally posted by Shmuel:
With that said, I stand by the contention that M is just a specific shade of R and C is a specific shade of B

Definitely not. (And you know what Rabbit said! [Wink] ) Magenta is a red/blue, not a red; cyan is a blue/green, not a blue.
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Jon Boy
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Agreed. And it's not just an issue of terms, but of the effect you get when you mix those particular pigments.

Pegasus: I've heard about that kind of thing a lot. The prepress team at my last job said that the creative department always sent them stuff in RGB, and no matter how many times prepress tried to tell them what the problem was and teach them how to fix it, they never caught on. [Roll Eyes]

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rivka
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We have an outside person create our color ads. But how would I know which colorspace I was using, in, say, Publisher?
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scifibum
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Grey IS colorless.
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rivka
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No. Grey is not white.
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lobo
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I agree with Rabbit about women and colors. There has to be a reason that my wife has 5 different (to me identical) pairs of red shoes...
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mr_porteiro_head
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quote:
Originally posted by Mike:
So a mirror is grey?

I'd say no, and it's not silver-colored either.
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rivka
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Huh. What color is it?
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mr_porteiro_head
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It's not. It's a mirror. [Razz]
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rivka
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. . . um. And mirrors are outside the definitions of color?
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Jon Boy
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What color is it when it's not reflecting anything? [Razz] Or maybe the better question is, what color does it add to reflections? Most of the difference in color between the original and the reflection is probably going to come from the glass, though.

As for your Publisher question, I don't know because I don't use Publisher. In InDesign CS it's under Edit > Color Settings.

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scifibum
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quote:
Originally posted by rivka:
No. Grey is not white.

Grey is white. Just less of it.
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scifibum
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quote:
Originally posted by Jon Boy:
What color is it when it's not reflecting anything? [Razz] Or maybe the better question is, what color does it add to reflections? Most of the difference in color between the original and the reflection is probably going to come from the glass, though.

As for your Publisher question, I don't know because I don't use Publisher. In InDesign CS it's under Edit > Color Settings.

It doesn't add color, it subtracts it. You get less back than you shined at it.

Aside from the color of the glass (which is usually minimal).

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Jon Boy
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Yeah, but when you mix yellow paint and red paint, you say that you added one to the other, not that you subtracted the complement of one from the other. [Razz]
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rivka
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quote:
Originally posted by scifibum:
quote:
Originally posted by rivka:
No. Grey is not white.

Grey is white. Just less of it.
O_o

No.

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mr_porteiro_head
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quote:
What color is it when it's not reflecting anything? [Razz]
*tuns mirror around and looks at the back side*

Grey.

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scifibum
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quote:
Originally posted by rivka:
quote:
Originally posted by scifibum:
quote:
Originally posted by rivka:
No. Grey is not white.

Grey is white. Just less of it.
O_o

No.

Yes [Razz]
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The Rabbit
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quote:
Originally posted by The Rabbit:
The bottom line men is this, if you are in an argument with a woman about color, acquiesce. Its very likely that she can seen colors better than you.

Quoted because some of the men here seem not only to be colorblind but also to be slow learners.
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kmbboots
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quote:
Muriel Blandings: I want it to be a soft green, not as blue-green as a robin's egg, but not as yellow-green as daffodil buds. Now, the only sample I could get is a little too yellow, but don't let whoever does it go to the other extreme and get it too blue. It should just be a sort of grayish-yellow-green. Now, the dining room. I'd like yellow. Not just yellow; a very gay yellow. Something bright and sunshine-y. I tell you, Mr. PeDelford, if you'll send one of your men to the grocer for a pound of their best butter, and match that exactly, you can't go wrong! Now, this is the paper we're going to use in the hall. It's flowered, but I don't want the ceiling to match any of the colors of the flowers. There's some little dots in the background, and it's these dots I want you to match. Not the little greenish dot near the hollyhock leaf, but the little bluish dot between the rosebud and the delphinium blossom. Is that clear? Now the kitchen is to be white. Not a cold, antiseptic hospital white. A little warmer, but still, not to suggest any other color but white. Now for the powder room - in here - I want you to match this thread, and don't lose it. It's the only spool I have and I had an awful time finding it! As you can see, it's practically an apple red. Somewhere between a healthy winesap and an unripened Jonathan. Oh, excuse me...
Mr. PeDelford: You got that Charlie?
Charlie, Painter: Red, green, blue, yellow, white.
Mr. PeDelford: Check.


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Jon Boy
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quote:
Originally posted by The Rabbit:
quote:
Originally posted by The Rabbit:
The bottom line men is this, if you are in an argument with a woman about color, acquiesce. Its very likely that she can seen colors better than you.

Quoted because some of the men here seem not only to be colorblind but also to be slow learners.
Yeah, and some of us men can discern colors better than many women. Just because men in general may not notice or care about colors as much as women doesn't mean they're colorblind or slow learners.
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Noemon
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quote:
Originally posted by The Rabbit:
quote:
Originally posted by The Rabbit:
The bottom line men is this, if you are in an argument with a woman about color, acquiesce. Its very likely that she can seen colors better than you.

Quoted because some of the men here seem not only to be colorblind but also to be slow learners.
Nope! Not condescending enough. Try it again, but this time, I want to be able to see the contempt physically dripping down my screen (in whatever color you deem most appropriate, of course).
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Jon Boy
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Not that the particular color will make any difference to you, Noemon; you won't be able to tell what it is anyway. We all know that men see in shades of grey, or, if they're lucky, in EGA mode, like old computer monitors.
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scifibum
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quote:
Originally posted by Noemon:
quote:
Originally posted by The Rabbit:
quote:
Originally posted by The Rabbit:
The bottom line men is this, if you are in an argument with a woman about color, acquiesce. Its very likely that she can seen colors better than you.

Quoted because some of the men here seem not only to be colorblind but also to be slow learners.
Nope! Not condescending enough. Try it again, but this time, I want to be able to see the contempt physically dripping down my screen (in whatever color you deem most appropriate, of course).
I think Rabbit is going for the same brand of cuteness you get from statements about how husbands are counted in the number of "kids" the wife looks after.
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Mike
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"Cute".
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The Rabbit
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quote:
Originally posted by Jon Boy:
quote:
Originally posted by The Rabbit:
quote:
Originally posted by The Rabbit:
The bottom line men is this, if you are in an argument with a woman about color, acquiesce. Its very likely that she can seen colors better than you.

Quoted because some of the men here seem not only to be colorblind but also to be slow learners.
Yeah, and some of us men can discern colors better than many women. Just because men in general may not notice or care about colors as much as women doesn't mean they're colorblind or slow learners.
Sorry, I meant to be funny not insulting and certainly wasn't referring to you. I found it amusing that even after I'd presented evidence that women may be physiologically capable of discerning differences in color that men are not, some men were continuing to argue that color differences some women perceive as significant really don't exist.

By definition, men have only one X chromosome and women have two. Since the genes for red and green cones are on the X chromosome there is a real physiological difference in color perception between all normal XY males and all XX females. Certainly there is more to color perception than just the cones in the eye so it is debatable how much that physiological difference contributes to peoples ability to 'discern' color. However that physiological difference is a true gender linked difference that isn't really debatable anymore than its debatable whether men have testicles and women have ovaries. It a true binary difference between men and women and not a trait like "nurturing" where there is wide variability within each gender so that some many are much better nurturers than many women.

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scifibum
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You said that women might have more types of cones, but I don't see how this would necessarily change perception. If they have normal red cones and colorblind red cones, what would the colorblind cones add to the perception? It seems likely that adding less red-sensitive cones to more red-sensitive cones wouldn't improve the overall perception; in fact allowing for the same density of cones it seems like it would reduce it on average. (If the science has been done on the differences in perception, rather than on genetic cone differences, you didn't mention it.)

I think the arguments you observe about subtle differences in color perception are more easily accounted for by aesthetic preferences. "I don't see a difference" could easily mean "I don't see an important difference."

But aside from that, I don't think anyone was actually arguing that differences in color perception don't exist. It really would be silly to deny that someone perceives what they say they perceive, without a really good reason. (Like hypochondria [edit: Munchausen syndrome would be a better example] or something.)

I did see one tongue in cheek assertion about cyan and magenta, and some discussion about the color content of grey and silver and mirrors.

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Shmuel
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quote:
Originally posted by scifibum:
You said that women might have more types of cones, but I don't see how this would necessarily change perception. If they have normal red cones and colorblind red cones, what would the colorblind cones add to the perception? It seems likely that adding less red-sensitive cones to more red-sensitive cones wouldn't improve the overall perception; in fact allowing for the same density of cones it seems like it would reduce it on average.

Oh, sure, try bringing logic into this.
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Tarrsk
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Actually, Rabbit, it's not so clear-cut as "men have one X chromosome while women have two," because of dosage compensation. Many genes have deleterious effects when expressed at higher levels than "normal." In the case of the X chromosome, "normal" (at least in humans) happens to equal 1 active copy of the chromosome. So each cell in a woman's body actually only has one actively working X chromosome, just like in males. The second X chromosome in women is silenced of gene expression via a process called X-inactivation.

I think you're actually right about there being a physiological basis for women perceiving more gradations of color than men. But it's almost certainly due to a more complex genetic program than simply the number of X chromosomes present. [Smile]

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aspectre
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"There are only three space receptors, the rest of the dimensions are mashups like magenta."

"Huh? (I didn't agree, but I understood the idea before the edit. Now I'm not really sure what you are saying.)"

Well ya got farther than I did [Big Grin] Just joking around -- kinda*sorta maybe -- with the conflation of color perception and dimensional mapping.

* However, holography is the "etching" of 3dimensional surface layer wrapped around a 3dimensional-but-otherwise-undescribed volume mapped into another 3-dimensional surface layer -- ie a 3d object mapped (with loss of information about the interior) into another 3d object -- and not a 3-dimensional object being mapped upon a 2-dimensional surface.

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Godric 2.0
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quote:
Originally posted by The Rabbit:

By definition, men have only one X chromosome and women have two.


Can I argue that definition of men and women? [Razz]
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Shmuel
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quote:
Originally posted by Godric 2.0:
quote:
Originally posted by The Rabbit:

By definition, men have only one X chromosome and women have two.


Can I argue that definition of men and women? [Razz]
I would as well, but will agree that it's less sweeping a generality than the main one at issue. [Smile]
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The Rabbit
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quote:
Originally posted by Tarrsk:
[QB] Actually, Rabbit, it's not so clear-cut as "men have one X chromosome while women have two," because of dosage compensation. Many genes have deleterious effects when expressed at higher levels than "normal." In the case of the X chromosome, "normal" (at least in humans) happens to equal 1 active copy of the chromosome. So each cell in a woman's body actually only has one actively working X chromosome, just like in males. The second X chromosome in women is silenced of gene expression via a process called X-inactivation.

Gene inactivation doesn't happen with all genes. There are a wide range of ways that the body regulated the level of gene expression and there are many gene products that get made from both gene copies in diploid organisms. For example the gene for sickle cell anemia is also found on the X chromosome. Women who are carriers for sickle cell disease have both normal hemoglobin and sickle cell hemoglobin. The sickle cell hemoglobin renders the women less susceptible to malaria but because it is only ~half the total hemoglobin the hemoglobin the "polymerization" process that happens in sickle cell crisis doesn't happen in women who carry the gene.

There is evidence that something similar happens with colorvision. Women who carry both the red/green color blind gene and the normal gene express both types of cones. That's not speculation, its been confirmed.

Anecdotally, my interaction with men who test colorblind indicates that colorblindness isn't a simple good or bad issue, there is a lot of variability in how well those who test colorblind can see color. That suggests that there aren't just two types of genes for the green cones but rather a wide spectrum of variability. If this is true, most women will carry and express two at least slightly different green cone genes where as men will carry and express only one type of green cone gene. The same arguments apply to red cone genes as well.

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The Rabbit
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quote:
Originally posted by scifibum:
You said that women might have more types of cones, but I don't see how this would necessarily change perception. If they have normal red cones and colorblind red cones, what would the colorblind cones add to the perception? It seems likely that adding less red-sensitive cones to more red-sensitive cones wouldn't improve the overall perception; in fact allowing for the same density of cones it seems like it would reduce it on average. (If the science has been done on the differences in perception, rather than on genetic cone differences, you didn't mention it.).

As I understand it, the color-blind green cones aren't "less sensitive", their response band is shifted toward the yellow. This means that for colors between red and green there is less difference between the response of the red cones and the green cones in a anomalous trichromate colorblind individual than in a normal individual. This makes it harder for the individual to discern difference in the EM spectra that range.

On the other hand, a person who has all four types of cones, has an extra spectral channel and this will allow them to detect difference in the EM spectra that can not be detected with only three channels. Since the adsorption bands for the cones are quite broad, the advantage of a forth cone in between the red and green cones is probably not large, but it would certainly be detectable mathmatically at a reasonable signal to noise ratio.

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The Rabbit
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quote:
Originally posted by Shmuel:
quote:
Originally posted by Godric 2.0:
quote:
Originally posted by The Rabbit:

By definition, men have only one X chromosome and women have two.


Can I argue that definition of men and women? [Razz]
I would as well, but will agree that it's less sweeping a generality than the main one at issue. [Smile]
How about if I say, "By the most common genetic definition"? After all I am talking genetics here.
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The Rabbit
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I just checked and I was wrong about sickle cell disease being sex linked, its autosomal recessive. I was however correct about expression of two types of hemoglobin in heterozygosis carriers of sickle cell disease. What I said about sickle does in fact hold true for other sex linked genetic disorders including anomalous trichromatic colorblindness.
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Mike
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Just curious, are there studies showing tetrachromats' enhanced spectrum-distinguishing abilities?
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King of Men
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The argument is reasonable at the level of eyes and chemical responses, but it might fall down at the level of image processing in the brain. (The famous 'qualia', as it were.) It is true that in principle four sensors will give you a better fix than three, but it is not obvious that the brain pathways develop in such a way that this is true. I would want to see some experimental data.
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The Rabbit
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Here is a scientific report on the question.
Tetrachromacy

In at least some women, tetrachromacy does in fact lead to verifiable advantages in color perception.

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Mike
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Thanks, Rabbit. The "fency" vs "grassy" section is interesting.
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King of Men
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That is interesting. I note that the what's true in physics seems true in biology as well, "the common language of science is Broken English". [Smile]
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orlox
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http://www.sciam.com/article.cfm?id=evolution-of-primate-color-vision
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