Is she just talking crazy, or is that true? I don't see how it can be, but it seems like a strange thing to invent.
Posted by mr_porteiro_head (Member # 4644) on :
Megenta totally exists as an artifact of our trichromate eyes.
Posted by scifibum (Member # 7625) on :
Wikipedia agrees, though putting it in slightly more comprehensible terms:
quote:It is an extra-spectral color, meaning it cannot be generated by a single wavelength of light, being a mixture of red and blue wavelengths.
"Magenta does not exist" is nonsensical, but "Magenta is not on the color spectrum" seems to be accurate.
Edit: White would seem to be in the same category.
Posted by ricree101 (Member # 7749) on :
As far as I know, it is true that Magenta isn't a color in the sense that it doesn't correspond to any one frequency of light.
It makes sense, I suppose. If you look at the eye's response to different frequencies, there really isn't anywhere that would give a strong response on red and blue, but not green. Yet that can clearly happen if there are multiple frequencies hitting the eye, so there needs to be some way for the brain to interpret it.
It also makes sense if you look at it on the color wheel. On it, magenta ends up between red and blue, but on the real em spectrum, there is no wraparound since IR, radio, etc are past red and UV, xray, gamma, etc are past blue.
Posted by Achilles (Member # 7741) on :
This is one of the many artifact of our trichromate eyes. For example, our eyes respond exactly the same to a single monchromatic light source at 510 nm (green) and two monochromatic light sources on at 570 nm (yellow) and one at 450 nm (indigo). Spectroscopically, these are very different phenomena but we can't distinguish between the two with our eyes. The difference is particularly obvious when you mix red (600 nm) and blue (475 nm) light and the eye interprets it exactly the same as 400 nm (purple) light.
I don't think its fair to say magenta doesn't exist or is something made up by our brain, it is a distinct spectroscopic phenomenon it just isn't a monochromatic spectroscopic phenomenon. It is interesting that for most of the color spectrum, we can experience the same color in more than one way -- either monochromatically or polychromatically. However, we only experience the colors that are mixtures of red and violet as a result of polychromatic stimuli. Maybe we should consider these the only "true" colors.
Posted by The Rabbit (Member # 671) on :
As a scientist, I find the fact that our eyes our trichromatic sensors to be highly disappointing. If we had 4 or 5 or more different color sensors instead of only three, we could use color as a means to represent 4 or 5 or higher dimensional data.
It seems nature has conspired against us. We a beings living in a 7 dimensional universe who are limited to visualizing that universe in only 3 dimensions.
Posted by King of Men (Member # 6684) on :
quote:For example, our eyes respond exactly the same to a single monochromatic light source at 510 nm (green) and two monochromatic light sources on at 570 nm (yellow) and one at 450 nm (indigo).
This seems odd to me. Are you sure it's not our brains that are responding the same? I would have thought that the light-sensitive chemicals in the cells would react a little differently to these two stimuli; if R is a resonance frequency, then the response to R and to 0.5(R+x, R-x) is generally not the same.
Posted by Shigosei (Member # 3831) on :
I've been fascinated for awhile by colors and our perception of them. It turns out that purple -- a mix of blue and red -- is different from violet, which is the end of the visible spectrum. Purple and violet very similar to us because they trigger our retinal cells in a similar way, but the actual wavelengths of light reaching our eyes are not the same. This is more or less how color mixing works. Blue and yellow trigger the same reaction that a pure green light would.
Fascinating, isn't it? Brown, white, and purple are to some degree just in your head.
Posted by King of Men (Member # 6684) on :
quote:t seems nature has conspired against us. We a beings living in a 7 dimensional universe who are limited to visualizing that universe in only 3 dimensions.
Where do you get the 7? The actual information consists of a Fourier analysis, which in some sense is infinite-dimensional: Intensity A1 at frequency B1, A2 at B2, and so on. In practice there are limits to how finely you can subdivide your sensor max-response ranges. But while there's nothing special about 3, what's special about 7?
Posted by Noemon (Member # 1115) on :
quote:Originally posted by Shigosei:
Fascinating, isn't it?
It really is. This whole thread makes me happy.
Posted by The Rabbit (Member # 671) on :
KoM, I'm fairly confident that the nerve signals going to the brain are identical. I'm less certain about the actual photo responce of the light sensitive chemicals but it is my understanding that they are excited over a relatively broad spectral band.
Since I have worked designing sensors, it is not that difficult to see how this would work. You have three optically active chemicals each of which is excitied by a different range of the EM spectrum but there is some over lap in the range. Chemical A might absorb in the blue and chemical B might absorb in the yellow but both chemicals have a broad enough absorption band that they are excited in the green. So green light will excited both A and B, but you can get exactly the same response using the appropriate intensities of blue light that excites only A and yellow light that excites only B.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by King of Men:
quote:t seems nature has conspired against us. We a beings living in a 7 dimensional universe who are limited to visualizing that universe in only 3 dimensions.
Where do you get the 7? The actual information consists of a Fourier analysis, which in some sense is infinite-dimensional: Intensity A1 at frequency B1, A2 at B2, and so on. In practice there are limits to how finely you can subdivide your sensor max-response ranges. But while there's nothing special about 3, what's special about 7?
I was referring to the 7 spatial dimensions of the universe postulated by certain physicists.
I suppose I should explain. I've been working developing methods for visualizing high dimension data sets. When visualizing data, color can be used to represent variables that have no relationship to the EM spectra just like distance on a graph can be used to represent variables that have no relationship to physical distance. Unfortunately, because our eyes are only trichromatic, you cannot represent more than three dimensions uniquely using color. Its very disappointing.
Posted by King of Men (Member # 6684) on :
quote:KoM, I'm fairly confident that the nerve signals going to the brain are identical. I'm less certain about the actual photo responce of the light sensitive chemicals but it is my understanding that they are excited over a relatively broad spectral band.
Since I have worked designing sensors, it is not that difficult to see how this would work. You have three optically active chemicals each of which is excitied by a different range of the EM spectrum but there is some over lap in the range. Chemical A might absorb in the blue and chemical B might absorb in the yellow but both chemicals have a broad enough absorption band that they are excited in the green.
Yes, but to fine-tune the response so that you get exactly the same net intensity seems unlikely. Although, on second thought, perhaps it was for just that reason that you quoted those precise numbers?
quote:I was referring to the 7 spatial dimensions of the universe postulated by certain physicists.
Oh, ok, but why stop at seven? With properly designed eyes you could have twenty dimensions, and you've got a lot more electromagnetic spectrum to play with than the boring visible-light stuff as well. I'm sure there are any number of applications where 20 dimensions would be useful.
Posted by orlox (Member # 2392) on :
You sure you are not thinking of the cross product [of Euclidean space] or perhaps M theory's 11 dimensions?
[ February 17, 2009, 10:12 PM: Message edited by: orlox ]
Posted by Jon Boy (Member # 4284) on :
quote:Originally posted by King of Men:
quote:For example, our eyes respond exactly the same to a single monochromatic light source at 510 nm (green) and two monochromatic light sources on at 570 nm (yellow) and one at 450 nm (indigo).
This seems odd to me. Are you sure it's not our brains that are responding the same? I would have thought that the light-sensitive chemicals in the cells would react a little differently to these two stimuli; if R is a resonance frequency, then the response to R and to 0.5(R+x, R-x) is generally not the same.
I believe Rabbit is correct, though I'm not sure about the exact colors she chose; if I understand correctly, yellow and blue light should make white. But, for instance, a yellow light of the right frequency will stimulate the green and red receptors in the eyes just as a mix of green and red lights of the right frequency will.
Posted by The Genuine (Member # 11446) on :
I'm pretty sure Chuck Norris can make or destroy magenta at will.
Posted by Wonder Dog (Member # 5691) on :
Why can't you combine the 3 color dimensions (RGB) to get more than 3 dimensions of information? Eg: "Redness", "greenness" and "blueness" each correspond to a dimension, but "yellowness" and "tealness" do too... or would "yellowness" signify high values in both the red and green dimensions?
Rabbit, would you consider yourself a "visual analytics" researcher? There are folks at my school who specialize in visual analytics, but I was under the impression that it was a relatively new field...
Posted by mr_porteiro_head (Member # 4644) on :
quote:Why can't you combine the 3 color dimensions (RGB) to get more than 3 dimensions of information? Eg: "Redness", "greenness" and "blueness" each correspond to a dimension, but "yellowness" and "tealness" do too... or would "yellowness" signify high values in both the red and green dimensions?
To your brain, yellowness is nothing other than redness + greeness, which would mean it's not independent of those two dimensions, which means it can't be used as a separate dimension.
Posted by Jon Boy (Member # 4284) on :
Yup. The color space as we perceive it is [±red], [±green], and [±blue]. This is all that is needed to describe all the colors visible to the human eye. If you throw in features like [±teal], then things stop making sense, because then you could define a color as [–red, –green, –blue, +teal], and that doesn't exist.
Posted by kmbboots (Member # 8576) on :
quote:Originally posted by Noemon:
quote:Originally posted by Shigosei:
Fascinating, isn't it?
It really is. This whole thread makes me happy.
Indeed. And this has, for some time*, been one of the reasons that the colours in the red-to-violet range are my favourites.
*Okay, since TMG pointed it out to me.
Posted by Starsnuffer (Member # 8116) on :
I feel like I've heard in an intro psych class speaks of a range of up to 5 different photochromic pigments. So having none of those would render you black and white movie colorblind, having three of them would be "normal" vision, and having further just makes your perception of normal color more subtly varied.
Not that it would allow magenta or the like to be a single EM wavelength.
Also, I would really like goggles that could be tuned to show me various ranges of the EM spectrum (so if I wanted to see IR through UV it would show me the lowest energy IR as visible red and the highest energy UV as visible violet (so I could see it). Or just IR goggles... because seriously, so cool.
(Hrm. I keep thinking of problems with my dream goggles)
Posted by aspectre (Member # 2222) on :
There are only three space receptors, the rest of the dimensions are mashups like magenta.
[ February 18, 2009, 12:24 AM: Message edited by: aspectre ]
Posted by orlox (Member # 2392) on :
Huh?
(I didn't agree, but I understood the idea before the edit. Now I'm not really sure what you are saying.)
Posted by mr_porteiro_head (Member # 4644) on :
So, why does indigo look purplish to our eyes?
Also, my artist wife informs me that if you combine red and blue paint, you'll get really ugly purples. To get good looking purple, you have to combine magenta and cyan. Anybody know why that might be?
--
So, white light is nothing more than the R, G, and B receptors being stimulated approximately equally. Our computer monitors do this with three colors -- one R, one G, and one B. But it would be possible to create white light (to our brains) using only two colors -- one between R and G, and the other between G and B. I wonder what the color space using those two colors would look like.
Also, the talk of the 3D color space that we perceive made me realize that there are a finite number of colors we can perceive. In each of the 3 dimensions there are only so many gradients that we can perceive as separate from each other. Combine those all together, and you've got a finite number of colors. This means that a sufficiently good computer monitor could perfectly display any image our eyes can perceive. Ignoring bifocal effects, of course.
Posted by twinky (Member # 693) on :
I just can't take you seriously when you use the word "colour". Posted by scifibum (Member # 7625) on :
"This means that a sufficiently good computer monitor could perfectly display any image our eyes can perceive. Ignoring bifocal effects, of course."
If it's sufficiently good we don't have to ignore bifocal effects. Posted by mr_porteiro_head (Member # 4644) on :
Fine.
This means that a sufficiently good computer monitor of the same basic type that we use today could perfectly display any image that our eyes can perceive. Ignoring bifocal effects, of course.
Posted by fugu13 (Member # 2859) on :
Porter: while we're getting pretty close to showing the full spectrum of colors on a monitor (provided you're willing to spend a few thousand dollars), but what we're really lacking is resolution. The eyes are far, far higher (effective) resolution than we can easily reproduce on a monitor.
At the distances people commonly work on monitors, many humans can distinguish up to somewhere around 600 dpi (possibly a lot more in certain circumstances, but 600 is a good place to get an idea of how far off we are). Right now monitors are typically around 100 dpi equivalent (they tend to say something like 300 dpi, but they include dots that are really right on top of each other -- the three color dots. To compare with print dpi, use ppi for monitors). Some get up to around 150 (some of the handhelds get more, but their screens are held closer to the face, meaning the eye can see even more dpi), but that's relatively rare.
1080p (on a 42 inch screen) is only 52 ppi. Of course, you don't usually sit as close to a TV as you do a monitor, so the eye's effective resolution is less at that range. Not that low, though.
edit: also worth noting, the eyes aren't purely additive. No monitor that only mixes RGB can show everything the eyes can see, because we can see some things that can only be expressed by subtracting some of the factors.
Posted by Starsnuffer (Member # 8116) on :
quote:Also, the talk of the 3D color space that we perceive made me realize that there are a finite number of colors we can perceive.
Well... there's a finite number of colors in the same way there's a finite number of fractions, or a finite number of distances you can be away from a wall. To say the number is finite seems... not true. You could have wavelengths of light that are 500nm combined with 400nm light but then you can have 500.000001nm 500.000002nm etc. And every combination of those continuously variable values, so it seems like the number of possible perceived colors should be infinite.
Posted by mr_porteiro_head (Member # 4644) on :
Yes, there are an infinite number of wavelengths in the visible spectrum, but that's not what I'm talking about.
The human eye/brain cannot distinguish between 500nm and 500.000000000001nm. To our eye/brain, those two wavelengths are exactly the same color.
Our red, green, and blue receptors cannot pick up infinite gradients -- there is a finite number of colors that we can distinguish as separate. Multiply the number of gradients we can perceive for R, G, and B, and you've got the finite number of colors it is possible for us to distinguish.
Posted by scifibum (Member # 7625) on :
"Yes, there are an infinite number of wavelengths in the visible spectrum..."
Is this true? I don't mean can we come up with an infinite number of fractions between 500 and 501. What I mean to ask is whether light can actually be produced on any such wavelength. Or is light energy only possible in certain discrete quanta?
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by scifibum: "Yes, there are an infinite number of wavelengths in the visible spectrum..."
Is this true? I don't mean can we come up with an infinite number of fractions between 500 and 501. What I mean to ask is whether light can actually be produced on any such wavelength. Or is light energy only possible in certain discrete quanta?
To the best of my knowledge, the light spectrum is continuous so it is possible to produce light with any real number wave length. You may be confusing wavelength with intensity and the intensity of light at a given wavelength exist only as discrete quanta.
Posted by mr_porteiro_head (Member # 4644) on :
That's my understanding as well.
Posted by Tresopax (Member # 1063) on :
The confusion here stems from a misunderstanding of the concept of color that stems from the way we casually mix up talk of colors and the wavelengths that cause them. A color is not a wavelength. A color is an experience.
Or, as the Ars Technica article puts it: "The truth is, no color actually exists outside of our brain's perception of it. Everything we call a color—and there are a lot more than what comes in your box of Crayolas—only exists in our heads."
Posted by mr_porteiro_head (Member # 4644) on :
quote:The confusion here stems from a misunderstanding of the concept of color that stems from the way we casually mix up talk of colors and the wavelengths that cause them. A color is not a wavelength. A color is an experience.
Or rather, the confusion stems from the fact that the word "color" means more than one thing.
[ February 18, 2009, 01:36 PM: Message edited by: mr_porteiro_head ]
Posted by scifibum (Member # 7625) on :
quote:Originally posted by The Rabbit:
quote:Originally posted by scifibum: "Yes, there are an infinite number of wavelengths in the visible spectrum..."
Is this true? I don't mean can we come up with an infinite number of fractions between 500 and 501. What I mean to ask is whether light can actually be produced on any such wavelength. Or is light energy only possible in certain discrete quanta?
To the best of my knowledge, the light spectrum is continuous so it is possible to produce light with any real number wave length. You may be confusing wavelength with intensity and the intensity of light at a given wavelength exist only as discrete quanta.
Thanks for the answer. I was not confusing intensity with wavelength. I understood that at a given wavelength the energy of light is quantized (the factors being Planck's constant and the number of photons).
You did answer my real question, which was whether wavelength is continuously variable. I think my doubt about this stemmed from the simplistic explanation I received when I was in physics classes that light is generated from electrons falling into lower energy states around atomic nuclei. Since those energy levels and the number of electrons are discrete, I figured light from those events would have a discrete set of wavelengths.
But (I've learned in the last few minutes) the other ways in which photons can be generated aren't necessarily limited to discrete energy levels.
Also the wavelength of a photon depends on reference frame which itself is variable.
So I think I get it now.
Posted by Mike (Member # 55) on :
I can feel another qualia debate coming on...
Posted by BandoCommando (Member # 7746) on :
KoM's and The Rabbit's discussion makes it almost inevitable for a Star Trek geek like me to be reminded of Geordi's visor. Wouldn't that be a multi-dimensional sensor device?
Posted by rivka (Member # 4859) on :
quote:Originally posted by mr_porteiro_head: So, white light is nothing more than the R, G, and B receptors being stimulated approximately equally.
Not equally. We have a yellow sun, which produces light with a peak skewed in the blue-green direction.
Look, purty! Posted by The Rabbit (Member # 671) on :
quote:Also, my artist wife informs me that if you combine red and blue paint, you'll get really ugly purples. To get good looking purple, you have to combine magenta and cyan. Anybody know why that light be?
Mixing dyes and pigments is fundamentally different from mixing light. Dyes and pigments work by absorbing a large portion of the EM spectrum present in white light and reflecting back only a narrow spectral band. So for example, leaves are green because they absorb strongly in the red which leaves the reflected light depleted of red. Because of this Dyes and pigments are subtractive, or rather it is the amount absorbed that is added rather than the amount that is reflected. So if you mix together green paint and red paint, the green paint will absorb all the red light and the red paint will absorb the green light and what's left will be the original white light minus red and green (kind of an ugly brown). If you mix together dyes of every color in the spectrum, you get black because it absorbs everything.
Exactly the opposite happens when you mix light sources. If you take a green light and red light and focus them both on the same spot, you will get green wavelength light and red wavelength light hitting the spot which your brain will interpret as yellow. If you focus all wavelengths in the visible spectrum on the same spot, you get white.
Because our eyes are trichromatic, you don't have to have all wavelengths to perceive "white" and you don't have to mix all colored dyes to perceive "black". You only need three primary colors but because the mixing rules are different the three primary colors for mixing light are red, green and blue. The three primary colors for mixing dyes are cyan, yellow and magenta.
Posted by mr_porteiro_head (Member # 4644) on :
quote:Originally posted by rivka:
quote:Originally posted by mr_porteiro_head: So, white light is nothing more than the R, G, and B receptors being stimulated approximately equally.
Not equally. We have a yellow sun, which produces light with a peak skewed in the blue-green direction.
So doesn't it produce yellowish, instead of white light?
Posted by rivka (Member # 4859) on :
quote:Originally posted by The Rabbit: The three primary colors for mixing dyes are cyan, yellow and magenta.
And you should have heard the senior physics students I used to teach when they learned that! After all, from preschool on, everyone teaches you RBY.
[Edit: oops!]
[ February 18, 2009, 05:16 PM: Message edited by: rivka ]
Posted by The Rabbit (Member # 671) on :
quote:Rabbit, would you consider yourself a "visual analytics" researcher? There are folks at my school who specialize in visual analytics, but I was under the impression that it was a relatively new field...
No I'm not really a visual analytics researcher. In my researcher, I do a great deal of processing of hyperspectral images and that has lead me to investigate a bit about visual analytics. I'm by know means an expert in that field, I know just enough to get myself in trouble.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by rivka:
quote:Originally posted by The Rabbit: The three primary colors for mixing dyes are cyan, yellow and magenta.
And you should have heard the senior physics students I used to teach when they learned that! After all, from preschool on, everyone teaches you RBG.
When I was in school, it was red, yellow and blue.
Posted by rivka (Member # 4859) on :
quote:Originally posted by mr_porteiro_head:
quote:Originally posted by rivka:
quote:Originally posted by mr_porteiro_head: So, white light is nothing more than the R, G, and B receptors being stimulated approximately equally.
Not equally. We have a yellow sun, which produces light with a peak skewed in the blue-green direction.
So doesn't it produce yellowish, instead of white light?
Yup. But that's not what we call it.
quote:Originally posted by The Rabbit: When I was in school, it was red, yellow and blue.
Oops!
Posted by fugu13 (Member # 2859) on :
Unless there's an even more minor field by the same name, visual analytics has nothing to do with analyzing images (well, you could apply it to analyzing images, but no more than anything else).
Visual analytics is about making (usually) interactive visualizations to help people understand large amounts of data.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by fugu13: Unless there's an even more minor field by the same name, visual analytics has nothing to do with analyzing images (well, you could apply it to analyzing images, but no more than anything else).
Visual analytics is about making (usually) interactive visualizations to help people understand large amounts of data.
You are correct. My interest in visual analytics has been because ultimately analysis of hyperspectral images leads you to seek for ways to effectively present those complex data sets to people, and so my research requires some understanding of visual analytics, though as I said I am not a visual analytics researcher.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by rivka:
quote:Originally posted by The Rabbit: When I was in school, it was red, yellow and blue.
Oops! [/QB]
Yup, Here is a link to the wiki article on the RYB (Red, Yellow, and Blue) color system. It appears my primary education predates modern color theory.
Posted by rivka (Member # 4859) on :
Perhaps so. But guess what they're teaching in kindergartens across the nation, right at this very moment?
Posted by The Rabbit (Member # 671) on :
On a related note, over the years I have been in and observed enough arguments between men and women about subtle color differences that I had concluded that all men were color blind.
I even had a theory to explain it. Here it is. The genes for red and green cones are on the X chromosome which is why red green color blindness is dominant in men but not in women. There are two basic types of read green color blindness. In the first type, the person is completely missing either the gene for either red or green cones so they can not see any difference between red and green. (This is called dichromatism) In the more common type of red green color blindness, the person has a defect in either the red or green cone which makes the two cones more similar hence the person is still able to see differences between red and green but those differences are more subtle. (Anomalous Trichromacy) These people often have no idea they are color blind until they take a test specifically designed to detect this problem. (This much is fact, not my theory.)
I'm speculating that this color blindness defect isn't as simple binary good cone/bad cone issue but that there is actually a range of variability in the response curves for red and green cones. Since women have two X chromosomes, they will have two genes for red cones and two genes for greens cones and its unlikely that both genes will be identical so most women will have two different red cones with slightly different response curves and two different green cones with slightly different response curves where as men will have only one type of red cone and one type of green cone. Most men and women will also have two different genes for blue cones since those genes aren't on the X chromosome.
So anyway, I've speculated for years that this is why women were more sensitive to subtle differences in color than men.
Well this thread just inspired me to do a search and see if any one had researched the question and it turns out my speculations were correct. Or at least most of it has been confirmed. Some women at least have 4 or 5 distinctly different cones blue, normal red and colorblind red, normal green and colorblind green where as men have at most three different types of cones. (There is still potential that both men and women have two measurably different types of blue cones which would make up to 4 cones for men and up to 6 for women but I haven't been able to confirm that).
So there you have it: All men are colorblind.
As a side note, this implies that women (like me) who have a Father with anomalous trichromacy, who are not colorblind but carry the gene for colorblindness have enhanced colorvision. Thanks Dad!
[ February 18, 2009, 06:09 PM: Message edited by: The Rabbit ]
Posted by Lisa (Member # 8384) on :
quote:Originally posted by The Rabbit:
quote:Originally posted by rivka:
quote:Originally posted by The Rabbit: When I was in school, it was red, yellow and blue.
Oops!
Yup, Here is a link to the wiki article on the RYB (Red, Yellow, and Blue) color system. It appears my primary education predates modern color theory. [/QB]
Me, too. I read through that article, and I still don't get what's wrong with RYB.
Posted by mr_porteiro_head (Member # 4644) on :
quote:n the RGB color model the colors are added, so that one starts with levels of dark colors, which are added together to produce lighter colors. RYB uses pigments which are not added, so that combining colors using the RYB color system will result in a darker color. Because of this, it is impossible to create magenta, since its value would normally be the combined value of red and blue, but combining them using pigments creates a darker color (namely purple or violet). Similarly, it is impossible to create a true cyan. Therefore, any color between red and blue must be darker than red and blue, and any color between yellow and red or yellow and blue must be darker than yellow.
Ah! That explains my question about purple. Thank you!
(Well, Rabbit explained it earlier. But because of this wikipedia quote, I understand it better.)
Posted by The Rabbit (Member # 671) on :
Well not all women, but at least some. And no men are tetrachromates.
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.
Posted by The Rabbit (Member # 671) on :
MPH edited his post to make my response look weird. I should have suspected something was up when the I tried to quote him using the " " link and it wouldn't work.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by mr_porteiro_head: [QUOTE](Well, Rabbit explained it earlier. But because of this wikipedia quote, I understand it better.)
The wikipedia explanation is much clearer than mine, even to me.
Posted by mr_porteiro_head (Member # 4644) on :
quote:MPH edited his post to make my response look weird. I should have suspected something was up when the I tried to quote him using the " " link and it wouldn't work.
Sorry about that. I made that post without reading all of your post. Namely, the part where you said exactly what I was saying.
Posted by Shmuel (Member # 7586) on :
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. Posted by The Pixiest (Member # 1863) on :
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.
Posted by advice for robots (Member # 2544) on :
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.
Posted by mr_porteiro_head (Member # 4644) on :
Grey and silver are the exact same color, but with different reflective properties.
Posted by rivka (Member # 4859) on :
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.
Pfft. Who combines construction paper colors?
FINGER PAINTS! Posted by Mike (Member # 55) on :
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. Posted by Jon Boy (Member # 4284) on :
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?
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.
Posted by Shmuel (Member # 7586) on :
quote:Originally posted by rivka: Pfft. Who combines construction paper colors?
FINGER PAINTS!
A good point.
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. Posted by Pegasus (Member # 10464) on :
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.... Posted by rivka (Member # 4859) on :
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! ) Magenta is a red/blue, not a red; cyan is a blue/green, not a blue.
Posted by Jon Boy (Member # 4284) on :
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. Posted by rivka (Member # 4859) on :
We have an outside person create our color ads. But how would I know which colorspace I was using, in, say, Publisher?
Posted by scifibum (Member # 7625) on :
Grey IS colorless.
Posted by rivka (Member # 4859) on :
No. Grey is not white.
Posted by lobo (Member # 1761) on :
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...
Posted by mr_porteiro_head (Member # 4644) on :
quote:Originally posted by Mike: So a mirror is grey?
I'd say no, and it's not silver-colored either.
Posted by rivka (Member # 4859) on :
Huh. What color is it?
Posted by mr_porteiro_head (Member # 4644) on :
It's not. It's a mirror. Posted by rivka (Member # 4859) on :
. . . um. And mirrors are outside the definitions of color?
Posted by Jon Boy (Member # 4284) on :
What color is it when it's not reflecting anything? 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.
Posted by scifibum (Member # 7625) on :
quote:Originally posted by rivka: No. Grey is not white.
Grey is white. Just less of it.
Posted by scifibum (Member # 7625) on :
quote:Originally posted by Jon Boy: What color is it when it's not reflecting anything? 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).
Posted by Jon Boy (Member # 4284) on :
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. Posted by rivka (Member # 4859) on :
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.
Posted by mr_porteiro_head (Member # 4644) on :
quote:What color is it when it's not reflecting anything? [Razz]
*tuns mirror around and looks at the back side*
Grey.
Posted by scifibum (Member # 7625) on :
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 Posted by The Rabbit (Member # 671) on :
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.
Posted by kmbboots (Member # 8576) on :
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.
Posted by Jon Boy (Member # 4284) on :
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.
Posted by Noemon (Member # 1115) on :
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).
Posted by Jon Boy (Member # 4284) on :
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.
Posted by scifibum (Member # 7625) on :
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.
Posted by Mike (Member # 55) on :
"Cute".
Posted by The Rabbit (Member # 671) on :
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.
Posted by scifibum (Member # 7625) on :
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.
Posted by Shmuel (Member # 7586) on :
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.
Posted by Tarrsk (Member # 332) on :
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. Posted by aspectre (Member # 2222) on :
"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 Just joking around -- kinda*sortamaybe -- 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.
Posted by Godric 2.0 (Member # 11443) on :
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? Posted by Shmuel (Member # 7586) on :
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?
I would as well, but will agree that it's less sweeping a generality than the main one at issue. Posted by The Rabbit (Member # 671) on :
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.
Posted by The Rabbit (Member # 671) on :
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.
Posted by The Rabbit (Member # 671) on :
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?
I would as well, but will agree that it's less sweeping a generality than the main one at issue.
How about if I say, "By the most common genetic definition"? After all I am talking genetics here.
Posted by The Rabbit (Member # 671) on :
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.
Posted by Mike (Member # 55) on :
Just curious, are there studies showing tetrachromats' enhanced spectrum-distinguishing abilities?
Posted by King of Men (Member # 6684) on :
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.
Posted by The Rabbit (Member # 671) on :
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.
Posted by Mike (Member # 55) on :
Thanks, Rabbit. The "fency" vs "grassy" section is interesting.
Posted by King of Men (Member # 6684) on :
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". Posted by orlox (Member # 2392) on :
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