# What color is blue **URL:** \ **Category:** Factual Questions\ **Created:** [December 4, 2003, 3:04pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947 "2003-12-04T15:04:35Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![paul\_smars](https://avatars.discourse-cdn.com/v4/letter/p/3be4f8/32.png) [@paul\_smars](https://boards.straightdope.com/u/paul_smars)\ **Post date:** [December 4, 2003, 3:04pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/1 "2003-12-04T15:04:35Z")
ok. I have never gotton anyone to understand me on this. Am I just weird? We both agree that this object is blue, but how do I know that what u see as blue looks like what I see as blue. Indeed, what u see could actually be what I see when I look at something green. We just both call it by the same name, since we were tought that since birth. Understand?? ---
**Author:** ![Meeko](https://avatars.discourse-cdn.com/v4/letter/m/e495f1/32.png) [@Meeko](https://boards.straightdope.com/u/Meeko)\ **Post date:** [December 4, 2003, 3:10pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/2 "2003-12-04T15:10:15Z")
How do we know we where both tought the same name to one particular color? Well I think that people who are Color Blind could comment on this, since I am not… Out side of Colorblindness, I would think the low number (if any) of color confusion questions proves we were all taught the same way. Also, what about different languages… I don’t think the “word” matters, just as long as the end product is the same. Artits tend to be more stubborn on calling a hue or shade a more non-standard color… I have arguments with my mom (an artist) about Yellows, Mustards, Oranges etc. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [December 4, 2003, 3:11pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/3 "2003-12-04T15:11:28Z")
If I understand you correctly, you’re asking if what you call “blue” might instead be turquoise, aqaumarine, cerrulean, cobalt, robin’s egg or any of a thousand other shades that fall in roughly the same area of the color spectrum. The answer is, one person’s robin’s egg is another’s pastel. “Blue” can refer to a whole range of shades, rather than one specific point on the spectrum. If you’re color blind, then of course you don’t see blue the way I see blue. “Blue” could mean a particular shade of gray that you associate with the sky, or a sapphire, or something else that other people call blue. ---
**Author:** ![PRNYouth](https://avatars.discourse-cdn.com/v4/letter/p/9dc877/32.png) [@PRNYouth](https://boards.straightdope.com/u/PRNYouth)\ **Post date:** [December 4, 2003, 3:20pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/4 "2003-12-04T15:20:25Z")
This has nothing to do with shades and hues of the same color, I’m sure. I’m with you, **paul’smars**. There is a certain wavelength of light that my brain interprets as blue. Within my mind, that color appears blue. However the PERCEPTION of that color may be the same PERCEPTION you have of a different wavelength of light – perhaps the one that MY mind perceives as red. I don’t think the two previous posters understood what you’re saying (although kunilou got close there in that last bit about color-blindness) … but I understand, I think. Change “particular shade of gray” to “particular shade of pink” and you’re getting close to understanding what paul’smars is talking about. So if the question is, how do we know that what I see is the same as what you see? My answer is that we can’t know that. EVERYTHING in life is filtered through our own perception. Even if we were able to tap into someone else’s brain, the resulting information would STILL have to be filtered through our own perception in our own brains. No matter how hard you try, you can’t see through someone else’s eyes. That’s what this issue boils down to, I think. ---
**Author:** ![micco](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@micco](https://boards.straightdope.com/u/micco)\ **Post date:** [December 4, 2003, 3:29pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/5 "2003-12-04T15:29:51Z")
I think you’re absolutely right. There have been a number of threads on this topic, but I don’t have any links handy. I’m no expert on brain function, but let me take a crack at it, if only to stimulate the real experts into correcting me. When you see something blue, it stimulates a certain pattern of brain activity and you have been taught that that stimulation is called “blue”. My brain may fire off a completely different pattern of activity when I see blue, but I’ve been taught to label my pattern the same way you label yours. We know that this activity takes place in the same general region of the brain in everyone because different regions serve different functions, but I don’t think there’s any reason to believe that the details of the stimulus processing are the same in everyone. In fact, since brains are grown inside us rather than springing forth fully formed according to some universal pattern, it’s reasonable to expect every brain to be unique in this respect. The actual neurological activity in your brain which you label as “blue” is almost certainly completely different than mine. If we had some way to stimulate my “blue” pattern in your brain, you would have no way to interpret it, but I don’t think even the concept of that exchange of stimulation makes sense since your brain is completely different from mine (at the neurological level) and there is no neuron-to-neuron mapping between our brains that would allow a low-level duplication of brain activity. If I want to impose a blue signal on your brain, I either need to know what your brain activity looks like when it responds to blue, or I need to input the signal further upstream, maybe in the optic nerve where the signals we interpret as blue might be more universal. ---
**Author:** ![Amp](https://avatars.discourse-cdn.com/v4/letter/a/6a8cbe/32.png) [@Amp](https://boards.straightdope.com/u/Amp)\ **Post date:** [December 4, 2003, 3:31pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/6 "2003-12-04T15:31:18Z")
0000FF ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [December 4, 2003, 3:32pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/7 "2003-12-04T15:32:25Z")
**Kunilou** , it seems to me that **paul’smars’** is more complicated than that. **Paul’smars’** , I think you’re getting at something like the following: Scientist X is studying two subjects: A & B. Person A’s brain interprets the visual information yielded from a given prism in approximately the following chromatic order (as defined by X): **red, orange, yellow, green, blue, purple** Person B’s brain interprets the same visual information from the same given prism in approximately the following chromatic order (as defined by X): **green, blue, purple, red, orange, yellow** So if Person A could somehow borrow Person B’s brain, Person A would see purple bananas, green stop signs, a pale-orange-colored sky, buttery-yellow lavender flowers, etc. Yet Person B, living with a “distorted” sense of color, is none the wiser. … Now then, I must bowdlerize a bit: One simple, initial test that could be used to flesh these perceptions out would be for Scientist X to ask both A & B about the relative darkness or lightness of the colors of certain objects (probably color swatches or chips similar to those used in printing or fashion). For example, yellow objects would appear darker to B than blue objects (given equal amounts of saturation and brightness). ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [December 4, 2003, 3:34pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/8 "2003-12-04T15:34:07Z")
When asked to pick out which wavelengths were “blue”, we would presumbaly all go along with [this chart](http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html), placing “blue” at around 475_nm_. You are presumably asking whether someone else might _experience_ this wavelength differently, so that it showed up in their “vision” as what _you_ experience as “red”. Since the electromagnetic radiation of this wavelength is incident on similar receptors in the retina, there seems no reason to suppose this. However, one can never _know_ this to be the case. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [December 4, 2003, 3:37pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/9 "2003-12-04T15:37:47Z")
Sorry, what _you_ experience as " **green"**. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 4, 2003, 3:41pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/10 "2003-12-04T15:41:42Z")
If I understand the question correctly, it’s the same as asking: “When I poke people in their right arms, do they all feel the same sensation? What you feel as pain in the right arm may be what I call a pain in the right thigh.” In that case, I think the answer is that the exact electro-chemical response to the same stimulus is slightly different for everyone, but their brains interpret them appropriately. So if I transplant my brain onto your body, it may take some time for the brain to learn what signal corresponds to “pain in right arm”. There is a famous experiment where test subjects wear eyeglasses with prisms that invert the image. They are of course terribly disoriented at first, but after some time (few days?) they get used to it. When they finally remove the glasses, they become disoriented again for a while. This seems to indicate that the brain needs to - and can - learn and re-learn which signal means “light in the upward direction.” I don’t know if anyone has done an experiment which replaces green light with red (for example), but that might be interesting… ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [December 4, 2003, 3:50pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/11 "2003-12-04T15:50:48Z")
> [@](#): > > \*Originally posted by SentientMeat \* > \*\*Since the electromagnetic radiation of this wavelength is incident on similar receptors in the retina, there seems no reason to suppose this. However, one can never _know_ this to be the case. \*\* It seems to be that comparing preceptions of the relative lightness and darkness of colors might be a first step in determining that people pretty much perceive the chromatic spectrum the same way. For instance, if Persons A & B from my first post were each asked to draw a grayscale representation of the prism’s refraction, Person A would draw something like: 50% gray | 20% gray | 5% gray | 20% gray | 50% gray | 70% gray Person B would draw it like so: 20% gray | 50% gray | 70% gray | 50% gray | 20% gray | 5% gray So the difference in color preception would make itself self-evident. ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [December 4, 2003, 4:01pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/12 "2003-12-04T16:01:34Z")
> [@](#): > > \*Originally posted by paul’smars \* > \*\* > > We both agree that this object is blue, but how do I know that what u see as blue looks like what I see as blue. Indeed, what u see could actually be what I see when I look at something green. We just both call it by the same name, since we were tought that since birth. Understand?? \*\* If you mean that, given a particular color sample, your visual experience may be different than my visual experience, but somehow we have a matching descriptive name for two different wavelengths… How about this test: Prepare two sets of color samples… say about a dozen different hues in the “blue” range. The color samples are numbered on the back. You and I then see if we can agree enough to match-up our samples (under the same light source) based on what we _see_, rather than by naming the colors. If our numbers match, then we know our perceptions of the colors match, and we can procede to agree on names. Howzat? Meanwhile… Sky Blue Royal Blue Blue Dark Blue Green Indigo 😉 ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [December 4, 2003, 4:05pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/13 "2003-12-04T16:05:02Z")
Philosophically, the question is unanswerable as it deals with the qualia of colour. However, and I don’t have a cite right now, some study showed that humans differ by most 2 parts in 255 in perceiving a color on a computer selected using a standard true colour palette. ---
**Author:** ![randwill](https://avatars.discourse-cdn.com/v4/letter/r/a3d4f5/32.png) [@randwill](https://boards.straightdope.com/u/randwill)\ **Post date:** [December 4, 2003, 4:25pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/14 "2003-12-04T16:25:42Z")
I think we all percieve colors pretty much the same. It’s why, most of the time, if you ask a kid his favorite color, he/she will say Red. ---
**Author:** ![Intaglio](https://avatars.discourse-cdn.com/v4/letter/i/71e660/32.png) [@Intaglio](https://boards.straightdope.com/u/Intaglio)\ **Post date:** [December 4, 2003, 5:32pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/15 "2003-12-04T17:32:17Z")
Cyan is Blue in Printing. ---
**Author:** ![CheekyMonkey613](https://avatars.discourse-cdn.com/v4/letter/c/e480ec/32.png) [@CheekyMonkey613](https://boards.straightdope.com/u/CheekyMonkey613)\ **Post date:** [December 4, 2003, 5:50pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/16 "2003-12-04T17:50:06Z")
Paul … I’ve thought the EXACT same thing myself Furthermore, if we DO all see different colours as the same colour, then maybe our FAVOURITE colour is always the same colour! LOL … also thinking … this could explain why people have such BAD taste sometimes in colour combos. 😉 ---
**Author:** ![SubliminaLiar](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@SubliminaLiar](https://boards.straightdope.com/u/SubliminaLiar)\ **Post date:** [December 4, 2003, 6:13pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/17 "2003-12-04T18:13:51Z")
I’m with you on this, paul’smars… I used to ponder the very same question as a child in school, looking at crayons. **’Would a rose, by any other name’…** well, ya know the rest. Yellow Green Blue Orange Black Oh well; as long as we all agree to STOP for red lights\* (or whatever color we associate with ‘red’) \* then we’re all on the same… wavelength, so to speak. 😛 ---
**Author:** ![paul\_smars](https://avatars.discourse-cdn.com/v4/letter/p/3be4f8/32.png) [@paul\_smars](https://boards.straightdope.com/u/paul_smars)\ **Post date:** [December 4, 2003, 8:18pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/18 "2003-12-04T20:18:05Z")
PRNYouth Exactly ! micco Your last sentence lost me. Amp huh ?? It that hexi-decimal? bordelond Yea, except that I am not sure about your last paragraph. gluteus maximus Would your test prove anything?? CheekyMonkey613 hmmmm, that’s why I can never match my clothes(not joking) SubliminaLiar Thanks, its nice to know that I am not the only one. ---
**Author:** ![micco](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@micco](https://boards.straightdope.com/u/micco)\ **Post date:** [December 4, 2003, 8:28pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/19 "2003-12-04T20:28:22Z")
> [@](#): > > \*Originally posted by paul’smars \* > **micco > Your last sentence lost me.** Maybe I was getting too far afield. The point was that if you wanted some sci-fi helmet that inserted sensations directly in your brain, it would have to be customized to the individual so it would know what specific brain activity to stimulate for any given simulated perception. AFAIK, there is no universal “blue” brain activity pattern you could insert. On the other hand, if you’re inserting data farther out in the neurological chain, say in the optic nerve instead of the brain, it might be possible to define stimulation patterns that were the same for all individuals. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [December 4, 2003, 10:51pm UTC](https://boards.straightdope.com/t/what-color-is-blue/216947/20 "2003-12-04T22:51:48Z")
> [@](#): > > \*Originally posted by paul’smars \* > \*\*ok. I have never gotton anyone to understand me on this. Am I just weird? > > We both agree that this object is blue, but how do I know that what u see as blue looks like what I see as blue. Indeed, what u see could actually be what I see when I look at something green. We just both call it by the same name, since we were tought that since birth. Understand?? \*\* We don’t know and we don’t have to either. As long as we both call it blue it doesn’t matter what we individually and privately see inside our heads. Consider the rainbow. If an artist and I are standing side by side looking at one and he or she paints a picture, if we both have normal color vision, I will say that what I see in his painting has the same colors as the thing I see in the sky. [Next page](https://boards.straightdope.com/t/what-color-is-blue/216947.md?page=2)