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Here is a picture of the visible spectrum. Can you find the color magenta?

Visible Spectrum (Gringer)

Why can't you find magenta in the visible spectrum? This is because magenta cannot be emitted as a wavelength of light. Yet magenta exists; you can see it on this color wheel.

Color Wheel (Gringer)

Magenta is the complementary color to green, or the color of the afterimage you would see after you stare at a green light. All of the colors of light have complementary colors that exist in the visible spectrum, except for green's complement, magenta. Most of the time your brain averages the wavelengths of light you see in order to come up with a color. For example, if you mix red light and green light, you'll see yellow light. However, if you mix violet light and red light, you see magenta rather than the average wavelength, which would be green. Your brain has come up with a way to bring the ends of the visible spectrum together in a way that makes sense. Pretty cool, don't you think?

Comments

February 22, 2010 at 4:08 am
(1) Normajean says:

This blows my mind. I am going to read this again to see if my brain can get this. Magenta ? Who wooda thunk it ? Science has always been my favorite subject. Thank you for this most incredible blog.

February 22, 2010 at 4:48 am
(2) Art says:

Interesting, but I still don’t get it.

November 18, 2011 at 10:36 am
(3) Fievel says:

@Art

The article is showing how no single-wavelength source of light (ROYGBIV) can create the Magenta color.

Magenta is a product of how your brain attempts to reconcile a mix between purple and red.

February 22, 2010 at 8:23 am
(4) TeeK says:

If you mix violet and red light, you get a violet shifted towards the red end of the spectrum. Violet itself is a mixture of red and blue.

The colors of the spectrum do not include magenta, as it is simply a minor spectrum of violet. “Magenta” is only a name. By the same reasoning that we can “see” many colors not in the visable spectrum, like cream, black, gold, silver, bronze, etc.

I cannot see quite what you mean by our brains magically bringing both ends of the spectrum together? – Whatever color we see, is simply a mixture of two or three of the main colors – See additive colors for a better explanation:

http://en.wikipedia.org/wiki/Additive_color

So magenta is simply a particular minor range of the intensities of blue and red light mixed together, along with the more traditionally named Indigo and Violet from the visible spectrum.

There are no magic tricks in the eye, if you stare at a relavent shade of green and then look at a white surface, you will see magenta, it is simply a matter of tiring the cones inside the eye to the right amounts to see the complimentary color you want.

November 18, 2011 at 3:48 pm
(5) Chris says:

“I cannot see quite what you mean by our brains magically bringing both ends of the spectrum together? ”

She means that on the spectrum, light and therefore color are a continuous function, they do not wrap around.

But in color theory, it is on a wheel. And that wheel is just the visible spectrum, placed end to end, like a moebius strip, but without the twist.

So, the brain combines red and purple to make magenta, instead of green like she said. Ergo, bringing the ends together.

November 18, 2011 at 6:34 pm
(6) endline says:

“So, the brain combines red and purple to make magenta, instead of green like she said. Ergo, bringing the ends together.”

wait what?

you might want to re-read that.

February 25, 2010 at 4:58 pm
(7) Jimbob says:

Violet is not a mixture of blue and red. Purple is a mixture of blue and red though. Violet is a single color of the visible spectrum in its own right.

November 18, 2011 at 2:15 pm
(8) Noko says:

Being color-blind I never knew what magenta looked like anyway.

November 18, 2011 at 2:49 pm
(9) Tom says:

It’s ok, magenta doesn’t exist, so you aren’t missing anything. It’s all been a lie this whole time.

November 18, 2011 at 2:59 pm
(10) ajinkya rajguru says:

Stare at the black + sign. Magenta dissappears. And is replaced with a circle of green if you jerk your head away

November 18, 2011 at 3:51 pm
(11) Chris says:

What about in chromatic aberration in photography? Because it always occurs in certain color shifts. You can’t change it. So how does it occur there if it’s just something your brain makes up?

November 18, 2011 at 4:30 pm
(12) Syn says:

Because your brain perceives photons the same way as it always does, be it the reflected light off a photograph or transmitted light through a monitor.

From Wikipedia:
“In optics, chromatic aberration (CA, also called achromatism or chromatic distortion) is a type of distortion in which there is a failure of a lens to focus all colors to the same convergence point. It occurs because lenses have a different refractive index for different wavelengths of light (the dispersion of the lens). The refractive index decreases with increasing wavelength.”

Well, there you go. Screw up some of the wavelengths and you’ll get chromatic aberration. You also get different color perceptions as the component wavelengths and their intensities are different via the lens as opposed to what we’d observe.

November 18, 2011 at 5:06 pm
(13) matt bemis says:

dump beet juice into a white sink.

voila…effing magenta organic :)

November 18, 2011 at 5:07 pm
(14) Matt says:

I don’t get it at all. What color on the wheel is magenta? Break it down into something I can use, like Red by red-yellow.

November 18, 2011 at 5:50 pm
(15) Chris says:

It’s between purple and red. Lower left.

November 18, 2011 at 5:27 pm
(16) rikymonty says:

If that visible spectrum is correct i don’t see cyan or yellow in there too. I think that visible spectrum is a little darker that it should be.

November 19, 2011 at 9:24 pm
(17) Mynnia says:

Look between green and red.

November 18, 2011 at 5:29 pm
(18) fuchikoma says:

To clarify this for some people, there are tools called spectrographs – the simplest ones will just show you what colors are in visible light, and have a graph sort of like the top bar in them. If you pointed one at red, you’d see a bright bar (or a peak on a graph) in the red range. If you pointed it at blue, you’d see in in blue, and so on.

If you pointed it at “real” white light, it would indicate all across the spectrum. Different kinds of room lights and things like white LEDs actually only use a subset of this, and you can see what colors they really contain – but it’s “white enough” to fool us. (This is one reason things like white LEDs and fluorescents can make things look kind of creepy or dead – because it’s missing some colors we’re used to.)

If you pointed it at magenta, you would see an indication somewhere in red and somewhere in blue, because the light contains both colors, but magenta itself is not on that scale. That’s basically what it’s saying. Magenta is where red and blue meet – except in nature, they don’t meet at all; they’re on opposite ends of the visible spectrum.

November 18, 2011 at 5:32 pm
(19) artracer says:

“magenta cannot be emitted as a wavelength of light”

That’s ridiculous, all colors are light reflecting or shining into our eyes. If “magenta cannot be emitted as a wavelength of light” then it’d be black

November 18, 2011 at 10:55 pm
(20) joe says:

Yeah you are wrong, try reading the article thoroughly next time. Magenta does not have a specific wavelength, it is our brain’s interpretation of an average of wavelengths emitted by whatever we are looking at.

November 19, 2011 at 12:15 am
(21) Jess says:

The neuron induced perception of color is not merely a reflection of the physical laws of light, it is a biological adaptation to make sense of the input of photons.

November 18, 2011 at 5:40 pm
(22) Russell says:

BBC Horizon did a very good doc on this recently; http://www.youtube.com/watch?v=4b71rT9fU-I is a snippet, I’m sure the rest of it is on there somewhere…

November 18, 2011 at 5:54 pm
(23) Chris says:

Wait, I just noticed a discrepancy that I can’t figure out.

The author claims that if you mix red and green, you get yellow and if you mix violet and red you SHOULD get green. Now, on the spectrum, that makes sense. But on the color wheel that doesn’t follow the same pattern. We’re talking color theory. Isn’t it a well known fact that in art and chemistry, the idea of color and light follow different patterns?

November 18, 2011 at 6:25 pm
(24) Jonathan says:

This article is silly. After telling me that magenta is not emitted as light, the paragraph goes on to say: “Yet magenta exists; you can see it on this color wheel.”. And indeed, there i magenta, on the color wheel, which I am viewing on my monitor that is emitting, oh, what could that be again, LIGHT!

By telling me that I can see magenta on the color wheel as displayed on my monitor, the author essentially refutes her own statement.

November 18, 2011 at 8:22 pm
(25) physics_major says:

You very much misunderstood what the author is saying.
Magenta cannot be emitted as one given frequency of light.
However the brain can interpenetrate a combination of frequencies as magenta, which indeed it does.

November 18, 2011 at 6:29 pm
(26) Ruflus says:

I think Fievel cuts right to the core of the issue.

Vision works quite differently than hearing. Two musical notes played in unison are perceived as a superposition of two sounds but two colors mixed together are perceived as a new, completely different color. The key is precisely perception – how our brain interprets the information delivered by our senses.

There are three types of cone cells in the retina of the eye and each one is sensible to a different part of the light spectrum. To put it simply, there are cone cells for the colors red, green, and blue in the sense that they react predominantly to the reddish, greenish, and blueish portion in the light (http://en.wikipedia.org/wiki/Cone_cell).

A single wavelength of light usually excites two types of cones in different proportions. The color we see is in fact how the brain interprets the ratio of the resulting cone excitations. For example, let us consider that a single-wavelength source emitting orange light excites both reddish and greenish cones equally but the blueish one not at all. If now a second light source would emit a combination of blue and green wavelength such that the three cone types are excited in the same fashion as before, we would perceive the same hue of orange for both sources of light.

When the wavelenght of the light lies near the lower or the upper end of the visible spectrum only one type of cone is excited, either the red one or the blue one. However, we could use a dual-wavelenght light source to excite both red and blue cones simultaneously. The brain then interprets this kind of excitation as “magenta”.

TL;DR: A single-wavelength light source cannot make our brain perceive the color “magenta”. Therefore magenta does not appear in the representation of the visible spectrum at the beginning of the article.

November 18, 2011 at 6:35 pm
(27) Ruflus says:

Edit: “[...] emit a combination of blue and green wavelength [...]” should read “[...] emit a combination of red and green wavelength [...]“. Sorry for the mix-up.

November 19, 2011 at 1:47 pm
(28) kedordu says:

SOUNDS LIKE USELESS USEFUL INFORMATION .

December 28, 2012 at 8:52 am
(29) Vincent says:

Check this out, when you make the whole color spectrum into a complementary colour, you’ll see not only the green as pink, there is yellow on the left-side and cyan on the right-side. I don’t know what it represent, but it’s cool that the color spectrum is complementary to the cmyk.

September 14, 2013 at 6:34 pm
(30) mename says:

alright this is bull. There is a lot of magenta wavelengths or somethin. hoe come i see red red and the mixture red and such and so forth then? y would i see two different things green or whatever thingy? makes no sense.

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