Never Fear, Ladies, Pink is Here to Stay

By now it’s pretty likely you’ve heard about the NPR blog post in which Robert Krulwich worries that pink may not really be a color. Is there cause for concern, or is it just a misunderstanding of how we define colors? 

First, we have to understand the difference between spectral (additive) colors and pigments (subtractive colors). Spectral colors are the light waves emitted from a source such as the sun, while pigment colors are mixed to affect what we see when light reflects off an object. Our sun emits white light, which is a mix of all the colors of light mixed together. When this light passes through a prism, such as water drops in the atmosphere after a rainstorm, the light is scattered into its component wavelengths, which our eyes interpret as different colors: red, orange, yellow, green, blue, indigo, and violet.

prism scattering white light into its components
White light scattering into a rainbow

Our sun emits all these colors on its own, which is why we’re able to see white objects. Other light sources such as computer monitors use an additive process to create the colors we see. For example, the yellow and orange stripes you see coming from the prism above aren’t actually orange or yellow at all. Your monitor is lighting up red and green pixels that are so close together than your eyes blend them together to make a new color. In fact, every single color on your monitor is made up of a mix of red, green, and blue light in different concentrations. Additive light is also used in theatrical lighting. While it may appear that actors on stage are under white light, this is rarely the case because pure white light is very harsh and, due to the limitations of the filaments in the light bulbs used, starts turning orange-y if the lights are dimmed at all. For “white” light, different colored gels are placed on the light fixtures and the pools of light on the stage are arranged so that the different colors remix to make white. Usually, this means paired amber and blue lights aimed at the same spots, repeated enough times to cover the stage. In additive light, white is the presence of all colors, while black is the absence of color. There is no way to project true gray light since putting a gray filter on a light screens out every wavelength equally to dim the light; this is why nighttime scenes are typically lit in blues.

red, green, and blue lights combining to form other colors
Example of RGB mixing with theater lights

When most of us think about how colors are mixed, we’re thinking of pigments. Red, yellow, and blue are the primary colors that mix in equal proportions to form the secondary colors orange, green, and purple, and then in different proportions form countless other colors. Mix all of three primaries together, you get black; take them all away, white. Adding black pigment to any color makes a shade (think midnight blue, or brown as a shade of orange), while adding white pigment (or thinning a medium like watercolors with extra water and applying it to a white surface) makes a tint (pink being the one that pops to mind first, but really all pastels). Pigments absorb certain wavelengths of light and reflect others; it’s that reflection that our eyes pick up and read as a particular color. This method of color mixing is used in painting, color photo development, and other art forms.

color wheel with secondary and tertiary colors
Grab some fingerpaints and try this out yourself!

In printing, however, a different subtractive process is used to apply pigments to paper or other media. In contrast to the red, yellow, blue mixing we just discussed, printing generally uses CMYK (cyan, magenta, yellow, and black) in different concentrations. Technically, cyan, magenta, and yellow form black when all mixed together, but it’s much cheaper to have a separate print cartridge of black ink rather than deplete all three color cartridges. This process only works properly on white paper since it’s impossible to print the color white using CMYK; white spaces are left unprinted so the background color shows.

diagram of subtractive color mixing
Cyan, Magenta, and Yellow make all those colors? Cool!

Krulwich is correct when he states that “pink is not a real wavelength of light,” but then again, neither are most colors. Pink is how our eyes interpret a mixture of wavelengths that include red, violet, and maybe some indigo or blue if it’s a really dark fuchsia or some orange or yellow for a peachy pink. There’s no purple wavelength either since it’s a mix of red and blue pigment; the light in the rainbow is violet. But as we’ve seen, pure wavelengths of light are only one tiny way of defining the colors around us.

Published by

[E] Hillary

Hillary is a giant nerd and former Mathlete. She once read large swaths of "Why Evolution is True" and a geology book aloud to her infant daughter, in the hopes of a) instilling a love of science in her from a very young age and b) boring her to sleep. After escaping the wilds of Waco, Texas and spending the next decade in NYC, she currently lives in upstate New York, where she misses being able to get decent pizza and Chinese takeout delivered to her house. She lost on Jeopardy.

17 thoughts on “Never Fear, Ladies, Pink is Here to Stay”

  1. I would like to restate that my “Taste the rainbow” album on Facebook, wherein I made my kid eat different colored things and then did a  ROY G BIV series also didn’t include pink.  And it was the peak of my parenting career.

    Which has nothing to do with anything, but I love this article.

  2. Also there’s a lot of linguistic work on the semantics of colour terms – not all languages have the same set of colour terms with the same meanings. A good equivalent of ‘pink’ might not exist in a language but it doesn’t mean the colour doesn’t exist or that speakers of that language can’t perceive it.

    1. My favorite thing to think about on this subject is the opposite: what about places that have multiple colors for words that we only have one word for.  Blue is blue, whether it is light or dark, to me.  To my husband, light blue and dark blue are two separate colors, like pink and red are for me.  MIND=BLOWN.

  3. Wrong place, again.

    ETA a real comment:

    From the original blog post: It turns out (and this is not a new development, it’s just something I didn’t know), there is no pink in a rainbow.


    There’s this recurring problem where journalists, no matter how well-educated, seem not to know a damn thing about basic science or math (or rainbow-related factoids familiar to many small children).

    Then there are, where applicable, their erstwhile standards. For example, Robert Krulwich is not the kind of guy I would expect to just slap up a blog piece on a topic he apparently knows nothing about without doing any research. I am going to have to assume he thought elementary-level physics too arcane to Google.

    Are there any journalists who aren’t comfortable flubbing basic science? This is depressing.

    All that aside, nice article. Everyone who reads it will know more about the abstruse magicks of the visible spectrum than many award-winning journalists.

    1. Thanks! His assumption that just because he didn’t know something really fucking basic that no one else would know it either annoyed the crap out of me. My 2-year old sings the rainbow song from Sid the Science Kid all the time; even she knows there’s no pink in a rainbow (though it took a while to convince her she didn’t need to say “blue, purple, indigo, violet”). Science journalism depresses me.

    2. Really???  I thought everyone knew about Roy G. Biv.  Like – that it was a thing.  The way people learn the colors of the rainbow.  My sister abhors science – she shuts down whenever I start talking science – and she knows Roy G. Biv.  Come on.

  4. Along with tints and shades, there is a third option of tones. You get tones by adding grey to a color. This neither lightens nor darkens it, but desaturates it (makes it less bright). Think of sage greens or slate blues.

    Also, Protip from an art school grad, if you ever tried out that whole get every color from only three tubes of paint trick and gotten horrible muddy results, it was likely not you but your paint. If you go shopping for artists paints you will likely see two different versions of the same color shelved next to each other. One will have the color name and the other will have the color name with hue at the end. The hue will be miles cheeper. This is because the first is a pure pigment paint and the other is an amalgam of cheeper pigments that approximate the same color. So Cadmium Yellow has nothing but yellow cadmium in it. Cadmium Yellow Hue is a mix of pigments that end up cadmium yellow colored. If all the tubes are the same price then they are hues, not pure pigments. Pigments vary in cost from color to color and the paint tubes will reflect that. Now when you go to mix colors with hue paints, sometimes the pigment mixtures react to each other in less than predictable ways. Or in other words they make a big ass mess.

      1. Actually, full disclosure, you will probably still need six tubes of paint (well eight if you count titanium white and ivory black). There aren’t really any pigments that match true chromatic red, blue, or yellow. Most are shifted either to the warmer or cooler side of the spectrum. Yellow is probably the hardest one to distinguish this on because it’s so bright it’s hard to detect subtle shifts in the color, but it’s pretty obvious in reds and blues. Cadmium red is more to the orange side, Magenta more to the purple. So you’ll need a warm and a cool version of each color and to get the pure primary you’d have to mix them together.

  5. I want to throw something at that original blog post. It’s like it’s picking on one particular color, even though others should be demoted as well according to his strict criteria…and it just so happens the one he picks on happens to be the “feminine” color in Euro-American circles.

    1. To be fair, he picked on pink because the Minute Physics video picked on it. I probably should have included it but since it was at the link anyway and massively annoyed me for some reason, I left it out. But yeah, there are any number of colors that don’t fall on the spectrum of visible light and it was weird to single out pink. I blame the patriarchy. :)

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