Posted on 02/03/2025 6:36:50 PM PST by Red Badger
There is something unique about the color purple: Our brain makes it up. So you might just call purple a pigment of our imagination.
It’s also a fascinating example of how the brain creates something beautiful when faced with a systems error.
To understand where purple comes from, we need to know how our eyes and brain work together to perceive color. And that all begins with light.
Light is another term for electromagnetic radiation. Most comes from the sun and travels to Earth in waves. There are many different types of light, which scientists group based on the lengths of those waves. (The wavelength is the distance between one wave peak and the next.) Together, all of those wavelengths make up the electromagnetic spectrum.
Our eyes can’t see most wavelengths, such as the microwaves used to cook food or the ultraviolet light that can burn our skin when we don’t wear sunscreen. We can directly see only a teeny, tiny sliver of the spectrum — just 0.0035 percent! This slice is known as the visible-light spectrum. It spans wavelengths between roughly 350 and 700 nanometers.
The acronym ROYGBIV (pronounced Roy-gee-biv) can be used to remember the order of colors in that visible spectrum: red, orange, yellow, green, blue, indigo and violet. You can see these colors in a rainbow stretching across the sky after a rainstorm or when light shines through a prism. In the visible spectrum, red light has the longest wavelength. Blue and violet are the shortest. Green and yellow sit toward the middle.
Although violet is in the visible spectrum, purple is not. Indeed, violet and purple are not the same color. They look similar, but the way our brain perceives them is very different.
How we see color
Color perception starts in our eyes. The backs of our eyes contain light-sensitive cells called cones. Most people have three types. They’re sometimes called red, green and blue cones because each is most sensitive to one of those colors.
But cones don’t “see” color, notes Zab Johnson. Instead, they detect certain wavelengths of light.
Johnson works at the University of Pennsylvania in Philadelphia. She and other scientists who study how we perceive color prefer to classify cones based on the range of wavelengths they detect: long, mid or short.
So-called red cones detect long wavelengths of light. Green cones respond most strongly to light in the middle of the visible spectrum. Blue cones best detect wavelengths toward the shorter end of the visible spectrum.
When light enters our eyes, the specific combination of cones it activates is like a code. Our brain deciphers that code and then translates it into a color.
Consider light that stimulates long- and mid-wavelength cones but few, if any, short-wavelength cones. Our brain interprets this as orange. When light triggers mostly short-wavelength cones, we see blue or violet. A combination of mid- and short-wavelength cones looks green. Any color within the visible rainbow can be created by a single wavelength of light stimulating a specific combination of cones.
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Notice that the visible spectrum is a gradient. One color gradually shifts into the next. The activity of cones activated by the light also gradually shifts from one type to the next. At the red end of the spectrum, for instance, long-wavelength cones do most of the work. As you move from red to orange, the mid-wavelength cones help more and the long-wavelength cones do less.
In the middle of the rainbow — colors like green and yellow — the mid-wavelength cones are busiest, with help from both long- and short-wavelength cones. At the blue end of the spectrum, short-wavelength cones do most of the work.
But there is no color on the spectrum that’s created by combining long- and short-wavelength cones.
This makes purple a puzzle.
Purple is a mix of red (long) and blue (short) wavelengths. Seeing something that’s purple, such as eggplants or lilacs, stimulates both short- and long-wavelength cones. This confuses the brain. If long-wavelength cones are excited, the color should be red or near to that. If short-wavelength cones are excited, the color should be near to blue.
The problem: Those colors are on opposite ends of the spectrum. How can a color be close to both ends at once?
To cope, the brain improvises. It takes the visible spectrum — usually a straight line — and bends it into a circle. This puts blue and red next to each other.
“Blue and red should be on opposite ends of that linear scale,” Johnson explains. “Yet at some point, blue and red start to come together. And that coming-together point is called purple.”
Our brain now remodels the visible spectrum into a color wheel and pops in a palette of purples — which don’t exist — as a solution to why it’s receiving information from opposite ends of the visible spectrum.
Colors that are part of the visible spectrum are known as spectral colors. It only takes one wavelength of light for our brain to perceive shades of each color. Purple, however, is a nonspectral color. That means it’s made of two wavelengths of light (one long and one short).
This is the difference between violet and purple. Violet is a spectral color — part of the visible spectrum. Purple is a nonspectral color that the brain creates to make sense of confusing information.
Purple thus arises from a unique quirk of how we process light. And it’s a beautiful example of how our brains respond when faced with something out of the norm. But it’s not the only color that deserves our admiration, says Anya Hurlbert.
“All colors are made up by the brain. Full stop,” says this visual scientist at Newcastle University in England. They’re our brain’s way of interpreting signals from our eyes. And they add so much meaning to things we perceive, she says.
“The color of a bruise tells me how old it is. The color of a fruit tells me how ripe it is. The color of a piece of fabric tells me whether it’s been washed many times or it’s fresh off the factory line,” she says. “There’s almost nothing else that starts with something so simple [like a wavelength of light] and ends with something so deep and rich.”
“Of course I know full well what a “shade” is.”
You posted: “Violet is a shade of PURPLE”.
Perhaps you can look up the definition of shade (of color) and explain how you get violet starting with purple.
“which to my way of thinking is fundamental to the argument you guys were having about color combinations.”
Where you came in was a side issue that came up when he said the examples in the article were not purples.
The real issue was he was discounting the science in the article when he had no knowledge of the science.
I didn’t take offense but you replied to me and cc’d nopardons.
That indicated to me you felt the need to educate me so I was curious as to why.
“Looks like someone plagiarized a paper from Wikipedia, and wiki is usually wrong.”
Wrong.
Thanks!
“Pink-toed dawn” seems more evocative than the much more recent “Popsicle Toes”.
Sorry waiter I asked for purple peas, not purple pea pods!
Surely there is somewhere I can get purple peas please.
You may see it, but stare at it long enough and you begin to wonder ...
But then there's this ...
And -- horror of horrors! -- this ...
I guess it's like music. It would make so much sense if there were always a whole step between all the different notes, but God or nature didn't want it that way.
Since you claimed that I don't know what the word "shade" means ( which I do and you don't),why don't you look it up?Because IF I write how to do it, you'll just tell me that I'm wrong. So here's what to do: 1)first look up color wheel 2)then look up secondary colors 3) followed by tertiary colors, the latter being what violet is, and you'll know at least one method of how to do it. But truthfully, you had best look up TWO different color wheels, one using "warm" colors and one using "cool" colors. A third wheel, should you care for even more ways, would be a mixed warm and cool colors color wheel.
Bkmk
“Since you claimed that I don’t know what the word “shade” means ( which I do and you don’t),why don’t you look it up?Because IF I write how to do it, you’ll just tell me that I’m wrong”
A color shade is obtained by adding black. The hue remains the same.
You posted that violet was a shade of purple.
Violet and purple are not the same hue.
Every single color is either a primary, secondary, or tertiary color. Within each color, there are different degrees of saturation ( how vivid or pale it can be ) many of which have a different or two color inclusive names.
There is a cadmium red, cadmium red light, cadmium medium red, etc', each of which becomes a different shade of the color depending upon the amount or lack thereof, of color saturation, which then becomes A SHADE OF THAT COLOR and sometimes then has a different or multiple names.
Then there are such colors as Phylo Blue, Phylo Blue GREEN SHADE, and Phylo Bule RED SHADE, for further examples.
You actually misused the word "HUE". "Family" might be a better term; however that word isn't quite right either, but will do.
Violet, lavender, and purple are members of the same "family". SOME ARE "WARM COLORS, SOME ARE "COOL" COLORS; however, they are distinct colors, have their own names, while still being a "shade" of another/secondary color.
And BLACK is NOT added to darken all colors, it isn't used that way at all; not ever!
“You actually misused the word “HUE”. “
I used it correctly.
“And BLACK is NOT added to darken all colors, it isn’t used that way at all; not ever!”
Black is added to make different shades of a color. A COLOR. The color doesn’t.
Ergo, violet is not a shade of purple as you stated.
There are many different shades and values of the primary color that we call RED: Cadmium Red ( light, medium, and deep ), Scarlet, Carmine, Quinacridone Rose, Alizerin Crimson, Vermilion, and Opera Rose, to name but a few.They're ALL reds, but they're also all different.
Pick one of these and one of MANY different blues, mix together and you WILL get many different and distinct shades of purple.
You can do the same thing with yellow and blue and wind up with many multiples of the color green....all of which have their own distinctive names and shades.
Adding Chinese or Opaque white and you get a so-so pastel, which you can get a much better/cleaner result by just adding more and more water to the original color. OTOH...Buff Titanium, added to a color, WILL give you a better than white added shade.
Color theory is somewhat complicated, I DID attempt to make this easily understood and I hope all of it has helped you to finally "get it".
Perhaps black is used re printing/computer things, but from the beginnings of mankind drawing/painting, it hasn't! And so, mankind has seen these colors SANS black being added for millennia!
And you are still, stubbornly, misusing the word "HUE"!
“BLACK IS NEVER, NOT EVER, ADDED TO A COLOR TO DARKEN IT”
Black is added to a color to produce a darker shade of the SAME color.
“SHADES
A Shade is simply any color with black added.”
https://studioq.myportfolio.com/color-theory
“There are many different shades and values of the primary color that we call RED: Cadmium Red ( light, medium, and deep ), Scarlet, Carmine, Quinacridone Rose, Alizerin Crimson, Vermilion, and Opera Rose, to name but a few.They’re ALL reds, but they’re also all different.”
A shade of a color is the SAME color. It is just darker due to the addition of black.
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Stephen Westland
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Professor of Colour Science at University of Leeds
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Nov 6
Part of the problem here is when we use words loosely. For example, I don’t really know what you mean by shade.
Technically a shade is a colour produced when mixed a pure colour with black.
But some people use shade as a synonym for colour. And some people use shade as a synonym for hue. And some people use hue as a synonym for colour.
But, in short, when we mix two colours we don’t only get one colour, we get a range of colours depending on the proportion in which we mix the two colours.
If you did, then the vast majority of what I posted is repeated on there! So.....you're using a nobody I've never heard of ( not that's I've heard of EVERY single artist world wide, for millennia ) who states what I stated, EXCEPT for the black to make colors darker. LOL
I am NOT tech savvy at all, so can't do links, but I can give you at least 30 different artists, on line, who ALL disavow adding black to darken ANY and ALL colors! And most of them are professional painters, who have been earning their living, doing many different kinds of art ( cards, invitations, paintings, portraits, book illustrations ) for far longer than they've been on YouTube.
I have been painting almost my entire life and yes, I did have classes in watercolor, sculpting, and oils. And adding black to darken a color, has ALWAYS been a NO NO, from every single source I have learned from; starting from when I was 6 years old!
There ARE many other ways to "darken" a color!
Okay, here's a VERY simple question for YOU to answer, anyway that you are able to: WHAT SPECIFIC COLOR OR ITEM, WOULD BE USED TO MAKE PALE PINK? And do bear in mind that PINK is a shade/value of a different color.
“I am NOT tech savvy at all, so can’t do links, but I can give you at least 30 different artists, on line, who ALL disavow adding black to darken ANY and ALL colors!”
That is because black pigments are not true black.
You have to compensate for that in your mixing.
But that still doesn’t change the technical definition of shade.
Ergo, violet is not a shade of purple.
“I am NOT tech savvy at all, so can’t do links, but I can give you at least 30 different artists, on line, who ALL disavow adding black to darken ANY and ALL colors!”
And for each I can give you one that swears to using black.
“Okay, here’s a VERY simple question for YOU to answer, anyway that you are able to: WHAT SPECIFIC COLOR OR ITEM, WOULD BE USED TO MAKE PALE PINK? And do bear in mind that PINK is a shade/value of a different color.”
Pink is a red tint. Tints are made by adding white to to a color.
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