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.”
I'm not about to tell you with whom I studied, when I was in college, because you can easily find out all about him and where he lived, once he came to America and where he was THE HEAD OF THE ART DEPARTMENT ( two different schools ), which will give you a clue to personal info about me. But...he was very famous, received many different awards in his lifetime,and was awarded prestigious membership positions in several highly regarded artists' organizations.
Here's just ONE example for you to mull over and finally digest: Daniel Smith is a maker of artist grade, quality watercolor paints, their color ROSE OF ULTRAMARINE is in the purple family, is made from TWO different pigments ( PB29 and PV19 ), and is a medium value of purple. PB29 translates into BLUE29, PV19 is a shade of PURPLE; NEITHER contains a pigment that makes black! The numbers that follow the letters, is a description of the one pigment that makes a certain color shade.
The MOST expensive paints are made of a SINGLE PIGMENT and hand poured. And yes, I have an Italian set that contains ONLY single pigment paints! WHY? Because one gets a cleaner, more true color when mixing this kind of paint, BUT, one is still able to get "clean" ( not muddy ) mixes, when using a double pigment paint. And most people who look at a painting done with double pigment paints really won't be able to tell the difference, as long as we're talking about the top quality of artist grade paints.
BS!
White gives you a PHONY shade of pink!
In order to lighten a shade of red, just keep adding water to the paint! The other way, is to use Buff Titanium, which is NOT a white.
I am afraid “Pinky toes” only makes me think of something from Toys are Us like “Ice cream pony”. There is a painting that shows Eos with roses strewn (strewn!) about her feet. See PM
Payne's Grey CAN be made with a black pigment and ultramarine blue; however, it can also be made with other pigments, none of which contain ANY black!
There are also MANY different blacks: LAMP BLACK, IVORY BLACK, MARS BLACK ( this one granulates, so it is really great to work with, as are ALL of the MARS colors ), and NEUTRAL TINT.
I really don't know WHY I keep replying to you, since obviously you 1) do NOT read what I write 2) understand what I write, 3) refuse to believe the FACTS that I present to you.
I've really taken a considerable amount of time and effort to give you detailed FACTUAL information, but I might just as well have been talking to the floor. Hell, I might have gotten a better response from the floor! LOL
So DO NOT reply to me; we're done, finished, over discussing this topic!
“WRONG!Pink is a value of RED, it is NOT a “TINT”, as no such word is used in painting with watercolor or gouache. It is also a stand alone color.”
https://willkempartschool.com/the-hidden-secret-of-colour-mixing/
The hidden secret in paints
The way paint looks when it comes straight out of the tube is usually very different from how it reacts when you start painting. This is especially true with darker colours; the lighter colours such as yellow often behave much as you would expect, hence why a yellow sun always worked at school.
So the primary colours red, blue and yellow alone are not the whole story. Small amounts of other colours are hidden within each pigment – this gives each colour a colour bias.
Colour theory is misleading.
A colour mixing wheel is a great tool; it is handy to have one in your studio for quick reference.
Remembering all the complementary colours when you are starting painting can be tricky.
However, if you take the theory at face value, you are in for hours of frustration when mixing the colour you want.
What is colour bias?
Every single colour has a bias towards another colour.
A blue pigment will have either a red bias or a green bias compared to another blue pigment.
Colour ‘theory’ states that you can mix all 3 secondary colours with the 3 primaries,
However, this will only work if a ‘pure’ primary colour is used.
With paint pigments, you can’t find a ‘pure’ red, for example, that will make both a good orange (when mixed with yellow) and a good purple (when mixed with blue).
This is because the red will have a bias towards either orange or purple due to the chemical impurities foun d within every pigment. (see What are my Acrylic paints made from?)
A red that has an orange bias (Cadmium Red) will mix a bright orange but will not mix a bright purple.
“WRONG!Pink is a value of RED, it is NOT a “TINT”, as no such word is used in painting with watercolor or gouache. It is also a stand alone color.”
All these sites reference tints with watercolors.
Since you want to have the last word, just post WORD to me and I shan't reply.
“YAWN...I hope you learned something; “
If you had an open mind the OP has lots of info to start.
I asked you to NOT reply to me, but you did; so I am asking you, once again, to desist.
“I asked you to NOT reply to me, but you did; so I am asking you, once again, to desist.”
Just replying to your posts. If you don’t want my replies, quit posting sparky comments to me.
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