Welcome to Interesting If True, the podcast that is kinda drunk right now, thanks mimosas!

I’m your host this week, Shea, and with me is the indomitable Aaron:

I’m Aaron, and I brought my amazing, technicolor, dream-mimosa.

Imposi-Color! Better than the burger.

So, this week I was sitting in a high school Space Science class this week with one of my students and we were learning about the electromagnetic spectrum, a cool fact only .0035% of the spectrum is visible light. We eventually got on the subject of human eyes and the photoreceptors we have, humans have rods and cones. Quick science lesson, rods are responsible for low light vision and don’t do color, whereas cones are in charge of the color with cones of red, blue, and green. If you remember, the rods and cones in my eyes are lazy as hell and don’t really work, hence my complete color blindness and inability to see at night. Regardless of my shitty vision, some of these facts got me thinking about color and wondering if we all see the same colors and how there is no real way to know, but what we do know is your eyes and brain like to invent a lot of colors you see.

While falling down a rabbit hole filled with colors I can’t see I learned about Impossible Colors! These are colors our eyes simply cannot process because of the antagonistic way our cones work, for instance, “red-green” or “yellow-blue.” There is some pretty crazy stuff about color, my colorblind ass is going to attempt to teach you today.

We take the way we see the world for granted. But our experience of the world is shaped in part by our visual system—which is both extremely complex and limited. Impossible colors, which are sometimes called non-physical colors, are a great reminder to not consider our perception of the visual world the only possible experience.

I want you to try and imagine reddish-green — not the dull brown you get when you mix the two pigments, but rather a color that is somewhat like red and somewhat like green. Or, instead, try to picture yellowish blue — not green, but a hue similar to both yellow and blue.

I can’t, but that could be because I forgot what those colors look like but I have a feeling most of you are having a hard time doing it too. Even though those colors exist, you’ve probably never seen them. Red-green and yellow-blue are the so-called “impossible colors.” Composed of pairs of hues whose light frequencies automatically cancel each other out in the human eye, they’re supposed to be impossible to see simultaneously.

The human eye has three types of cone cells that register color and work in an antagonistic fashion:

Blue versus yellow

Red versus green

Light versus dark

There is overlap between the wavelengths of light covered by the cone cells, so you see more than just blue, yellow, red, and green. White, for example, is not a wavelength of light, yet the human eye perceives it as a mixture of different spectral colors. Because of the opponent process, you can’t see both blue and yellow at the same time, nor red and green. I’d like to explain the opponent process but it is way above my paygrade and I’m a bit too dumb to figure it out on my own, what I stole from Healthline.com was “the opponent-process theory suggests that the way humans perceive colors is controlled by three opposing systems.” So, you’re welcome.

To wrap my head around this I need a bit more understanding of color itself. The colors we see are only reflections of light with different wavelengths. We see colors when the reflected light from an object is detected by millions of color-sensing cells in our retina known as cones. For example, orange fruit is not inherently orange. When light passes through the orange’s surface, certain wavelengths are absorbed and others are reflected back and sensed by cones. These cones send electrical signals to our brain that process the data into a recognizable color, in this case, orange. Orange light is on the lower end of the spectrum with wavelengths of 630 nanometers, red is at the bottom of the spectrum with wavelengths of 665 nm, and violet is at the top of our visual spectrum at 400 nm.

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So we talked about one of the types of impossible colors: red/green blue/yellow. They are impossible colors but also called forbidden colors. There are two other types: Chimerical colors and Imaginary colors.

Another type of imaginary color is a chimerical color. A chimerical color is seen by looking at a color until the cone cells are fatigued and then looking at a different color. This produces an afterimage perceived by the brain, not the eyes.

<figure class="wp-block-image alignwide size-full"><figcaption>Look directly at the + in the center for 20 to 30 seconds.</figcaption></figure>

You can see impossible colors if you’re good at crossing your eyes but chimerical colors are a lot easier to see just by tiring out your eyes a bit. If you go to our website I have a cool gif that will help you see some new colors. Stare at a cross on a dot and when it shifts to black, white, or orange your eyes will have an after image with a new color.

Chimerical colors don’t appear within the color space of human vision. As the name suggests, they are a construct of the mind. They can be created by inducing a natural process of the eye called color fatigue. If you stare at a color for a long time your eye will temporarily displace the colorspace by the opposing color. So if you stare at yellow, then black, for a short time you will perceive that black to contain blue. The color you are seeing is out of the range of visible colors. It is a pitch-black blue; thus it is deemed an impossible color. There are three types of chimeric colors: Hyperbolic, Luminous, and Stygian.

As the name suggests, hyperbolic colors are normal colors but are exaggerated beyond what is physically possible for our eyes to perceive. If you stare at bright cyan and then view the orange afterimage on an orange background, you see “hyperbolic orange.” If my gif is embedded properly you can see hyperbolic orange in the first dot, orange.

Luminous colors are simultaneously pure white and “glow” another color. An example is “self-luminous red,” which may be seen by staring at green and then looking at white. When green cones are fatigued, the after-image is red. Looking at white causes the red to appear brighter than white, as if it was glowing.

Our last type of chimeric color is the coolest name, in my opinion, stygian colors. These impossible colors are similar to luminous but instead of looking at white for an after image you look at black. Stygian colors are dark and supersaturated. For example, “stygian blue” may be seen by staring at bright yellow and then looking at black. The normal afterimage is dark blue. When viewed against black, the resulting blue is as dark as black, yet colored. Stygian colors appear on black because certain neurons only fire signals in the dark.

The word stygian means of, or pertaining to Hades or the River Styx, so metal! The river Styx was described as being blue, yet as dark as black.

Imaginary colors. “Real” colors are colors that can be produced by a physical light source. Although “imaginary” colors are outside this spectrum and no physical object can have an imaginary color, they are often found in the mathematical descriptions that define color spaces. An example of imaginary color is “hyper-green.”

To be honest, imaginary colors confuse me the most and I can’t find a ton of information on them and I’m not good enough at math to even wrap my head around them. But what I gather is some wavelengths are a color that exists but nothing happens naturally in nature.

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• Awesome graphic I found at nesslabs.com


• http://www.luniere.com/2014/03/01/hyperbolic-orange-and-the-river-to-hell/


• https://en.wikipedia.org/wiki/Impossible_color


• https://interestingengineering.com/impossible-colors-and-how-to-train-your-eyes-to-see-them


• https://www.livescience.com/17948-red-green-blue-yellow-stunning-colors.html

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