See “true cyan”!

February 10, 2022 • 2:00 pm

This video supposedly enables you to see a color that apparently can’t be reproduced on the screen: “true cyan“, a color between green and blue.   Turn on the sound, put your face about a foot from the screen, and then fix your gaze on the white dot in the center for the duration of the soundtrack. When the music ends, close your eyes, and with luck you’ll have an afterimage of the “true cyan” color. It is a lovely blue.

This source gives a bit more information:

True cyan illusion

Even though the human eye is incredibly sophisticated, there are times when you can trick your brain into seeing things that completely bizarre. For example, we know that there are three primary colours – red, yellow and blue – and all other colours are formed by mixing them. There are still shades of colour that often occur naturally and are difficult to produce on electronic screens.

What if we tell you there’s a colour known as true cyan, which is a greenish-blue pigment and is difficult to capture on television and is often diluted to a lesser form?

An optical illusion posted on social media has left netizens amazed as they could see the dazzling green-blue pigment.

TikTok user Kate Bacon posted a video telling people that would show them a colour that they’ve probably never seen before. She said, “It’s called true cyan, and most TVs and monitors aren’t capable of producing this pigment.”

Viewers are shown a red circle with a white dot against a blue background. Kate says that you need to stare at the white dot for at least 30 seconds, but the longer the better. Afterwards, if you close your eyes really tightly, you should see a ‘glowing orb’ in the colour of true cyan.

A similar video available on Youtube instructs the viewer to stare at the white dot in the centre of the red circle as the camera slowly pans out. By the time the video ends, the viewer will be able to see the true cyan colour appear like a halo around the red circle.

30 thoughts on “See “true cyan”!

  1. I see the cyan and also now I feel that I must join a collective to obtain cyan for the printers of the world. Do you think I was brain washed by the printers to do their bidding?

  2. What happens there, staring at the red dot exhausts the red photopsin (L = long wavelength) in the cone cells, which then allows to experience stimulation of the other two (S-Short and M-Medium), producing cyan.

    1. And what would happen if we reversed it and the red dot were a blue dot surrounded by red. Would we see a “true red”.

        1. Interesting…not the same effect I thought, but intriguing nonetheless. I love me eyes as they seem directly connected to me brain… colors are like taste.

  3. Here’s my question, when the true cyan appears, are you actually seeing it? Evidently not, because it’s not actually ‘out there’ to be seen. Would it be correct to say that you are ‘perceiving’ it? Or is it totally being invented by your brain? Or, even, is it totally being invented by some non-physiological apparatus of consciousness, whatever that may be?

    Obviously, the true cyan as such is not in the brain. That is, there’s no place in the physical brain where you could find the true cyan color in amongst the gray and white, etc. So where is it?

    1. Special molecules, called photopsins, in special cone cells for colour vision in your retina react to photons of a certain wavelength hitting them, S, M and L — for short, medium and long waves. Their response curve matches Red (R), Green (M) and Blue (S) wavelengths of light. This releases electrons, which then race into your brain, in specific patterns. In addition, you have other cells, called rods, which respond mostly to a green-blueish light spectrum (and another molecule called rhodopsin). These photons are the same, but here you perceive this as colourless brightness (incidentially, colours of foliage and sky) that gets mixed in. Your brain evolved to make sense of these firing patterns, which is what we call vision. The colours are what philosophers call “qualia” and are subjective sensations.

      1. Why are light primaries red green blue, but pigment primaries are red blue yellow. I know pigments are reflected light, and the object is absorbing all but the color we see, but I don’t know why that changes the primaries.

        1. I don’t know what you mean by “changes the primaries”, but otherwise you already have the answer. Since white light with a wide spectrum falls on the ink, you can manipulate the colour by absorbing a certain part, leaving the remaining to reflect and stimulate your photovision. By printing magenta pigment and yellow, the inks absorbs this spectrum, and the remaining red wavelengths can hit your eye.

      2. The nervous connection between photoreceptors and the visual cortex of the brain is complex, with several cells and synapses involved, but at no point do released electrons race into the brain.

  4. I can’t imagine any reason why computer monitors can’t reproduce this “true cyan”. Since I am watching this illusion on my computer screen that seems wrong on its face. If I am seeing true cyan and its not on my screen, where is it? I suspect this color comes from our receptors being selectively exhausted by the bright red circle. So the blue we see when it is removed is produced in our brains. But that’s true for everything we see. What exactly is true color in this context?

  5. Did anybody else suddenly feel compelled to walk outside wearing a cardboard box and yell “I need pickles for my jacuzzi!”? Or was it just me?

    1. I could see the cyan all throughout depending on how I adjusted my gaze, something like manipulated stereo vision, if that is how it is described. There used to be popular posters with images inside if you could only adjust your gaze just so. When I let my eyes do what they would do to see into those posters, I saw the cyan in various circular positions. It was much more prominent with my eyes open than closed at the end, but I could detect a reflection of the cyan in my mind after with eyes shut.

      Regardless, now I’m dizzy! I hate carnival rides and am easily carsick. We just did something like whipping my head around.

      1. I also saw bits of Cyan throughout, especially when I blinked but at other times as well, it seemed to shimmer around the outside of the circle.

        Many thanks for posting this as it is a great end to a fantastic week in North Wales where I have been on a Welsh language course. My brain is now well and truly pickled 🙂

  6. I used to do color calibration on industrial scanners and printers back before everything became more standardized, and have never heard the term “true cyan”; I think it’s a click-bait term. And if “true cyan” = (white – “true red”), this isn’t it since the red in the video has a slight blue component (<1%).

    Also, colors which can't be displayed on a computer monitor are nothing new; lasers, florescence, etc, can produce those colors.

    If you want to imagine where this "true cyan" lies on a color gamut chart, in the “Typical CRT gamut” picture, imagine drawing a line from the red corner of the colored triangle, thru the midpoint of the blue-green axis…and into the gray area, which the monitor can’t display.

    I suppose one could do the same thing to produce a “true magenta” or “true yellow” which can’t be displayed.

    1. Very good

      Yes, I’ve read/heard about magenta – a big deal is made in many videos, maybe writing. Seems to play upon imprecise / sloppy use of language –

      “see” “perceive” “pigment” “primary colors” “color mixing” “wavelength” “experience” etc., as noted here.

      Also comes to mind : The Dress.

  7. Sherwin-Williams once had a color, Uranian Blue (not Ukranian Blue!) that was just like the cyan that I saw. I remember Uranian Blue because my mother picked it for the trim on the house I grew up in. In many, many years I only ever saw a couple other houses wearing that color.

  8. I’ve seen this color before (I think) by saturating blues in photoshop. It’s neat how the optical illusion (or whatever you call it) was able to produce the color by messing with my brain.

  9. That TikTok claim is complete nonsense. The 3 primary colors for additive color systems (i.e. light) are Red Green, and Blue. The 3 primary colors for subtractive color (i.e. pigment/paint) systems are Cyan, Magenta and Yellow. The author of that claim (which is way too often incorrectly taught in grade school) has called Magenta Red and Cyan Blue. Any university level physics (and even any better high school) course will confirm this.

    Since light is additive:
    Red+Green=Yellow (Orange is an excess Red form of Yellow)
    Red+Blue=Magenta (which is nonspectral, since no single wavelengh exists for it)
    Good color monitors can generate much wider color gamuts than pigments allow.

    Pigments and paints are subtractive:
    Cyna+Magenta=Blue (Blue is common to both)
    Yellow+Cyan=Green (Green is commpn to both)
    Yellow+Cyan=Green (Green is common to both)

    Some color wheels:

    Also see: (I actively used an older edition decades ago in assisting human color vision studies and this has been well known since at least the 1970’s and the earliest color TV CIE standard was available in the early 1930’s).

    “It’s called true cyan, and most TVs and monitors aren’t capable of producing this pigment.” Since color monitors and TVs use light, they cannot produce any “pigment”. The speaker is obviously not well informed (to put it politely as I can). YouTube and TikTok, among many other sources of nonsense) are all to often unreliable. Good color monitors can create a wider color gamet than pigment based subtractive processes, so the TikTox claimant has that backwards as well. (Also see my “hyperphysics” reference above).

    What the TikTok demo is doing is fatiguing two of the 3 types of color cones in your eyes (assuming no color-blind or tetrachromatic* viewers) with a red-orange color. Hence you perceive a blue(ish) color after image since those color cones were affected very little.

    Of course the human visual system is easily fooled:

    Here are a few links to a bunch of worthless “free-energy” machines on YouTube, for example:
    etc. There are at least hundreds if not thousands of links to these totally nonsensical machines.

    *NOTE: Tetrachromacy is quite rare and limited to females in humans since the human male Y chromosome is degenerate.

    1. I’m enjoying the debunking on thread so much – lots of great resources to check out.

      I wonder if the color blind can weigh in on this – I mean, it’s complex enough to try putting a finger on this – what about color blind phenomena?

  10. There are multiple types of color blindness, which are far more common in human males than human females. Color blindness in humans is a recessive gene trait. The human male only needs one defective X gene to achieve some type of color blindness (due to the degenerate Y chromosome not having any matching color gene for “backup”) while a human female would need to have defective genes on 2 X chromosomes to exhibit color blindness. (the ratio between male and female color blindness in humans is about 20:1, respectively.

    There are multiple types of color blindness, Dichromacy is exhibited when one type of color sensing cone is missing so that only 2 of the normal 3 color sensing cones are present. The most common form of this is the inability to distinguish between green and red since the green sensing cones are missing. Monocromacy occurs when there is a complete lack of ability to see color and only light intensity can be perceived. Imagine removing all color like in a black and white photograph (remember those) and that is what a completely monochromatic color blind person would see.

    Note that there are specialized glasses available to help dichromats distinguish between green and red. This does not restore full trichromacy but it greatly assists dichromates with seeing greater red and green color differences. It actually does his by “notching out” (removing) a part of the color spectrum between red and green.

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