4 ms·

This article gets the colours wrong. Do the red figure example for yourself. If you do it correctly you will clearly see cyan, which is the opposite of red in R

This article gets the colours wrong. Do the red figure example for yourself. If you do it correctly you will clearly see cyan, which is the opposite of red in RGB . It has nothing to do with the "primary colours" of blue and yellow mixing. Basic science facepalm from Smithsonian it seems.

tgv 2y ago
The title is also wrong. It's more "... to show that mediums could fool you easily."
hnbad 2y ago
It's a common mistake thanks to people learning in school that the "primary colors" are red, yellow and blue but the explanation is mostly right otherwise: you see cyan because it's a mix of blue and green, i.e. what you get when you subtract red from white light. Of course human visual perception is a bit more complex than that but the primary mistake here is mixing up RGB and RYB. Quirks of color perception then result in referring to the resulting color as "green" when it clearly contains blue.
- jhbadger 2y ago
  Also, the whole idea that "green" and "blue" are different things is culturally determined -- many languages either use one word that contains the shades English speakers call "blue" and "green" or did so historically before introducing separate words after they were influenced by English or other languages that make the distinction. https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction_in_language https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...
  - KTibow 2y ago
    Doesn't the eye have distinct perceptors for green and blue, or am I missing something?
    - jhbadger 2y ago
      No. There are three types of cone cells (S, M, and L) that are most responsive to various wavelengths of light, but as the picture shows, most "colors" are within the high and low ranges of more than one type of cone. https://en.wikipedia.org/wiki/Cone_cell https://en.wikipedia.org/wiki/Cone_cell
  - jhbadger 2y ago
    For those who downvoted this, did you read the wikipedia entry? Seriously, the idea that many languages don't make a blue/green distinction is a fact.
    - jon_richards 2y ago
      The classic example is Homer's "Wine-dark sea", but it gets a lot more complicated than that https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_color_naming_debate https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_...
GuB-42 2y ago
I think there is more to it than a simple "facepalm". In the modern RGB model, green and blue are primary colors, and mixed together, you get cyan, the opposite of red. So the explanation is generally correct, the only thing wrong is that yellow is considered a primary color instead of green. But look here, and remember the book was published in 1864: https://en.wikipedia.org/wiki/Complementary_colors https://en.wikipedia.org/wiki/Complementary_colors Look at the color wheels of that period and earlier, especially this one: https://commons.wikimedia.org/wiki/File:Color_star-en_(tertiary_names).svg https://commons.wikimedia.org/wiki/File:Color_star-en_(terti... And you see that red is the opposite of green. Why not cyan? I don't know. I guess cyan simply wasn't a well recognized color back then, maybe cyan was called green (a blueish green). Maybe our perception changed with the availability of modern pigments and screens. As for the color you see when trying the illusion, it is even more interesting because it is actually an impossible color! [1] It doesn't correspond to a wavelength of light or a combination thereof, you can only perceive it through an illusion like this one. If we follow the Wikipedia article, and considering that the afterimage appears on a dark background that would be "stygian cyan". Spooky! Again, the theory was probably unknown in 1864. [1] https://en.wikipedia.org/wiki/Impossible_color https://en.wikipedia.org/wiki/Impossible_color
- fmbb 2y ago
  > Why not cyan? I don't know. Because tradition, and the pigments they used. Red, yellow, blue worked great. https://en.wikipedia.org/wiki/Primary_color https://en.wikipedia.org/wiki/Primary_color

tgv 2y ago

The title is also wrong. It's more "... to show that mediums could fool you easily."

hnbad 2y ago

It's a common mistake thanks to people learning in school that the "primary colors" are red, yellow and blue but the explanation is mostly right otherwise: you see cyan because it's a mix of blue and green, i.e. what you get when you subtract red from white light. Of course human visual perception is a bit more complex than that but the primary mistake here is mixing up RGB and RYB. Quirks of color perception then result in referring to the resulting color as "green" when it clearly contains blue.

jhbadger 2y ago
Also, the whole idea that "green" and "blue" are different things is culturally determined -- many languages either use one word that contains the shades English speakers call "blue" and "green" or did so historically before introducing separate words after they were influenced by English or other languages that make the distinction. https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction_in_language https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...
- KTibow 2y ago
  Doesn't the eye have distinct perceptors for green and blue, or am I missing something?
  - jhbadger 2y ago
    No. There are three types of cone cells (S, M, and L) that are most responsive to various wavelengths of light, but as the picture shows, most "colors" are within the high and low ranges of more than one type of cone. https://en.wikipedia.org/wiki/Cone_cell https://en.wikipedia.org/wiki/Cone_cell
- jhbadger 2y ago
  For those who downvoted this, did you read the wikipedia entry? Seriously, the idea that many languages don't make a blue/green distinction is a fact.
  - jon_richards 2y ago
    The classic example is Homer's "Wine-dark sea", but it gets a lot more complicated than that https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_color_naming_debate https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_...

GuB-42 2y ago

I think there is more to it than a simple "facepalm". In the modern RGB model, green and blue are primary colors, and mixed together, you get cyan, the opposite of red. So the explanation is generally correct, the only thing wrong is that yellow is considered a primary color instead of green. But look here, and remember the book was published in 1864: https://en.wikipedia.org/wiki/Complementary_colors https://en.wikipedia.org/wiki/Complementary_colors Look at the color wheels of that period and earlier, especially this one: https://commons.wikimedia.org/wiki/File:Color_star-en_(tertiary_names).svg https://commons.wikimedia.org/wiki/File:Color_star-en_(terti... And you see that red is the opposite of green. Why not cyan? I don't know. I guess cyan simply wasn't a well recognized color back then, maybe cyan was called green (a blueish green). Maybe our perception changed with the availability of modern pigments and screens. As for the color you see when trying the illusion, it is even more interesting because it is actually an impossible color! [1] It doesn't correspond to a wavelength of light or a combination thereof, you can only perceive it through an illusion like this one. If we follow the Wikipedia article, and considering that the afterimage appears on a dark background that would be "stygian cyan". Spooky! Again, the theory was probably unknown in 1864. [1] https://en.wikipedia.org/wiki/Impossible_color https://en.wikipedia.org/wiki/Impossible_color

fmbb 2y ago
> Why not cyan? I don't know. Because tradition, and the pigments they used. Red, yellow, blue worked great. https://en.wikipedia.org/wiki/Primary_color https://en.wikipedia.org/wiki/Primary_color