Correct. Initially, Newton didn’t have indigo in his list for the visible spectrum, but he wanted seven colors instead of six because it matched up with the number of notes in music (and because he liked the number). So at some point there was discussion of removing indigo entirely because it’s kinda just a shade between blue and violet that the human eye just isn’t as good at distinguishing compared to the other colors. But the neat thing is that what people back in Newton’s time called blue and indigo is more akin to what we today call cyan and blue (they know this by looking at his labeled drawings of the light scattered by prisims). Now the spectral colors are: red, orange, yellow, green, cyan, blue, and violet.
Purple, the color directly between red and blue, is a creation of your mind interpreting a band of light that triggers your red and blue sensing nerves, but no green is sensed. The actual band of light we can see goes from red to green to blue. Purple doesn’t fall between those colors, meaning it wouldn’t be included in a rainbow, and isn’t any “pure” light you could see, since it doesn’t fall on the spectrum.
Essentially, any time you see purple, you’re seeing two different frequencies of light that your mind interprets as a single frequency.
This is 100% incorrect. Not in terms of science, but in terms of a qualifier of what a colour is. Just because a colour doesn’t exist on the rainbow spectrum, doesn’t mean it’s not an “actual colour”.
What you’re referring to is the definition of colour specifically by physics. There are other professional fields and areas of science that use different qualifiers for colour. I work with color everyday and I can with certainty say that purple, pink, rust, teal, and sky blue are all colours.
Kind of like how different fields have different definitions of entropy or different cultures have different names for snow. It’s all dependent on the framework you use and ignoring every other framework is wrong.
Would this not disqualify any mixed color? We only have receptors for three colors, and if we’re arguing that purple isn’t a color because it’s actually two mixed together, that should also mean colors like orange, yellow, cyan, magenta, atc are also not colors by that definition right?
ah a similar explanation to why yellow is not an actual colour either
the silly explanation that has no effect on how we perceive, use, or think about colour. sigh why are the people responsible for those studies calling those colours not real? Why not just colours resulting from mixing other colours like the artists have done since the invention of paint?
Sorry for the confusion. Yellow is a single wavelength of light. We perceive it with the green and red receptors in our eyes, but it is a single wavelength. Purple isn’t a single wavelength, but two that are being interpreted as a color.
and that is why i didn’t say the same explanation, but similar
both, in my opinion, suffer from the clickbait disease “YOU CAN’T SEE YELLOW 😱” (directly, because to see it you use two light receptors combined) “PURPLE DOESN’T EXIST 😱” (as a single wavelength colour because as opposed to the other colours of the rainbow it uses a combination of red and blue wavelengths)
i don’t blame you for either of course, i’m just expressing my general annoyance with the phrasing of both science facts
What is violet at the end of the visible spectrum, then? We call the higher wavelength stuff ultraviolet, and violet looks purple to me, so I’m having trouble reconciling this stuff with what you’re saying.
We call it that but our eyes see the far end frequency as a colour that only very slightly activates blue sensitive cone receptors and no others. For red sensitive cones there is a slight bump in the high end frequencies also that makes it possible for them to look violet as it activates the blue sensitive and a bit of red sensitive receptors but a much purpler purple is made by combining high and low frequencies.
There is evidence to show that violet does actually weakly activates red cones too. This is because the violet light starts creeping up to double the frequency of the lower end of the red sensitivity, and so it can actually successfully activate it very weakly. There are other factors that can lessen or even fully negate that effect though, it’s all kind of fuzzy.
Your definition of color is based only on human perception? Is purple a color for a mantis shrimp?
Edit: I guess not in a pure sense because it’s still two wavelengths of light. Perhaps a mantis shrimp can detect a totally different wavelength and sees it as “purple” or something.
Now I’m thinking about how we don’t know how other humans interpret colors. Like what I see as red, you may see as blue. Ugh.
Definition I’m using is any color that can be expressed as a single wavelength of light. Purple cannot be, since it’s actually two wavelengths simultaneously.
Is it a skittles reference or is it a reference to purple not being an actual color and thus not a part of the rainbow?
I believe it’s indigo not purple there.
Correct. Initially, Newton didn’t have indigo in his list for the visible spectrum, but he wanted seven colors instead of six because it matched up with the number of notes in music (and because he liked the number). So at some point there was discussion of removing indigo entirely because it’s kinda just a shade between blue and violet that the human eye just isn’t as good at distinguishing compared to the other colors. But the neat thing is that what people back in Newton’s time called blue and indigo is more akin to what we today call cyan and blue (they know this by looking at his labeled drawings of the light scattered by prisims). Now the spectral colors are: red, orange, yellow, green, cyan, blue, and violet.
the heck do you mean purple is not an actual colour??
Don’t let them pee on your Cheerios. Purple is a color, just like magenta, pink, cyan, brown, and all the other “not in the rainbow/ROYGBIV” colors.
Gatekeeping colors, I tell ya. Don’t let 'em get you burnt sienna with rage.
Purple, the color directly between red and blue, is a creation of your mind interpreting a band of light that triggers your red and blue sensing nerves, but no green is sensed. The actual band of light we can see goes from red to green to blue. Purple doesn’t fall between those colors, meaning it wouldn’t be included in a rainbow, and isn’t any “pure” light you could see, since it doesn’t fall on the spectrum.
Essentially, any time you see purple, you’re seeing two different frequencies of light that your mind interprets as a single frequency.
This is 100% incorrect. Not in terms of science, but in terms of a qualifier of what a colour is. Just because a colour doesn’t exist on the rainbow spectrum, doesn’t mean it’s not an “actual colour”.
What you’re referring to is the definition of colour specifically by physics. There are other professional fields and areas of science that use different qualifiers for colour. I work with color everyday and I can with certainty say that purple, pink, rust, teal, and sky blue are all colours.
Kind of like how different fields have different definitions of entropy or different cultures have different names for snow. It’s all dependent on the framework you use and ignoring every other framework is wrong.
Would this not disqualify any mixed color? We only have receptors for three colors, and if we’re arguing that purple isn’t a color because it’s actually two mixed together, that should also mean colors like orange, yellow, cyan, magenta, atc are also not colors by that definition right?
ah a similar explanation to why yellow is not an actual colour either
the silly explanation that has no effect on how we perceive, use, or think about colour. sigh why are the people responsible for those studies calling those colours not real? Why not just colours resulting from mixing other colours like the artists have done since the invention of paint?
Sorry for the confusion. Yellow is a single wavelength of light. We perceive it with the green and red receptors in our eyes, but it is a single wavelength. Purple isn’t a single wavelength, but two that are being interpreted as a color.
That was the distinction I was calling out.
and that is why i didn’t say the same explanation, but similar
both, in my opinion, suffer from the clickbait disease “YOU CAN’T SEE YELLOW 😱” (directly, because to see it you use two light receptors combined) “PURPLE DOESN’T EXIST 😱” (as a single wavelength colour because as opposed to the other colours of the rainbow it uses a combination of red and blue wavelengths)
i don’t blame you for either of course, i’m just expressing my general annoyance with the phrasing of both science facts
What is violet at the end of the visible spectrum, then? We call the higher wavelength stuff ultraviolet, and violet looks purple to me, so I’m having trouble reconciling this stuff with what you’re saying.
Violet and purple are distinct terms here.
We call it that but our eyes see the far end frequency as a colour that only very slightly activates blue sensitive cone receptors and no others. For red sensitive cones there is a slight bump in the high end frequencies also that makes it possible for them to look violet as it activates the blue sensitive and a bit of red sensitive receptors but a much purpler purple is made by combining high and low frequencies.
https://www.researchgate.net/figure/Normalized-spectral-sensitivity-of-retinal-rod-and-cone-cells_fig7_265155524
There is evidence to show that violet does actually weakly activates red cones too. This is because the violet light starts creeping up to double the frequency of the lower end of the red sensitivity, and so it can actually successfully activate it very weakly. There are other factors that can lessen or even fully negate that effect though, it’s all kind of fuzzy.
Your definition of color is based only on human perception? Is purple a color for a mantis shrimp?
Edit: I guess not in a pure sense because it’s still two wavelengths of light. Perhaps a mantis shrimp can detect a totally different wavelength and sees it as “purple” or something.
Now I’m thinking about how we don’t know how other humans interpret colors. Like what I see as red, you may see as blue. Ugh.
Definition I’m using is any color that can be expressed as a single wavelength of light. Purple cannot be, since it’s actually two wavelengths simultaneously.
Perceiving it as a color seems more practical though. It’s not like we look at “red” and think “ah yes, a single wavelength of light”