Quite sure the Geeks here already knew this and I was aware of some of it, but not the details and the Why.
Explains why we all see various LED tints different as well.
Anyway good read;
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Put a blue filter then a red filter on a photo, I wonder what will happen…
To be more precise, some shades of purple don’t exist as monochromatic light. However, some shades of purple definitely do exist as monochromatic light - specifically violet. Other shades only exist as mixed light, but it’s a semantic game to claim that the perceived color of the mixed light doesn’t exist simply because it isn’t a replication of a monochromatic light.
The L-opsin photoreceptive protein in the red-sensitive cone cells in our eyes actually have a bump in their spectral response at the blue end of the spectrum, in addition to their primary function of being sensitive to red. I’ve seen some spectral sensitivity graphs include this, and some trim it out (presumably to allow for a simpler equation to approximate the sensitivity). This example includes the bump:
So if the eye receives light down in the violet range, it not only triggers the blue-sensitive cone cells, but also slightly the red-sensitive cone cells, resulting in a distinctly perceived color from blue. And since mixing red and blue also triggers both the blue and red sensitive cone cells, despite being physically-different wavelengths, we perceive that as similar.
So in my mind, for most purposes this shouldn’t be treated as more complex than recognizing the fact that two different scenarios cause a similar response. Our eye is affected by red + blue light in a similar way as it is affected by violet light. That’s not really that much different to me than the fact that our eye is affected by green + blue light in a similar way as it is affected by cyan light.
Digging deeper, adding enough red into the spectrum triggers our red sensitive cones in greater proportion to the blue cells than is possible with violet light alone. This makes it possible to perceive shades of purple that won’t be perceived from violet light alone, so I’m not going to just dismiss the article as complete nonsense, but I don’t find their characterization that “therefore, purple doesn’t exist” very useful, because there is real overlap between the range of mixed light perceived as purple, and the monochromatic violet light is perceived as a narrower range of purple.
If you study physics, vision, or illumination at a deep level, it can be useful to understand these details. For the average person, however, using these details to arrive at a conclusion like asserting that purple doesn’t exist is likely to cause more confusion than clarity…I know it did for me earlier in my process of learning about color.
By the way, XKCD has also delved into the topic color, the complexities of explaining it, and the fact that at some levels, it is best to keep it simple:
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Purple exists even if we aren’t around to observe it, is the short answer. Just because we may not physically be able to see it doesn’t mean it doesn’t exist…
You go Sheldon!
Real question then is…What color Is the Dress to you?
Sounds about right.
Birds aren’t real, either.
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The bird crap on my side window right now is real!
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I would even say it the other way around: We see purple - and I mean “really” see it, not like it is some sort of hallucination - even if we could also say that some shades of purple don’t exist as monochromatic light.
So if our seeing purple is a real effect, then is it actually useful to say purple isn’t real?
By the way, I accidentally submitted my post when I had only started composing it, and was actually in the middle of rephrasing the part I had written so far. What you responded to was likely not a very complete, and possibly not a very coherent train of thought.
My post is now longer and hopefully makes more sense than it did when you wrote your response to it. And it also now references a semi-relevant XKCD comic!
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Whatever color the dress is, I would not call it purple.
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It’s only an illusion…
I see purple.
Just say the word “purple” it feels good, sounds good and looks good.
Purple is real!
I feel funny.
But I don’t know why.
Like most clickbait titles, it’s not accurate.
Purple is real. Even if we use the definition that violet is an individual wavelength of light and purple is a combination of multiple wavelengths, purple is still real. The clickbait title just uses a peculiar and intentionally misleading definition of “real”.
Saying violet is real but purple isn’t… is like saying the note of “C” is real but the “C major” chord isn’t. Because a chord is more than one note. The combination of notes creates a more complex waveform, so instead of a simple sine wave, it’s a more interesting pattern.
Purple is the same thing, but for light. Instead of being a single “note”, it’s a 2-note “chord”. Instead of a wavelength, it has a wave pattern.
But by the article’s definition, only individual sine waves are “real”. Everything with a more complex wave shape is apparently not “real”. And anything made from more than one “real” sine wave is, apparently, also not “real”.
So… I find it to be an awfully strange definition of the word.
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violet is not purple
The sentence or the whole article is nonsense to some people who consider purple and violet as the same thing in their language and cultural backgrounds.
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Prince Purple Rain.
C Chords for everyone!
Tuning:E A D G B E
Key:Bb
Capo:3rd fret
`(capo on 3rd fret)
Chords:
G 320033
Em 022000
D xx0232
C x32010
[Intro]
G Em D C
[Verse 1]
G Em
I never meant to cause you any sorrow
D C
I never meant to cause you any pain
G Em
I only want one time to see you laughing
D G N.C.
I only want to see you laughing in the purple rain
[Chorus]
C
Purple rain, purple rain
G Em
Purple rain, purple rain
D
Purple rain, purple rain
G N.C.
I only want to see you bathing in the Purple Rain
[Verse 2]
G Em
I never wanted to be your weekend lover
D C
I only wanted to be some kind of friend
G Em
Baby I could never steal you from another
D G N.C.
It’s such a shame our friendship had to end
[Chorus]
C
Purple rain, purple rain
G Em
Purple rain, purple rain
D
Purple rain, purple rain
G N.C.
I only want to see you underneath the purple rain
[Verse 3]
G Em
Honey I know I know I know times are changin’
D C
It’s time we all reach out for somethin’ new
That means you too
G
You say you want a leader
Em
But you can’t seem to make up your mind
D
I think you better close it
G N.C.
and let me guide you to the purple rain
[Chorus]
C
Purple rain, purple rain
G
Purple rain, purple rain (Whew)
if you know what I’m singin’ about
Em
help me and come on raise your hand
D
Purple rain, purple rain
I only want to see you, only want to see you
G N.C.
In the purple rain
[Outro]
G Em D C`
That cat can ball…
Take the pebble out of my hand. Grasshopper.
Jimmy was right. Purple haze all in my brain.
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