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Question
Aside from Newton's invention of ROY G BIV, does modern science consider violet to be blue or purple?  

Violet used to be considered blue.

Is purple considered magenta?  

This link states that purple is magenta - and they both don't exist:  http://scientificbritain.com/post/44136284657/purple-or-more-accurately-magenta-

So is purple the same as violet?  Is purple the same as magenta? Is violet the same as magenta? If purple is magenta, then it shouldn't have a wavelength because magenta photons don't exist.

Is there a wavelength for violet (if violet is purple)?
Is there a wavelength for purple?

It seems to me that purple and violet photons do not exist if they are purple which is considered magenta according to SCIENTIFIC BRITAIN.

Should we abandon Roy G Biv?  It makes more sense to have Roy G B - no indigo or violet (because indigo is simply darker blue).

Answer
Hello Elizabeth,

It will insert my answers immediately after your individual questions. Please allow me to use all caps so you can easily see what I have said in response. Honest, I am not shouting.

I will talk about spectral colors and the wavelength range for each of the colors. Spectral colors is a name assigned to light that is uniformly a single wavelength. Society has given individual names to spectral colors that seem different from other colors (giving rise to RoyGBiv). The following links will take you to sites that discuss those terms.
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/specol.html
Note: This site omits assigning the term Indigo to any location in the spectrum. I don't know why they did this. I normally agree with the way hyperphysics discusses Physics. And they included Cyan.
http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Spectrpy/UV-Vis/spectrum
Note: This site gives wavelength range for each of the colors. Other sites will have slightly different dividing wavelength numbers dividing adjacent colors. The colors change so gradually throughout the spectrum that it is very subjective.

Aside from Newton's invention of ROY G BIV, does modern science consider violet to be blue or purple?  MODERN SCIENCE CONSIDERS VIOLET TO BE ONE OF THE NAMED SPECTRAL COLORS. IT IS THE NAME GIVEN TO LIGHT THAT HAS A WAVELENGTH IN THE RANGE OF 400-420 nm. SO VIOLET IS VIOLET. IT IS SIMILAR TO BLUE IN THE WAY THAT ORANGE IS SIMILAR TO YELLOW.

Violet used to be considered blue. WELL, YES PERHAPS. ORANGE COULD BE ARGUED TO BE JUST PART OF THE TRANSITION FROM RED TO YELLOW.

Is purple considered magenta? THERE SEEMS TO BE VARIOUS OPINIONS ON THAT. SEE THESE SITES:
http://desktoppub.about.com/cs/colorselection/p/purple.htm
https://simple.wikipedia.org/wiki/Magenta
https://www.sitepoint.com/color-in-design-purple/

This link states that purple is magenta - and they both don't exist:  http://scientificbritain.com/post/44136284657/purple-or-more-accurately-magenta-
STATING THAT PURPLE OR MAGENTA IS NOT A COLOR SEEMS TO BE A MATTER OF TERMINOLOGY. I THINK THE SCIENTIFICBRITAIN POST IS DEFINING "COLOUR" IN THE WAY THAT HYPERPHYSICS DEFINES "SPECTRAL COLORS" (the color of light that is uniformly a single wavelength). IT IS TRUE THAT THERE IS NO WAVELENGTH OF ELECTROMAGMETIC RADIATION THAT PRODUCES THE COLOR PURPLE. IT REQUIRES MIXING SPECTRAL COLORS AND LETTING OUR MIND INTERPRET WHAT IT MEANS WHEN THE RED AND BLUE CONES BOTH FIRE. SO I WOULD HAPPILY AGREE WITH SCIENTIFICBRITAIN IF IT SAID "purple is not a spectral colour, it must be created by mixing spectral colours".

So is purple the same as violet? NOT IF WE ARE TALKING ABOUT THE SPECTRAL COLOR VIOLET. BECAUSE PURPLE IS NOT A SPECTRAL COLOR. NOTICE THAT THE desktoppub SITE INCLUDES VIOLET AS A SHADE OF PURPLE. THEY SAY THAT NOT AS SCIENTISTS, BUT (APPARENTLY) AS ARTISTS.
Is purple the same as magenta? THE WIKIPEDIA SITE SAYS THAT MAGENTA IS A COLOR BETWEEN RED AND PURPLE OR PINK AND PURPLE. SO NOT QUITE THE SAME - SIMILAR.
Is violet the same as magenta? INSERT VERY SIMILAR ANSWER AS FOR YOUR PURPLE/VIOLET QUESTION ABOVE.
If purple is magenta, then it shouldn't have a wavelength because magenta photons don't exist.
TRUE.

Is there a wavelength for violet
YES
(if violet is purple)?
BUT IT IS NOT - ARTISTICALLY PERHAPS, BUT NOT SCIENTIFICALLY.
Is there a wavelength for purple?
NO.

It seems to me that purple and violet photons do not exist
AGREE FOR PURPLE, DISAGREE FOR VIOLET.
if they are purple which is considered magenta according to SCIENTIFIC BRITAIN.

Should we abandon Roy G Biv? It makes more sense to have Roy G B - no indigo or violet (because indigo is simply darker blue).
I THINK VIOLET HAS TO STAY. JUST OUTSIDE THE VISIBLE SPECTRUM FROM WHAT WE CALL VIOLET IS ULTR-VIOLET. WOULDN'T MAKE MUCH SENSE TO HAVE ULTRA-VIOLET WITHOUT A VIOLET ADJACENT TO IT. REMEMBER THAT HYPERPHYSICS DECIDED TO LEAVE INDIGO OUT OF THEIR SPECTRUM. BUT THEN INCLUDED CYAN. CYAN IS IMPORTANT IN PRINTING. SO PERPHAPS Roy G C B V. WOULD YOU CONSIDER OMITTING ORANGE? IT IS JUST THE TRANSITION BETWEEN RED AND YELLOW. SO RYGCBV. BUT I REMEMBER LEARNING Roy G Biv FROM ALMOST 60 YEARS AGO. I WOULD NOT EASILY REMEMBER RYGCBV. SO I WILL STICK WITH Roy G Biv.

REGARDING THE BLUE/INDIGO/VIOLET PART OF THE SPECTRUM. WHAT HAPPENS WITH THE CONES WHEN TRYING TO DIFFERENTIATE BETWEEN THOSE COLORS? COMPARED TO THE CONES' RESPONSE TO BLUE, HOW ARE THE RESPONSES FROM THE CONES, WHEN THE COLOR IS VIOLET, DIFFERENT? I SUSPECT THE GREEN CONE PUTS OUT A LOW AMPLITUDE MESSAGE TO THE BRAIN WHEN THE COLOR IS BLUE. AND I SUSPECT THE GREEN CONE'S OUTPUT DECREASES GRADUALLY AS THE EYE SCANS ALONG THE COLOR CHART TOWARD VIOLET. I HAVE NOT STUDIED THIS, BUT IT SEEMS LIKELY TO ME. YES, THE DIFFERENCES IN THE BLUE/INDIGO/VIOLET PART OF THE SPECTRUM MAY SEEM MORE SUBTLE THAN FOR RED/ORANGE/YELLOW BUT I WOULD DISAGREE WITH A SUGGESTION TO JUST CALL IT ALL BLUE.

I hope this helps,
Steve

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Steve Johnson

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I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

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I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

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BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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