questionsis indigo a color of the rainbow?

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isn't every color represented in the rainbow? it might not be as prominent as the roybgv set but neither is a lot of other colors that people don't argue about.

and don't we have a lot bigger issues to argue about? if not we must live pretty nice lives.

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@moosezilla: it's Red, Orange, Yellow, Green, Blue, Indigo, Violet

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If Orange counts then Indigo counts. Newton started with 5 primary colors and added these two later.

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A color Lesson for you non "colorists"

Primary colors are: Red, Yellow, and Blue
Secondary Colors are a mix of 2 primary colors, Orange, Green, And Volet
Now there is a third group of colors called tertiary colors: Red-Orange, Yellow-Orange, Yellow-Green, Blue-Green, Blue-Violet and Red-Violet.

Blue-Violet might also be called Indigo but why if we're including one tertiary color why aren't we including them all?

Here's the answer, When the visible spectrum was being "Named" there was an obsession with lists of 7 which was purported to be "God's Number" So when they got to Red Orange Yellow Green Blue Violet they thought well lets just throw another one in that's where Indigo comes in. If you're going to include Indigo I feel like you need to throw in all the tertiary colors as well.

Red
Vermilion
Orange
Orange-Yellow (can't figure out a color name for this)
Yellow
Chartreuse
Green
Cyan
Blue
Indigo
Violet
Fuchsia

Or RVOOYCGCBIVF Doesn't that just roll off the tongue?

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Yes, it's the I in the BIV of ROY-G-BIV

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@gideonfrost: Thanks for the clarification. My wife who is a colorist (I assume--she may just be making stuff up) just rolls her eyes at me.
She talks all those colors like vermillion and I have no idea what she's talking about. I tell her I have eight colors in my crayon box-- the six primary and secondary colors you named (except violet, which is clearly just purple with a diploma) plus brown and black.
Anything more than that is just showing off. ;)

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Yes, it is. Pluto is also the 9th planet. YMMV

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THERE IS NO INDIGO. ONLY ZUUL!

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@gideonfrost: I generally call orange-yellow "gold".

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Rainbows are personal. They can be any color you want them to be. I found them to be much more colorful and abundant in college during Dead concerts. Sometimes they danced all by themselves..

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TL;DR: A rainbow has every color so by definition it contains Indigo.
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@gideonfrost:

I hate to throw a monkey wrench into this, but... (actually, to be honest, I love throwing monkey wrenches into things...)

It depends on whether one is talking about a subtractive color system, which starts with light containing all (or most) colors (ie. "white light") and then removes some of those colors with filters or by absorption; or an additive system, which starts with light of specific color(s) and adds them together to make other colors.

With an additive system, the primary colors are normally taken to be Red, Green and Blue. Combinations of these base colors are used to form any (and every) other color, eg. Yellow = Red + Green, Cyan = Blue + Green, Magenta = Red + Blue, and White = Red + Green + Blue. The primary example for most of us is a color CRT screen; another example is HTML Color Codes.

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Perhaps the issue is more of an argument over the definition. There is no color that is inherently "indigo" it is a color that is ascribed to something we see in the range of spectral wavelengths: 381-450nm according to Wolfram Alpha. , so by a quantifiable, scientific point of view... Yes.

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@jsoko:

Your answer has nothing to do with the question.

The question is (see above), "Is indigo a color of the rainbow?"

Let's break it down...

Is Indigo a color? Short answer: yes. (Longer answer: While different people may not be able to agree on the exact wavelength of the color indigo, all people with normally functioning eyes are able to detect light of wavelengths in a continuous region of the electromagnetic spectrum from blue (longer than indigo) through violet (shorter than indigo). Thus, indigo is a color.)

Does a rainbow contain light of wavelengths including the range from blue through violet, and thus including indigo? Short answer: yes. (Longer answer: This one is a bit harder to accept without scientific measurement but if we were to use a prism to break sunlight into its spectrum, we would detect light of the wavelengths called indigo by all people with normally functioning eyes.)

Thus, the rainbow contains the color indigo.

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@baqui63: Clearly you did not read my answer correctly. If you click on the link, you are provided with my source.

As far as the ROY G BIV, as students (at least when I was in school) were taught in elementary school, is concerned, the 'I' for indigo is part of the classification of 'V' for violet currently. So now students are taught ROY G BV, absent is 'I'. So clearly indigo is not considered one of the main colors of a rainbow, as my answer shows.

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@baqui63 broke things down pretty well. It's a single color (a spectral color: light of a specific wavelength can be considered indigo) and thus is in the rainbow.

Only colors that don't recognizably exist as a single wavelength would be considered as "not in the rainbow" in my eyes (no pun intended). The obvious example of that is magenta, which can only be expressed by the combination of red and blue (there is no single wavelength that "is" magenta, you have to have at least 2 separate wavelengths that our eyes add together.

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@jsoko:

I read your source and stand by my answer, and by my assertion that your answer has nothing to do with the question that was asked. :)

Technically speaking, the question is asking whether or not sunlight contains the wavelengths perceived by humans as the color indigo.

Your answer has to do with the number and names of the arbitrary segments into which the visible portion of the electromagnetic spectrum is divided.

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@lordebon:

Hmmm... I'm not sure I agree with your point about magenta.

Given a person who perceives a specific combination of red and blue light as magenta; if that person also perceives a single shorter (likely in the violet region of the spectrum) wavelength of light as the same color, is not the single wavelength also the color magenta?
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Yes, this whole thing is a (somewhat) philisophical monkey wrench, but the whole concept of colors and their perception are also philisophical, no? And in my defense, I clearly stated above my love for throwing these monkey wrenches. :)

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I see brown things flying through the air here. I have to add brown, now.

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@baqui63: I think you are reading too much into the question. Lol. The question was "Is indigo a color of the rainbow?" as you stated earilier and by what my eyes perceived as I originally read the question. This "yes or no" question I answered with a definitive answer of "no" to which I explained and re-explained. If that is not answering the question, I must need a new degree because I am not a lawyer and I intend to answer questions straight forward.

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@baqui63: That would be true if there was some single color that people would see as magenta. But the thing is that there isn't, there is no single color that is magenta. It only exists in the color spectrum in the region between violet and red (which necessarily requires 2 wavelengths).

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@jsoko:

A rainbow is a naturally occuring optical effect formed by water droplets (mist) in the atmosphere separating the sun's light and projecting the result onto other water droplets (coulds) which then reflect the separated light into our eyes. The same effect can be viewed by using a polished block of clear glass with varying thickness (a prism) to separate the sun's light.

These rainbows contain light at the wavelengths percieved by humans as the color indigo.

Based on your answer to the question and your stated reason for that answer, I am guessing that our disagreement stems from your interpretation of rainbow to mean something other than the naturally occuring optical effect described above.

I believe that "my" definition of rainbow is the simpler and more basic one, which is why I feel that it is you who are "reading more into the question."

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Regardless of who is "reading more," would you agree that the above explains the reason for our different answers?

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@lordebon:

Hmmm... after some research, I'll grant that you are correct. Thanks, I learned something.

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@baqui63: I completely agree that the wavelength that indigo is formed by is in the rainbow and I know how rainbows form. My arguement is based the teaching ROY G BV vs ROY G BIV, as the point was made earilier if you teach kids indigo is one of the base colors of a rainbow, why is orange-yellow and cyan left out. Kids can't understand that there are an infinit numbers of colors that are in a rainbow, so you have to limit the amount you teach.

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@jsoko:

WRT teaching kids, & based on their age and ability to understand details, wouldn't it make more sense to teach them that the visible spectrum is currently divided into six regions (ROYGBV) & that it used to be divided into seven regions (ROYGBIV), even though it was originally divided into five regions (RYGBV) & the two extra (OI) were added because in Newton's day, seven was a cooler number than five? One could explain that the normal human eye has three types of color receptors & because of the way they work & interact our eyes are most sensitive to light in the yellow region, which happens to be that emitted most strongly by our sun. One could also mention that some people lack some of these receptors & thus we have people with color-blindness.

I don't teach kids (other than my own daughters and they are mostly on their own at this stage) but if an argument about whether or not I should be part of ROYGBIV is where it's at, I wonder whether we've missed the real point.

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@baqui63: I can't agree with you more! But it's kinda hard to draw a rainbow with infinite colors when you only have an 8 pack of crayons. haha

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No indigo is not a color of the rainbow because not everybody sees it. And Pluto is a dwarf planet

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@daveinsocal: you are correct and what is zuul?