What is the wavelength of pure violet?

[zyxwv99]

What is the wavelength of pure violet?

 

[oahu99]

405nm?
I guess it depends on your definition of "pure violet"

 

[Encap]

Colors that can be produced by visible light of a narrow band of wavelengths (monochromatic light) are called pure spectral colors. The spectrum is continuous, with no clear boundaries between one color and the next.

The various approximate color ranges are:
violet 380–450 nm, blue 450–495 nm, green 495–570 nm, yellow 570–590 nm, orange 590–620 nm, red 620–750 nm

See: Visible spectrum - Wikipedia, the free encyclopedia
and
http://en.wikipedia.org/wiki/Violet_(color)

 

[Lotus_Darkrose]

Why are these being created as polls?

 

[zyxwv99]

Why are these being created as polls?

Because otherwise I get a lot of explanations that don't answer the question but merely repeat introductory concepts. I like explanations based on actual observations, as in "I saw this kind of laser, and here's what it looked like."

The problem with more general explanations is that I'm already familiar with most of them. For example, brightness can affect how we perceive hue (that's the Bezold–Brücke shift). Lightness and desaturation can have a big effect too (Abney effect).

Then there are cultural variables. Isaac Newton's "blue" is what people today would call "sky blue" -- his "indigo" is today's "blue" or "sapphire blue." The dividing line between blue and green that most Americans today are familiar with is pretty much the same in other English-speaking countries, as well as other countries where Germanic and Romance languages are spoken, but hardly anywhere else in the world.

I've already studied dozens of items like this. For violet, issues include eye fluorescence, which can affect vision even in the 500s, and kicks in with a vengeance below 420 nm, or the fact that below 395 nm (±5 nm) color trends towards desaturated blue.

What I'm looking for is wavelength numbers from people who have access to things like lasers, monochrometers, digital spectrometers. Numbers that are not among the options are perfectly welcome. For example, my poll on "orange" suggests that 604 nm is a better choice than 605 nm. (In some parts of the spectrum, such as high 600s, ten or twenty nm makes little difference, but in some places even a few nanometers matter.)

 

[crazyspaz]

Why are these being created as polls?

I wish I knew.

 

[trencheel303]

Because otherwise I get a lot of explanations that don't answer the question but merely repeat introductory concepts. I like explanations based on actual observations, as in "I saw this kind of laser, and here's what it looked like."

The problem with more general explanations is that I'm already familiar with most of them. For example, brightness can affect how we perceive hue (that's the Bezold–Brücke shift). Lightness and desaturation can have a big effect too (Abney effect).

Then there are cultural variables. Isaac Newton's "blue" is what people today would call "sky blue" -- his "indigo" is today's "blue" or "sapphire blue." The dividing line between blue and green that most Americans today are familiar with is pretty much the same in other English-speaking countries, as well as other countries where Germanic and Romance languages are spoken, but hardly anywhere else in the world.

I've already studied dozens of items like this. For violet, issues include eye fluorescence, which can affect vision even in the 500s, and kicks in with a vengeance below 420 nm, or the fact that below 395 nm (±5 nm) color trends towards desaturated blue.

What I'm looking for is wavelength numbers from people who have access to things like lasers, monochrometers, digital spectrometers. Numbers that are not among the options are perfectly welcome. For example, my poll on "orange" suggests that 604 nm is a better choice than 605 nm. (In some parts of the spectrum, such as high 600s, ten or twenty nm makes little difference, but in some places even a few nanometers matter.)

None of that changes the fact that the question you're asking is purely speculative. The only thing less pure than pure violet is violet mixed in with some other colour. My eyes sometimes see 405nm as a grey beam - it's still "pure" violet though.

My eyes also see virtually no difference between 635 and 650, the camera sometimes sees more of a difference and some around here say they can see quite a difference.

 

[Jmillerdoc]

Why are these being created as polls?

My gosh man, are you serious! Just try to imagine the world without them! Unbearable, totally unbearable.....

 

[Encap]

Because otherwise I get a lot of explanations that don't answer the question but merely repeat introductory concepts. I like explanations based on actual observations, as in "I saw this kind of laser, and here's what it looked like."
For example, my poll on "orange" suggests that 604 nm is a better choice than 605 nm. (In some parts of the spectrum, such as high 600s, ten or twenty nm makes little difference, but in some places even a few nanometers matter.)

What question? What is it you want to know/determine?
From what you say there is no specific absolute wavelength answer to your question. There is no better choice or worse choice.

As I mentioned in prior post The electromagnetic spectrum wavelength range is continuous, with no clear boundaries between one color and the next . There are words for segments of the wavelength range.

A color is whatever anyone says it is based upon their experience of wavelengths and their physiology at a given time under given circumstances--perception of colors is an internal human event not an external thing. No two people share exactly the same perception of anything including color, any more than they share their individual birth or death, even if both are viewing the same thing at the same time.

Sounds like you are looking for a absolute wavelength for a "word" whose definition is a range--there is no such thing.

Eye sensitivity to wavelength and perception of color under whatever conditions is a subjective, a characteristic of the individual not of a word for a color nor a wavelength. Everyone sees colors differently, no two individual have exactly the same perception. Violet or any other color word is what a majority of people agree it is---thus thus word symbol for a range of wavelengths which is the definition of -- a color.

 

[zyxwv99]

None of that changes the fact that the question you're asking is purely speculative. The only thing less pure than pure violet is violet mixed in with some other colour. My eyes sometimes see 405nm as a grey beam - it's still "pure" violet though.

My eyes also see virtually no difference between 635 and 650, the camera sometimes sees more of a difference and some around here say they can see quite a difference.

Most people can't distinguish different hues of red unless seen side by side. Everything from 635 to 1064 looks red. Yes, people have seen 1064 in vision studies, and described the color as red (Sliney 1976). In other parts of the spectrum it doesn't work that way.

Before I got here, others had done similar surveys on other colors, and got surprisingly consistent results. The results I got for orange were very consistent. However, I was expecting a high degree of variability for violet because of yellowing of the lens and cornea with age and lifetime exposure to uv, as well several other issues. Thus, variability was the main thing I was looking for.

The science of color naming is not speculative, but is an important subfield of linguistics as well as an interdisciplinary field in its own right. For example, linguists have surveyed people in hundreds of traditional societies (including "primitive tribes") to find out how many words they have for subjectively primary colors, and what those names refer to. What they found is consistent patterns across cultures. For example, in languages with only three color words, the three words almost always refer to light, dark, and red. In those with four, five, or six color words, they tend to refer to the same patches of the spectrum as in other cultures and languages.

Several years ago, TAPPI (the paper industry association for the US and Canada) commissioned a study on white paper. They showed 25 people custom-made sheets of paper tinted very faintly in red, green, and brown. An organization called CIE sets international standards for light and color (they were the ones that defined the lumen, an SI unit), and among others things have a widely-used definition of "white." However, the TAPPI study confirmed what paper manufacturers had long suspected: that CIE's definition of "white" includes many tints that most people would call pink, green, or beige.

Meanwhile, the paint industry has given up on color names and just relies on digital spectrometers to match paint. Others don't have that luxury. Safety engineers, for example, or graphic designers involved in product packaging. Also, traffic engineers, people who set the standards for indicator lights, navigation lights, warning signs, the list goes on. In many cases, the name assigned to the color really matters.

And finally, I have a nephew who's very short. At one point, his parents were considering hormone injections to make him taller. Fortunately, the medical profession has done polls on this, finding out how tall or short someone would have to be in order to be considered "tall" or "short." Even though the results can vary by country and socioeconomic status, the results inform important medical decisions that can affect someone's quality of life.

 

[Polonium210]

This question makes no sense :thinking:

Everyone's perception of the color spectrum is different.

Like Encap said:

"The spectrum is continuous, with no clear boundaries between one color and the next."

What defines a "true color" is its specific wavelength.

 

[zyxwv99]

This question makes no sense :thinking:

Everyone's perception of the color spectrum is different.

Like Encap said:


What defines a "true color" is its specific wavelength.

Everyone knows that the spectrum is continuous.

Of course everyone's perception of the color spectrum is different, but how different? Vision studies have found that the color of ultraviolet trends towards desaturated blue below 395 nm (±5). That ±5 is a crucial bit of information.

At the opposite end of the spectrum things are more definite. The most pure hue of red is perceived at 704 nm. At that wavelength, the R/G ratio is 15. That's the ratio of red-cone to green-cone stimulation. Below 704 nm, light looks more orange as the R/G ratio declines. Above 704 nm light looks more orange as well, as above that point the sensitivity of green cones declines more slowly than that of the red cones. At 800 nm the R/G ratio is 12, the same as at 663 nm.

You say: What defines a "true color" is its specific wavelength.

I never used the word "true." I said "pure." The wavelength by itself does nothing. Color is perceived when light of whatever wavelengths impinges on the eye and then gets processed by neurons. There's a whole science devoted to that. However, I am also concerned here with the next step: what word we give the color. That's linguistics, and it's related to culture.

 

[DrSid]

For me, no single wavelength is violet .. I need red mixed in ..

 

[Jmillerdoc]

I am honestly curious what you will do with this polling data?????

 

[sinner]

The question is "how violet are you?" turns out Im 80% violet. jokes apart,
I think this is a valid question but then again ultraviolet is also violet(?) So I think 405nm is the most common analogy for violet wavelength.

 

[zyxwv99]

I am honestly curious what you will do with this polling data?

Laser colors is one of my hobby interests. I am also interested in the history of weights and measures, especially British/English/American, going back to the Middle Ages, and have edited numerous Wikipedia articles on the subject. For me, the most fun part is the research and solving mysteries. I'm also interested in diamonds (even though I can't afford any that cost more than $50). Plus history of Thanksgiving, Guy Fawkes Day, and betrothal rings in early colonial America.

To see what I have done on this subject so far, take a look at my photo album. I just uploaded the latest version. Before polling, I had a hunch that 460nm was the sweet spot for blue, 605nm for orange, but I never expected so many people to agree with me. (Except it looks like orange is actually 604, since 1 nm actually makes a difference in that part of the spectrum.)

I just assumed that everyone would say 420 and below is violet (which it still shows on the chart I made) but apparently not. I haven't gotten one vote for anything higher than 405.

Also, knowledge is power. I am an unemployed graphic designer, and this sort of knowledge can prevent huge disasters, as in having to reprint something because the customer didn't like the way the color turned out. But basically this is just science-geek hobby.