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The Difference Between ‘Violet’ and ‘Purple’ (2015)
- bregma 8y agoWhat about aubergine?
- dreen 8y agoInteresting article "So, purple is more reddish and saturated, while violet is more bluish and less saturated." I'm slightly colorblind and this sentence made me WTF out loud. Purple in that picture looks way more bluish than violet. "If you take a look at the distance between violet and blue in the picture of the spectrum above, it is about the same as the distance between green and orange." Since I can easily mistake the colours in any of such pairs I assume that colorblindness works by "muddying the lines" of spectral representation of colour? Would that make it a neurological problem rather than an optical one?
- wycy 8y agoMy understanding of color blindness has always been that it's typically a problem with the actual eye cones for color sensing--at least for non-pathological cases of color blindness.
- OscarCunningham 8y agoI used GIMP to maximally saturate the colours: https://i.imgur.com/wfyEWcP.png https://i.imgur.com/wfyEWcP.png Does the purple still look more blue than the violet?
- dreen 8y agoHmmm, no I guess not. If I didn't know I'd just label both as blue.
- jerf 8y agoAs others are pointing out, it's worth remembering our monitors aren't necessarily even capable of producing true violet. And I'd add that monitors vary widely in quality themselves. This one I'm typing on doesn't yell to me "piece of crap", because I mostly do coding-type activities on it and it's plenty fine to do syntax highlighting, but sometimes when the rotating desktop background shows the same one on this monitor and the built-in Macbook monitor, it's like, huh, there's a lot of difference there. It really wouldn't be a great monitor to watch media on routinely. We aren't even all looking at the same colors in the first place.
- dreen 8y agoYeah I get the same impression, it's just that I don't think I could recognise those as Purple and Violet even in non-oversaturated form, to me it's all just different nameless hues of blue.
- qubitcoder 8y agoI'm not so sure about that. The left side appears _overwhelmingly_ purple, and the right side looks _very_ blue. Have you tried something like the Farnsworth-Munsell 100 hue test?
- dreen 8y agoThanks, that was an interesting test. I guess my feeling of "I'm slightly colourblind" is correct. I don't seem to have that many problems with blue though. My results: https://imgur.com/a/0AvU4hX https://imgur.com/a/0AvU4hX
- mcv 8y agoDoes anyone know what colourblindness really is? My guess would be that it's one (or more) of the cones either not working properly, or working differently, creating a very different colour experience. For example, looking at the graph in the article, I'd expect that if your green cones don't work, you'd see no real difference between green and red. If your blue cones don't work, blue would look slightly red. If red cones don't work, again red and green are roughly the same, but violet would look blue. But that's entirely my uneducated guess as a complete layman on the subject. As for the purple and violet in the picture, that violet can never be true violet because it mixed by your computer screen from RGB colours, so it's really created by mixing more blue with red, and probably a bit more green, since it's a lighter colour (adding more of the least represented colour moves it closer to white I think). So if that looks more red to you than the equally mixed purple, the only explanation I can think of is that it might come from the added green, which your eyes might register as potentially red if it's your red cones that don't work properly. But again, pure guesswork on my part.
- frosted-flakes 8y agoWe know exactly how colour blindness works. Usually, the cones all work, but the range of wavelengths they can detect is slightly shifted from normal. Red-green/green-red colour blindness is the most common, and in that case the range of wavelengths that the red and green cones can detect overlaps more than they usually do. That's how I understand it anyway.
- jobigoud 8y agoAnd that's how we are all colorblind compared to tetrachromats. They have four cone types that don't overlap. I wish in the future there will be a procedure where you can have cone cells injected to unlock these new colors.
- mcv 8y agoWould we be able to interpret those colours? How will our brain handle and interpret them? It might be like having to learn to see all over again. It's certainly a cool idea, though. And you don't have to stop at four. Don't butterflies have 6 different cones or something?
- hawski 8y agoViolet in the article is not a real violet. A computer screen shows violet as a mix of red, green and blue as all colors. So the violet in the article is really a blueish purple. Also many file formats encode them as such. That's only an approximation.
- waynecochran 8y agoColor blind / dichromat here: They're pretty much all shades of blue to me.
- myself248 8y agoThis may also explain why digital cameras have such trouble picking up certain purple/violet colors but not others.
- jacobush 8y agoYou mean the hump in the red detectors of the human eye? I had no idea about this!
- jobigoud 8y agoThere is no hump in the red detectors. The hump exists only in curves we use to translate light into RGB, and is there precisely to help translate that violet into purple. https://en.wikipedia.org/wiki/Cone_cell https://en.wikipedia.org/wiki/Cone_cell
- tgb 8y agoThanks for pointing this out, thought I was going crazy. So the article's explanation of why violet and purple look similar even though they are completely unrelated in spectrum is bogus (the article claims it's due to this secondary peak in the red cone). So what's the real reason?
- pygy_ 8y agoQuoting the legend of said picture in the article: """Note that this chart does not show the spectral properties of the cones themselves (but they look similar). It represents the CIE 1931 colour space, which, simply put, corresponds to the signals after they have been processed by the brain."""
- tgb 8y agoQuoting the last section of the article: """The reason why purple and violet look similar to us is because they stimulate our cones in a similar way, but most other animals don’t share the same types of cones and “post-processing”. This means that to other animals, purple and violet may look completely different!""" Emphasis theirs. This is the part I'm calling out. Stimulation of the cones is not relevant! (Of course the cones are relevant but the difference is very much larger and of a different nature than they make it out to be. Most mammals have only two color cones.)
- mcv 8y agoFascinating. I've often thought about how purple relates to violet, but never really figured it out. There are of course colours we call violet that we make by mixing red and blue. For example, the colours in this very article, which use RGB colours to mix red, green and blue light to create violet. So the violet in this article isn't "true" violet at all; it's just a faded bluish purple. So are there real world paints that are actually violet? Or is the violet from the rainbow something we cannot truly reproduce, and only fake by mixing red and blue?
- deleted 8y ago[deleted]
- OscarCunningham 8y agoWhite light contains light of all frequencies, so a violet paint that only reflected a single frequency would look very dark since it would only be reflecting a tiny proportion of the light that hit it. Even if it reflected a range of frequencies around violet it would still look very dark unless the range was large enough to also contain a lot of blue. If you wanted to see "true" violet, your best bet would be to find a monochromatic violet light source. A Blu-ray laser would do the trick. But it won't look any different from the RGB imitation aside from being brighter. EDIT: Please do not shine a Blu-ray laser directly into your eye.
- creatornator 8y agoIf your white light source has a flat spectrum, then the violet paint wouldn't be any dimmer than any other color. The reason red or blue paint looks bright enough to see is because, as you said, they do reflect a range. So the violet paint could reflect the same bandwidth range as the traditional visible spectrum paints, and it would have the same power density. Unless you mean appearance, in which case, yeah, our eyes don't detect violet very well.
- rootusrootus 8y agoHow about a blacklight? The frequency of light you can see leaking through the filter is 404nm, so that should be a relatively safe way to see what "spectral violet" looks like, right?
- jobigoud 8y agoThis has long been a pet peeve of mine. I don't disagree with it but the colors shown in the article aren't violet, they are all shades of purple. Spectral violet is outside the gamut of most RGB color spaces, including sRGB, Adobe RGB, Pantone, CIELAB, etc. Monitors also wouldn't be able to reproduce it anyway. The CIE 1931 curve showing a bump in red inside the blue is misleading I think. It does not represent how the cones react (the article says so in small print). The L cones aren't excited at all when pure blue or indigo or violet light hits them. The graph was built to find the best RGB primaries to use in order to best "emulate" how we interpret colors, so I think it actually already encodes our bias and general lack of skill at distinguishing violet from purple. Similarly many people don't really make a distinction for cyan and just call it blue or green when they see it.
- NikolaNovak 8y agoWhat would be the best way to get the true spectral violet then - a paint chip from hardware store? Also, do you by any chance have a handy link to an actual graph on how cones react to various spectra of light? Many thanks!
- tgb 8y agoA prism, probably.
- ddeck 8y ago>do you by any chance have a handy link to an actual graph on how cones react to various spectra of light? I think you'll find everything you need here: http://www.handprint.com/HP/WCL/color1.html http://www.handprint.com/HP/WCL/color1.html and elsewhere on the same fantastically web 1.0 style site[1]. Bruce Macevoy is an artist with penchant for color theory. [1] https://www.handprint.com/HP/WCL/wcolor.html https://www.handprint.com/HP/WCL/wcolor.html
- reitanqild 8y ago> elsewhere on the same fantastically web 1.0 style site[1]. Refreshing! I want to read that site even if I don't care too much about colours. (The only thing I kind of miss is if it could be even easier to read on mobile.)
- thraway-burnout 8y agoIs this article using Violet to refer to Indigo?
- jobigoud 8y agoPeople use words differently. Indigo is somewhere below blue in the spectrum, and violet is below indigo. Some people call a mix of red and blue "violet" but they should use the word purple instead. The French word "pourpre" is often used as a translation for purple, but actually refers to a color with more deep red mixed in.
- mannykannot 8y agoOf the seven traditional named spectral colors, indigo and violet seem to be the least distinct pair. Newton may have included it mainly to have seven named colors, as a parallel to the seven notes of the western major scale in music. He admitted that his ability to distinguish colors was not acute, and, after he had selected his seven, he asked others to mark them off on a spectrum projected on a wall. This is different, of course, then asking them how many distinct colors they thought best characterized the visible spectrum. https://en.wikipedia.org/wiki/Indigo#Classification_as_a_spectral_color https://en.wikipedia.org/wiki/Indigo#Classification_as_a_spe...
- OscarCunningham 8y agoWhat I've heard as the explanation is that his "blue" referred to our "cyan" and his "indigo" referred to our "blue".
- aasasd 8y agoWhich almost exactly corresponds to the ‘rainbow colors’ as used in Russian (and probably other Cyrillic languages). The color swatches in the linked article are precisely Russian ‘blue’ for Newton's indigo and ‘lightblue’ for blue.
- pdpi 8y agoViolet is the bit of the visible spectrum just shy of ultraviolet (by definition, really).
- raverbashing 8y agoSo, do colorblind people see Violet and Purple "more differently" than non-colorblind then?
- mcv 8y agoI'd expect so. It's simultaneously easy and hard to test. Easy because you need to show something violet on a similar purple background, and hard because we're not good at producing violet: computer screens and regular printers won't work.
- mongol 8y agoIt is interesting to me that if there would be a way to stimulate red and blue cones, without stimulating green, you would see a color never seen before. As there is no wavelength that accomplishes that.
- floatrock 8y agohttps://en.wikipedia.org/wiki/Tetrachromacy https://en.wikipedia.org/wiki/Tetrachromacy You've heard of super-tasters? There's a genetic variation that creates a kind of fourth color receptor in some people, apparently giving them the ability to perceive colors others can't! > One study suggested that 2–3% of the world's women might have the type of fourth cone whose sensitivity peak is between the standard red and green cones, giving, theoretically, a significant increase in color differentiation.
- tambourine_man 8y agoColour Mixing: The Mystery of Magenta The Royal Institution https://www.youtube.com/watch?v=iPPYGJjKVco https://www.youtube.com/watch?v=iPPYGJjKVco
- isoskeles 8y agoTo me, most of these discussions about color come off as, “Weird flex but okay.” And I don’t care if you know how the human eye perceives color. There is a distinct difference between how we talk about color and how we perceive it, and while it’s helpful to understand both (especially if you need to for your profession), I don’t find it helpful to act like you’re smart for knowing this. Or similarly, to act like other people are stupid and it’s a “pet peeve” of yours that they use the word “violet” to describe a color instead of spectral light. Words can have multiple meanings, and the violet ship has sailed.
- ineedasername 8y agoI'm surprised this doesn't mention the Sapir-Whorf hypothesis and the work done by Paul Kay & Willett Kemptom to test this with color labels. Basically it found that the presence of labels on colors influenced the decisions speakers of different languages, with different lexical entries for colors, made when categorizing colors in the presence of labels. However, absent labels, the decisions made became more "absolute" with respect to the color spectrum and less subjective, and different language speakers' decisions began to match each other. [0] [0] http://www.blutner.de/color/Sapir-Whorf.pdf http://www.blutner.de/color/Sapir-Whorf.pdf
- deleted 8y ago[deleted]
- ohduran 8y agoGood one, but the part where we as a society collectively define what 'violet' and 'purple' means is lacking. It's all been covered in a wonderful book called Through the Language Glass, by Guy Deutsch. Find my notes on that book on https://alvaroduran.me/through-the-language-glass https://alvaroduran.me/through-the-language-glass Edit: fix link
- bprasanna 8y agoWell the same kind of confusion exist in color books for toddlers. In most books they show purple color for violet. Or they call violet as purple! https://curiosity.com/topics/violet-and-purple-arent-the-same-thing-curiosity/ https://curiosity.com/topics/violet-and-purple-arent-the-sam...
- combatentropy 8y ago> Purple objects are "red and blue at the same time," whereas violet objects are . . . just violet. Not on RGB screens. If I take a color picker to the page's image of a color spectrum, said to contain pure violet, it is still a mix of red and blue. I admit that it is odd that the left end of the spectrum seems to have color from the right end. It's as if the spectrum wraps around, in our mind's eye at least.
- pjungwir 8y agoVery interesting! All my life I've wondered why sometimes we say "violet" and sometimes "purple", with a vague sense that they are not exactly synonyms. Here is a related question that got a very knowledgeable and helpful answer: https://news.ycombinator.com/item?id=17507968 https://news.ycombinator.com/item?id=17507968 (Why is there a color "wheel" when frequencies are linear?) HN is amazing!
- JKCalhoun 8y agoHad an art teacher tell me that "purple" was not a "color" but rather the name of a dye used hundreds of years ago. She said "violet" is the name of that "color" you are referring to as purple.