The generalization of this is the Planckian locus:
That's the image of the temperature range (0,∞), mapped to the corresponding blackbody color in chromaticity space. The limit T -> ∞ is a point discontinuity near the center of CIE space.
FWIW, that article's top graphic is currently malformed. Hmm, and the text incorrect.
Wikipedia's coverage of this topic has regrettably been unstable over the years. Broken chromaticity diagrams are so common, each time the graphic is swapped, it's a toss up whether it's a correct one. And then edits reflect that, and common misconceptions. Perhaps if WP had not just Article and conversational Talk pages, but also something like a writer's notebook, it might serve as memory, as immune system, as a place to caution "make sure when editing that you don't ...". Perhaps it will stabilize some day - the Sun page seems to have at long last settled on a white-not-yellow Sun. Yay. That's more than several of the most used intro astronomy college textbooks have managed. Science education content is... something we struggle to do well.
 https://en.wikipedia.org/wiki/File:PlanckianLocus.png https://commons.wikimedia.org/wiki/File:PlanckianLocus.png (13:38, 3 January 2012)  Obvious errors: the blackbody curve shown doesn't go through white, and does go through yellow. Incorrect white-point math is a recurring cause.  "It goes from deep red at low temperatures through orange, yellowish white, white, and finally bluish white at very high temperatures." (emphasis added)  https://en.wikipedia.org/wiki/Sun
After twenty years of using wikipedia, my conclusion is this: in order to keep a single article in decent shape, you need both:
1) Constant vigilance, to monitor the article and revert drive-by edits putting up random nonsense.
2) Solid political backup from other long-time wikipedia editors, to fight off constant AFDs and DRN attempts to destroy whatever you've done.
If at any point you slack off, the article will be gutted and replaced with garbage. This resembles any other human endeavor, in that you're valiantly resisting entropy while everyone in the world calls you a moron for even bothering.
As a disclaimer, I suppose I don't see any way this could be technically "fixed", short of replacing humanity with something else.
When I edit an article, it is automatically added to my watchlist, which currently has about 800 articles in it (most of which I don't care about; I should do some weeding). On an average day, maybe 20 of those articles are edited.
Most of those edits are minor. Most vandalism has already been reverted before I see it. A substantial wrong edit needs my attention maybe once a week.
When you speak of "valiantly resisting entropy", it sounds like a battle against the forces of Mordor. For me it's more like weeding the garden; a fairly pleasant activity, that's easiest if you do a little every day. You're still working against entropy, of course, but as you note that is like every other human endeavour.
There are articles I care about that I don't edit. These are mostly articles that some person or group reckons they "own". I don't edit anything to do with the Middle East, for example, nor any article about nationalist politics. Life's too short. I agreee there's no technical fix for that problem. There doesn't seem to be a social fix either; such articles are presumably just going to remain unreliable. Perhaps Wikipedia just isn't suitable as a repository for certain kinds of information.
Incidentally, articles on food seem to get nationalists going. The article on Biryani, for example is the subject of constant drive-bys, constantly flipping back and forth between India, Persia and Pakistan.
> constant AFDs and DRN attempts
what does this mean?
I think the edit history is quite harmless on this article at least.
Well, the biggest error for me is that the tongue-shaped region is completely filled with color! On any three-color device like an LCD display, the gamut of producible colors will cover a triangular region inside that tongue. Any chromaticity diagram that is filled completely is a lie.
It's hard to call that an error. Do you want it to show garbled static? Every point on the diagram shows the closest available color based on the format.
Well, you would not be able to see "mud":
Out of curiosity...what background do you have to make such a wonderful highly technical comment in a casual way...I'm so interested in the field of your expertise that you know so much about that this stuff, that something so technical is familiar to you, that you can come up with this brilliant analogy straight away and do it so casually. Do you work in "color technology" for a media company or something? I have no idea. I'm so interested what part of the world people who know these things do work in.
Strangely, I'm struggling to write this comment in a way that doesn't sound trolling...sorry, I don't mean trolling at all. If you could see my facial expression it would be easier...
I think we should normalize expressions of awe and curiosity about other people. It's hard to do without sounding ridiculous. A model that helps me is, "I like the state that that person's brain is in. I'll let them know. If I'm lucky, my communication of appreciation might shake out some generalizable knowledge that I have not encountered before."
A good set of people to practice this on is doctors, teachers and Twitter users you admire.
I'm not the parent you're asking, but figure you might be interested anyways since I could've likely made the same comment:
I work on displays within an OS team. Having some basic understanding of colour theory is critical for a significant number of modern display projects, particularly for the high end. For example, enabling colour accurate rendering (games, photos, etc), shipping wide-gamut displays (how do you render existing content on a WCG display?), etc. More specifically to the planckian locus, it generally comes up when deciding which white point to calibrate a given display to at the factory (e.g. iPhone is 6470K, S20 is 7020K in Vivid) and if you're doing any sort of chromatic white point adaptation, like Apple's True Tone.
My background before joining the team was a degree in math, but I really enjoyed doing low level projects in my spare time, so ended up on an OS team. We also have colour scientists who study this full time and have a _significantly_ better understanding of it all than I do :)
: https://www.displaymate.com/iPhone_13Pro_ShootOut_1M.htm#Whi... : https://www.displaymate.com/Galaxy_S20_ShootOut_1U.htm#White... : https://support.apple.com/en-gb/HT208909 : http://yuhaozhu.com/blog/chromatic-adaptation.html
I'd wager bachelor's degree+ in applied math or pure math or maybe physics.
Someone should implement a Planckian locus color space.
Ye olde incandescent bulbs had this built-in, of course you needed a dimmer...
I turned mine up to infinity and they had to build a new Earth. (These kids with their 11!)
Most programmable home LED lighting (e.g. Hue) provides a one dimensional color temperature color space.
I have just computed the colour and find slightly different value, i.e. computed [154, 181, 255] vs article [148, 177, 255]. Here is a Google Colab Notebook that has the colour for 10^200 along with comparisons with a blackbody:
David Madore answered on Twitter : https://twitter.com/gro_tsen/status/1483054395524796421, the discrepancy is likely due to you using Python's colourscience package SPECTRAL_SHAPE_DEFAULT which is based on ASTM E308-15 based on CIE and him using better color conversion functions from http://cvrl.ioo.ucl.ac.uk/index.htm
Yes, and as discussed on Twitter, sRGB is defined for the CIE 1931 2 Degree Standard Observer, not other observers. It is not defined spectrally but as a set of chromaticity coordinates (in the CIE 1931 Chromaticity Diagram). Thus, strictly speaking, sRGB values can only be computed for the CIE 1931 2 Degree Standard Observer. I tried four different observers, using strict integration:
- CIE 1931 2 Degree Standard Observer: [ 153.9026317 , 180.75617631, 255. ] - CIE 1964 10 Degree Standard Observer: [ 150.32288938, 184.67113624, 255. ] - CIE 2012 2 Degree Standard Observer: [ 145.14899585, 180.69807338, 255. ] - CIE 2012 10 Degree Standard Observer: [ 148.44893332, 185.66849549, 255. ] - Article: (148,177,255)
> strictly speaking
Perhaps think of it as two steps? One of physics and biology, using minimally-flawed spectra, CMFs, and math, to get a plausible chromaticity. And a separate step of communication, using standards of sRGB and image ICC tags (rendering intent), to get browsers to convey that chromaticity to the user as a minimally-misleading (for the use case) color.
Thus the 10 vs 2 deg CMF choice might depend on the physical angular size of the emitting area. And before browsers supported rendering intent, for use cases where users were eyeball comparing the color with screen white, one might calculate using a very non-standard D58 white-point, as the blue-ish D65 would make white chromaticity render as a pink color, with users misled to think the chromaticity was pink.
After a great discussion on Twitter, it comes down to normalisation: I normalised the final EOTF-1 sRGB encoded values while the author normalised the intermediate linear sRGB values and did the EOTF-1 encoding after. We used the same Standard Observer.
Well, 10^200K isn't quite infinity yet.
Have you checked if the values change if you increase the temperature even further? Looks like their color is bluer than yours at least..
Yes, it is minimal.
I swear it's Periwinkle like the flower.
weird, several years ago i had a dream i had entered some kind of device that started to accelerate me towards the speed of light, and at the end of it i came to a point where it reached 'infinity' and it was like the most electric intense thing i had ever experienced, and i made a webpage to try and recreate and document what i remembered, and the color is almost exactly the same (strobe / flashing gif warning) http://jollo.org/LNT/public/dream.html
I once had a near death out of body experience and that gif reminds me of it like nothing else I've seen.
My out of body was from hallucinogens rather than near death, but it was very similar as well. The strobing is fascinating, going from a place of undifferentiated light back to the material world and back at a specific frequency.
Ah jeez that's a very flashy GIF at the end of the page there. Might want to throw a sensory warning on that link as a courtesy
I can't help being reminded of the passage in the book of Revelation where John describes the throne room of God, and he notes "a rainbow round about the throne, in sight like unto an emerald".
That's a little hard to imagine, because a rainbow contains a full spectrum of colours, whereas an emerald usually has a single colour, so some translations interpret the rainbow as being like the shine/gleam/glow of an emerald. But the idea that at infinite energy a spectrum might be perceived to human eyes as a single bluish hue is a nice thought, like the coincidence(?) that this colour happens to look like a clear summer's sky.
Anyway, for comparison, here's an image from Wikipedia of a synthetic emerald:
The Greek term here is "ἶρις κυκλόθεν". According to Liddell-Scott "ἶρις" ("iris") may not only mean specifically the rainbow, but "any bright-coloured circle surrounding another body". So the emphasis is not on the spectrum, but on the shape. A better translation would be: "and the throne was completely surrounded by an emerald circle."
I am wondering how many other "theories" of the Bible are similarly ill-informed.
Probably many, but my understanding is that the prophets "visions" aren't really meant to be taken literally: god is supposed to be this thing outside of reason and perception (not a "thing" actually), the visions are what the prophet's human mind makes up: throne, gold, rainbows and stuff aren't what the divine _actually_ is, it's just how the prophet's human mind visualises it. Also sometimes descriptions of visions are symbolic, which means these descriptions are as far from the vision as the vision is far from "actual" god.
(History of God is an interesting book, even/especially for atheists)
It's a nice thought, but describing the color in the OP as emerald seems like it would be a fairly poor attempt at describing your vision. It's more of a cornflower blue, or even as you say (and something easily accessible to the ancients): the color of a clear summer sky.
For example if I was John and I saw the color of infinite temperature around God's throne, I would probably say something more like:
> and there emanated from the throne an incredibly bright blue halo, as if a clear summer sky was shooting forth from God's throne.
The color blue hadn't been invented yet.
It used to be lumped in with green, fwiw; or rather green was more a cyan or sealike color and they binned everything "cool" together.
How in the world do you have a concept of color and not distinguish between the color of the sky and the color of grass and leaves.
And regardless, my point was more that "emerald" is clearly a worse analogue than "sky" for this particular color.
that's probably true.
Maybe it's just bad writing.
"Perano" is a terrible name. Some far better alternatives:
- catastrophic violet
Well, it's the blue equivalent of pink. Blink? No. Periwinkle? Periwinfinite?
I get super irritated by kids books that teach seven colors. We have an impoverished color vocabulary, as a result. Can't even describe the color of infinite temperature, sheesh.
https://en.wikipedia.org/wiki/List_of_colors_(compact) to the rescue
That list is decidedly NOT cognitively ergonomic. Ends up being worse than useless by giving an appearance of authority.
E.g. look at a periwinkle flower and look at the periwinkle in the list. They call periwinkle "Aero" but what is that?!
I think color names should only be included if they match objects, have historical precedent or are composed of these plus basic descriptors. Or approved by the trans galactic color authority.
This is my go-to page for coming up with names for computers and other hardware. Some examples, past and present: amber, auburn, carmine, cerise, indigo, magnolia, periwinkle, scarlet.
How about “Qabiff”, since it’s #94B1FF. :)
Is it just white? All I see is a white box as the color, though the text says otherwise.
It's blue for me. Sort of a pastel or sky blue.
Yeah, tested on firefox and chrome. It's a pastel blue.
On safari, can confirm it just looks white. Even tried turning off Night Shift.
Not sure if this is a gold dress blue dress situation.
On Safari on macOS it shows a missing image icon and the image source returns a 404 error, so this is not a perceptual thing. In Firefox it does work strangely enough.
What blue dress? It was clearly a gold dress :)
Yes it's absolutely a white box, at least for me on mobile Safari
Same here, mobile Safari.
Huh. I am also using MobileSafari (on iOS 12 and 14) and it is rendering as a blue.
Blue in Firefox.
Baez is also a noted category theoretician - I need to get around to reading https://link.springer.com/chapter/10.1007%2F978-3-642-12821-..., where he claims to find the conceptual framework unifying analogies behind physics, topology, logic, and computation. Discussion: https://news.ycombinator.com/item?id=15423027
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