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[1] is currently malformed[2]. Hmm, and the text incorrect[3].
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[4] 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.
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.
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.
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)[1][2] and if you're doing any sort of chromatic white point adaptation, like Apple's True Tone[1][2].
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://en.wikipedia.org/wiki/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.