The “Better Gradients” thing is dodgy.
OKLCH is a polar coordinate space. Hue is angle in this space. So to interpolate hue from one angle to another, to get from one side of a circle to the other, you go round the edge. This leads to extreme examples like the one shown:
linear-gradient(in oklch, #f0f, #0f0)
linear-gradient(in oklch longer hue, #f0f, #0f0)
Accordingly, there are algorithms defined (yes, plural: not every application has agreed on the technique to use) to drag the colour back in-gamut, but it sacrifices the perceptual uniformity. The red in that gradient is way darker than the rest of it.
When you’re looking for better gradients, if you’re caring about perceptual uniformity (which frequently you shouldn’t, perceptual colour spaces are being massively overapplied), you should probably default to interpolating in Oklab instead, which takes a straight line from one side of the circle to the other—yes, through grey, if necessary.
linear-gradient(in oklab, #f0f, #0f0)
During its beta period, Tailwind v4 tried shifting from sRGB to Oklch for gradient interpolation; by release, they’d decided Oklab was a safer default.
>During its beta period, Tailwind v4 tried shifting from sRGB to Oklch for gradient interpolation; by release, they’d decided Oklab was a safer default.
I recently implemented both, first I started with OKLab which turned out really well, the gradients you get from it are amazing and the usual color sets (analogous etc.) produce really pleasing sets.
However I quickly ran into the main problem with it, which is that fiddling with its Lightness, Chroma and Hue dials doesn't produce human understandable results. For example sometimes changing L or C induces a color shift, or for some given values changing L only gives midrange values that doesn't go up or down all the way.
I then implemented OKLCH on top of that, which was the way I assumed everyone was doing it. Just have it act as the controller for the human layer, then convert to OKLab for creating gradients etc. The article doesn't really go into it, but having OKLCH as the frontend controller fixes the LCH sliders such that they produce values that make sense to us humans, while still having the superior OKLab setup in the back.
Also, isn't the way browsers interpolate colors in sRGB just a bug that I assume is retained for backwards compatibility? sRGB is a logarithmic encoding, you were never supposed to interpolate between colors directly in that encoding - the spec says you're suppose to convert to linear RGB first and do the interpolation there...
It's not a bug, its a property of the colour space. Which is partially tied to how the colour is represented (RGB). When doing linear interpolation through the RGB cube (for eg a gradient), you normally pick the shortest path. It just so happens that sometimes that path passes thorough some shade of gray as different colour components are scaled.
Usually you fix it by moving your point through a different colour space. Choice depends on your requirements and mediums you're working with (normally different types of light sources or screens).
I had to write a low level colour interpolation librar for a few interactive art projects, so I dipped a bit into this, but I'm no colour expert
No, sRGB refers to both a colour space and an encoding of that colour space. The encoding is non-linear to make best use of the 256 levels available per channel, but you were never supposed to interpolate sRGB by linearly interpolating the encoded components: you're supposed to apply the transfer function, perform the linear interpolation at higher precision, and then convert back down into the non-linear encoding.
Failure to do this conversion is what leads to the bad results when interpolating: going from red to green will still go through grey but it should go through a much lighter grey compared to what happens if you get the interpolation wrong.
I think GP is referring to the difference between "normal" (gamma-encoded) sRGB and linear sRGB. Though it's not logarithmic but a power law. In any case linear interpolation done in non-linear sRGB gives you intermediate colors that are darker than they should (though historically it's been so common in computer graphics that people are accustomed to it).
This is super insightful, thank you! I wrote the article and will make changes to explain this better :)
IMO in pretty much all cases if the two colors at the end of your gradient are not already very close, you will always get the best results by manually specifying the colors at one or more steps between the two original colors.
Which brings me to point at the crux of the matter: avoid gradients between two dissimilar colors in the first place.
We already have CIE LAB as a standard that does the same thing... https://en.wikipedia.org/wiki/CIELAB_color_space
[EDIT] Ahh.. The W3C has already looked at this. https://www.w3.org/Graphics/Color/Workshop/slides/talk/lille...
For others, I'm sure parent knows: OKLCH is largely a bugfix for CILEAB. Both try to make a color space where even steps feel evenly spaced to a human. But CIELAB had procedural flaws in its creation.
See slide 19: https://www.w3.org/Graphics/Color/Workshop/slides/talk/lille... -- if you ask CIELAB to make "pure blue" (RGB 0 0 100%) become grayscale, the intermediate colors become purple to the human eye. The entire point of a perceptual color space is that that doesn't happen. OKLCH fixes that.
BTW, credit to Björn Ottosson, who basically side-projected a color space into the web standards and more: https://bottosson.github.io/posts/oklab/ ... folks like him are why we sometimes have nice things!
For anyone else copy pasting the gradients into dev tools to look at them: The second one is missing the # sign on the first color.
And yes, both oklch gradients look pretty weird while the oklab gradient looks nice (if you can accept it going through grey).
Can anyone share some images for those who don’t have dev tools to view them?
Sorry, fixed.
But what really is a "color gradient"?
Isn't it any continuous function that starts at a specified color and ends at another specified color?
How then does one say that any gradient is good or bad?
Isn't the problem you are highlighting guaranteed to exist for any colorspace that defines colors outside of human perception?
A good gradient is one that takes a perceptually uniform, and typically perceptually shortest, path. The OKLCH gradient isn't perceptual uniform and appears to take unnecessary detours through other hues.
One could also argue that the detour through other hues is necessary in this case to avoid going through grey.
Gray is arguably just another color, it’s not clear why you’d want to avoid it. How is going via red and yellow better than going via gray? Varying hue is often perceived as a larger change than varying saturation or lightness. A path going through several distinct hues is visually less uniform than one going through gray once.
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Interesting. In nature, I suppose I am most aware of a gradient from a saturated azure sky above to a much whiter sky on the horizon. This would seem to be a trivial saturation gradient.
For a spot color (from a gel covering a light) the light diffuses further from the center of the projected light — two spot colors (with different gels) then, next to each other, would give a kind of gradient from one color to the next as you walk a line from the center of one light to the other.
I wonder what the closest analog to this is algorithmically?
I guess where I am going with this is: is there precedent in nature as to how gradients are supposed to work (and therefore an analog which we should try to model) or are we going strictly on how the human eye perceives color and what algorithm we think "looks" right?
Edit: The article was updated. Ignore me.
> you should probably default to interpolating in Oklab instead
The article says as much. Quoting:
> This can be a double edged sword. While some gradients might look smoother, you might also see colors that you've never defined. This is because hue in OKLCH is circular and gradients can take unexpected detours.
> To avoid this, many tools use OKLAB for gradients, which interpolates in a straight line and gives more consistent results.
I was going to point that out too until I realized that the author updated the article based on the parent comment!
https://news.ycombinator.com/item?id=45013291
Ha! Well spotted.
Making a gradient from two colours on opposite sides of the spectrum is a bit of a pathological case. There's no obvious answer what it "should" look like, and also no good reason you'd really need to do this. If you're using a gradient as a design element, you'd pick your own midpoints.
Very interesting. Is this just a limitation of our current hardware? How much of this problem would still exist if everyone had a wider gamut monitor, say full DCI-P3? That still doesn't cover the full gamut of Oklch, but would it make the problem practically disappear?
No. We’re talking about colours way beyond the ranges of human perception.
For this specific gradient, see https://oklch.com/#0.7017,0.3225,328.36,100 and https://oklch.com/#0.86644,0.294827,142.4953,100, and look at the Chroma panel, see how far out of our screen gamuts they are (even tick “Show Rec2020”, which adds a lot of chroma around blue–green and magenta–red), and try to imagine the colours between the lime and magenta (in either direction). The red direction is probably the easier to reason about: there’s just no such colour as a light, bright red. You can have bright or light, but not both. (Its 3D view can also be useful to visualise these things: you’re building a straight-line bridge between two peaks, and there’s a chasm in between.)
I don't get it, why am I seeing the "out of gamut" colors if my sRGB monitor is unable to display them? Would the charts look different on a P3 monitor?
edit: Also, you mentioned the colors "beyond the ranges of human perception" but I don't think there is any such limitation here, the bottleneck is the hardware (computer monitors).
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Wow, I never thought about bright light red when thinking of undisplayable colors. It makes a lot of intuitive sense, thanks!
But once an algorithm to drag the colours back in-gamut was applied, would the lost perceptual uniformity still be a problem practically speaking, with DCI-P3 monitors?
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The underlying problem is that the color space humans can see doesn’t have nice uniform linear boundaries. The larger your color space, the more relevant that issue actually becomes.
RGB is just allways worst OKLCH usually pretty, which is all I want from gradients most of the time.
I had claude build me a comparison (not sure why 2x the same HSL one) https://i.imgur.com/uziQibR.png
Also super hard in RGB: https://jsfiddle.net/nhgvzm5p/2/ it's just a 2 color OKLCH gradient:
oklch(0 0.07 279) 66%,
oklch(0.98 0.09 276) 99%That gradient looks terrible, very bad colour banding, because you’re starting and ending at points that are way out of gamut, and the technique used to bring it in isn’t smooth. For a gradient like that, you probably want at least five points.
That is the biggest problem with these colour spaces: the edges are unclear, and overflowing them has bad effects.
you think I can get the same OKLCH style colors but without banding?
if I sample 5 colors and throw them in as rgb?
the 3 color rgb one has very similar banding
my biggest problems with OKLCH:
- how to easily add "warmth". you can't just add red+green - no good tools for it (e.g. a nice gradient picker ui that lets me specify if I want to allow running out of bounds of teh color space and clip a few colors at max saturation)
> The red in that gradient is way darker than the rest of it.
It doesn't look significantly darker to me.
Great post!
Also check out oklch.com, I found it useful for building an intuition. Some stumbling blocks are that hues aren’t the same as HSL hues, and max chroma is different depending on hue and lightness. This isn’t a bug, but a reflection of human eyes and computer screens; the alternative, as in HSL, is a consistent max but inconsistent meaning.
Another very cool thing about CSS’s OKLCH is it’s a formula, so you can write things like oklch(from var(--accent) calc(l + .1) c h). Do note, though, that you’ll need either some color theory or fiddling to figure out your formulas, my programmer’s intuition told me lies like “a shadow is just a lightness change, not a hue change”.
Also, OKLCH gradients aren’t objectively best, they’re consistently colorful. When used with similar hues, not like the article’s example, they can look very nice, but it’s not realistic; if your goal is how light mixes, then you actually want XYZ. More: https://developer.mozilla.org/en-US/docs/Web/CSS/color_value....
Also, fun fact: the “ok” is actually just the word “ok”. The implication being that LCH was not OK, it had some bugs.
> Another very cool thing about CSS’s OKLCH is it’s a formula
While it’s more useful for a perceptual color space, relative colors are supported for all CSS color spaces e.g.
background-color: rgb(from var(--base-color) calc(r - 76.5) g calc(b + 76.5));OKLCH plus relative colors let me seriously reduce the amount of hardcoded colors from my style sheet:
https://github.com/hazelgrove/hazel/blob/dev/src/web/www/sty...
Aside from a few criticisms that others have already raised I think this is quite a nice introduction to OKLCH and how to use them in CSS.
With that out of the way, I'd like to go on a tangent here: can anyone explain the modern trend of not including publishing dates in blog articles? It stood out to me here in particular because the opening sentence said that "OKLCH is a newer color model" and the "newer" part of that sentence will get dated quicker than you think. The main site does mention a date, but limits it to "August 2025" so this seems like a conscious choice and I just don't get it.
> can anyone explain the modern trend of not including publishing dates in blog articles?
In such cases, I usually try to see if the `Last-Modified` header served with the HTML document over HTTP, can be useful, but I conclude that often the same people who don't bother with dating their content -- you'd think they'd understand where the word _blog_ comes from, as in "[web]-log" where timestamps are paramount -- these same people don't know or care how HTTP works. Hint: the `Last-Modified` is the last modification time of the _resource_, in this case the actual HTML document. Just because your "backend" re-rendered the content because you didn't bother with setting up your server caching correctly, doesn't mean you should pretend it's a brand new content every day (which https://jakub.kr/components/oklch-colors does, unfortunately, so you won't know the timestamp from HTTP).
I would imagine this is rather to whatever "blog engine" is used instead of the conscious choice of the author (even if they knew what they desire and what would qork better, it might not be their priority).
I can't explain it, but undated articles are a serious problem. I don't know whether it's a modern trend ... how can one tell in the absence of dates? I've seen plenty of undated content that appears to be old.
On some blogs I can only tell the timeframe of the content from the timestamps on the comments ... but many blogs like the OP's don't support comments. I'm not likely to revisit them. (The blurb on the OP's main page is ironic ... rather than obsessing over the smallest details I see obsession over esthetics to the detriment of functionality.)
SEO to protect old content from being demoted. It is annoying.
I'm surprised they don't punish undated articles then
Blame Google and SEO
I found this to be a good article on the subject:
https://evilmartians.com/chronicles/oklch-in-css-why-quit-rg...
Along with their picker / converter here:
Discussed on Hacker News here:
https://news.ycombinator.com/item?id=43073819 (6 months ago, 30 comments)
> In the example above, you can see that the OKLCH colors maintain consistent blueness across all of the shades, while in the HSL example, the lighter shades drift to purple and the darker ones muddy out towards grayish.
There is a very clear shift towards green in the OKLCH lightness value change example, enormously more so than any purple vibe in the HSL example.
Clearly being able to select colours of the same perceptual intensity has value, but some of the claims here as to the benefits are exaggerated.
You can see why by looking at the Hue chart for this color:
https://oklch.com/#0.7684,0.1754,218.1,100
To increase brightness past the limit of the Hue band for the color, the rendered output color on a display shifts cyan due to the limited brightness range of a saturated blue in the Display P3 color space. OKLCH is, when varying brightness along a gradient, Saturation-invariant rather than Hue-invariant; whether that effect is desirable is a matter of aesthetic preference, but after decades of Hue-invariant desaturated web color, it’s certainly refreshing to have a choice about which compromised invariance to take.
https://news.ycombinator.com/item?id=44588388
Science recently invented a much-deeper blue LED than we have now, so I expect in a decade or two, whatever ends up succeeding Display P3 will be much more able to represent that gradient without cyan-shift, and all of the years of OKLCH gradients created before that time will end up showing a more accurate blue gradient with only the colorspace change. In the meantime? Do whatever’s aesthetically pleasing; there is no Right Answer in design :)
ps. One could argue that a post-OKLCH colorspace should not accept the binary decision of Hue or Saturation invariance, and instead should be Saturation-invariant to the display’s native limit and then transition smoothly to Hue-invariance at that threshold. I believe that’s a Difficult Problem in color profile specification terms, since it isn’t just pre-calculating the changeover threshold for all monitors (not to mention, do you change blue sooner or same as red, etc) but it’ll be a while longer before I’m versed enough in ICCv4 to explain that perception. It sure would make for an interesting experimental DisplayCAL target, though!
> You can see why by looking at the Hue chart for this color
This misses the point: the example claims the hue isn't shifting, when it very clearly is. It's not a question of why.
The hue isn’t shifting in OKLCH at all; also, it’s definitely shifting when OKLCH is rendered to Display P3 or sRGB. This is normal and expected behavior for colorspace gradients when rendered to device profiles? But I suspect I’m too close to the problem to see what’s not explained properly, apologies.
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There’s no green shift at all in that example on my display. Could your calibration be off?
It's practically cyan, which is half way to green, not a lighter version of the blue to the left. This is on a MBP built in display.
This totally has uses but it is not, as claimed, "there is no hue or saturation drift" given the hue has shifted so much.
There certainly is ... run a color picker over it.
I opened the macOS Digital Color Meter and set it to "native values" mode. The second-to-last OKLCH swatch has a green component of 202, and the last has a green component of 226. The corresponding values in the HSL swatches are 203 and 227.
Basically no difference at all.
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Agreed. The hue changes completely from blue to cyan.
If that's a correct implementation of OKLCH, then it's not something I would ever touch. Something seems to be deeply wrong with however they're calculating hue.
HSL/HSV have issues with perceptual lightness. But not with hues. The hue is constant and doesn't need any correction depending on saturation or lightness.
I think you do usually want to rotate the hue a bit when changing the lightness though. It’s a difficult thing to get right and one of the reasons the tailwind builtin colour palettes are so useful.
You don't. That's not something graphic designers ever do as compensation for perceptual uniformity.
I looked into it a bit more, and it turns out it's a result of OKLCH easily producing colors out of gamut, and then choosing to sacrifice hue accuracy for better saturation accuracy.
That's a fundamental design flaw if you ask me. Changing hue is completely unacceptable in my book.
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I don't know much about the science of colors and I imagine this is going to be very subjective but I would at "worst" describe the rightmost OKLCH color as blue-green (but probably just "light blue"). Meanwhile the two rightmost HSL colors I would not describe as blue at all. Second from right I would call "light purple" and the rightmost honestly looks grey to me (which is weird because the caption says the darker HSL values "muddy out towards greyish" but the leftmost values for OKLCH and HSL both look pretty blue to me).
Also if I use the macOS app "Digital Color Meter" I get essentially the same green value for the rightmost OKLCH and HSL colors (226 and 227 for "display native values" and 228 and 227 for sRGB).
OKLCH: a color model based on OKLab (a perceptually uniform color space) where you control Lightness, Chroma (saturation), and Hue.
"OK" because "it does an ok job" according to its creater Björn Ottosson.
He’s Swedish, so I bet OK is actually short for “Ottossons kulör” but he’s just being modest.
In the spirit of "Oll Korrekt", "Otto's Kolors"?
How do you pronounce it, btw? "Oklich"? "okay L.C.H."?
Lich is an old word for a corpse (or in D&D mythology an undead magician).
An okay lich is like a chill corpse, maybe?
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Wherever you're working with colors and text/emblems, please also consider contrast and legibility: <https://apcacontrast.com/>
While the above site is great for measuring with a modern contrast algorithm (it’s the current algorithm for the yet-to-be-released WCAG 3 accessibility standards), it’s worth bearing in mind that the WCAG 2 algorithm is somewhat different, and a legal requirement in many markets / industries. You can check your colours against that with a tool like https://www.siegemedia.com/contrast-ratio, although there are many more.
Any reference to APCA has been removed from the WCAG 3 drafts in 2023 (see https://github.com/w3c/silver/commit/d5b364de1004d76caa7ddc4...).
I am not sure what the status is.
Oh, interesting, I’d missed that. Good info, thanks!
You can pick colors that pass both APCA and WCAG contrast checks though so it's not a problem to use APCA recommendations now.
I find APCA is a little stricter than WCAG for light themes, and APCA is much stricter than WCAG for dark themes, to the point where you really shouldn't use WCAG for dark themes. So most of the time APCA is giving you stricter contrast that easily pass WCAG also.
I keep seeing mentions that APCA will let you finally use e.g. white on orange, or white on vibrant blue that pass APCA but fail on WCAG, but my feeling is there's not a lot of examples like this and most of these pairings only have okay contrast anyway, not great contrast, so it's not ideal to be stuck with WCAG's false negatives but not that big of a deal.
If your colours have enough contrast to pass them both then of course that’s fine!
I only bring it up because I had a situation last week where the better APCA was giving results for both white-on-colour and #111-on-colour as suitable for headline copy under WCAG3, but #111-on-colour was 7.5:1 and white-on-colour was 2.5:1 under WCAG2, hence we could only use one of them legally.
> I only bring it up because I had a situation last week where the better APCA was giving results for both white-on-colour and #111-on-colour as suitable for headline copy under WCAG3, but #111-on-colour was 7.5:1 and white-on-colour was 2.5:1 under WCAG2, hence we could only use one of them legally.
Yeah I understand, would you agree this is fairly rare when using APCA though?
I've had the opposite where the brand guide was suggesting we use a light on dark combo that passed WCAG2, yet it failed APCA, and worst of all clearly had poor contrast just by looking at it. Yet, some people will still go with it because WCAG2 gave it the okay haha.
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On the comparison between Color spaces, it's weird, my monitor from 2008 does show a difference between the Display-P3 and the sRGB purple colors, yet I didn't think it'd have such a big color range. Is there some color conversion at the browser or OS-level? (my distro/desktop enables colormgr by default).
It’s just completely wrong.
The first uses oklch(0.65 0.20 300), comfortably inside sRGB, not even at the boundary. The second uses oklch(0.65 0.28 300), which is well outside P3 and even Rec.2020.
The smallest fix would be to make the second one oklch(0.65 0.2399 300) to bring it inside P3 so the demo doesn’t get slightly warped if Rec.2020-capable (not really necessary, but preferable, I’d say), and the first #a95eff (oklch(0.6447 0.2297 301.67)) which is CSS’s fallback.
But purple is also pretty much the worst choice for such a demo—P3 adds the least to sRGB around there, so the difference will be smallest. A better choice is red or green.
So a better pair would be oklch(0.65 0.2977284 28) on the right (a bright red at the very edge of the P3 gamut, well outside sRGB) and #f00 on the left (the sRGB value CSS will map it to if out of gamut).
Sort of off topic questions, do we have any upcoming colour space beyond BT2020, now that we soon have monitor that reach 100% BT2020. I did some search and it doesn't seems to be any.
For any really bigger color space, you would have to use more than 3 primary colors, which would increase a lot the cost.
Moving the monochromatic BT.2020 colors from 630 nm, 532 nm and 467 nm could get a little increase in color space coverage, but at the expense of a lower efficiency in power consumption to brightness conversion. 467 nm is not a very pure blue, but the sensitivity of the eye drops very quickly in the blue region, so a better blue would require much more power. Similarly, though not so pronounced, for a different green.
Moreover, in the green region there is a gap, both for lasers and for LEDs, where the available devices have low efficiencies for converting electrical power to light, so changing the frequency of the primary green color would have to take that into account too.
In conclusion, I believe that the BT.2020 (actually BT.2100) color space is close to the best that can be done in displays of reasonable price and energy efficiency.
A true coverage of 100% of the BT.2100 color space can be realized only with laser projectors. Any display with LEDs or quantum dots will never have really monochromatic primary colors, though a coverage of significantly more than 90% of the BT.2100 color space is not too difficult. However, the advertised percentage of the color space may be misleading, because it varies depending on the kind of color space used for computations. A coverage percentage computed in OKlab would be more informative than a percentage computed in the XYZ color space.
> For any really bigger color space, you would have to use more than 3 primary colors, which would increase a lot the cost.
Unless you want to make displays for the bees and birds (and the tiny alleged minority of human tetrachromats) that seems rather pointless. People with three color receptors are your customers, so that's driving the market.
I rather predict, future displays will further improve on contrast, including very bright (brilliant) sparks. Imagine an iPhone glittering like gold or diamonds ...
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This should be fixed now as well!
Good, much improved.
One last thing:
> This way the browser uses OKLCH colors if they are supported, otherwise it falls back to sRGB.
This wording suggests it’s about gamuts, but it’s actually about syntax. It will use the oklch() if that syntax is supported, and then the OKLCH value may be within sRGB or may be in another gamut the screen is using or may need to be mapped back to the screen’s gamut. Whereas #rgb values are inherently limited to sRGB, the baseline.
I tried working with it but had to give it up for practical purposes. Whereas the focus with HSL is on the Lightness part and the Saturation is made to fit, OKHCL does it differently. It pushes the Chroma part to it's technical limits and abuses the Hue to make it fit, but we just do not understand Chroma intuitively. I am waiting for OKHSL where the adjustments will bu much smaller and do not lead to absurd changes in intent. I already had a discussion about it somewhere else (https://www.reddit.com/r/css/comments/1jv5f0r/hue_is_an_issu...)
My mind immediately translated OKLCH into "Oklachroma".
For historical "neat" factor, here's the original blog post that introduced the color space:
Why is there no documented formula to convert to from this color space? A quick google and the best I could find is this Gist[0]. Searching for Oklab has a Wikipedia page[1].
[0] https://gist.github.com/dkaraush/65d19d61396f5f3cd8ba7d1b4b3...
[1] https://en.wikipedia.org/wiki/Oklab_color_space
It looks to me that all the "magic" is in the matrices used for conversion between Oklab and sRGB. The final conversion between Oklab and Oklch is trivial, and is documented in your linked Wikipedia article.
OKLCh is the same space as OKLab, it's just polar coordinates versus rectangular coordinates.
That gradient example is hilarious.
With RGB you order green salad you get green salad.
With OKLCH you order green salad you get beet soup.
Yes ... see chrismorgan's comment on it up top.
Nice post. OKLCH is quite handy but for writing colors in CSS I hope eventually we’ll get some form of OKHSL/OKHSV[1] so users don’t need to worry about gamut boundaries.
There is a youtuber (Gneiss Name) making educational content through the medium of Minecraft. He's made one on OKLab as well: https://youtu.be/nJlZT5AE9zY
What an absolutely fascinating channel! Thanks for the link
I've not touched oklch, but I've played with oklab gradients a fair amount.
How do they (oklch & oklab) compare for different uses?
oklch uses the oklab color space.
The oklch color space is polar: it’s a cylindrical transformation of the oklab cartesian color space.
That's quite misleading. The parent commenter was asking about gradient (interpolation between colors). Gradients look completely different in oklch and oklab.
Well yes, it's a different coorsinate system, so gradients would look different. It is still the same color space, but I agree I could have worded that better.
Does anyone know how this is different to the Munsell color space, which is also perceptually uniform?
Edit: I would imagine that the only way to definine a perceptually uniform color space is by tons of user testing. This is how Munsell developed his color space… specifically presenting test subjects with pairs of identical and near-identical color swatches and asking if they could tell the difference.
In this way, pairwise comparisom of similararity became the bedrock of color perception science.
The Munsell color system isn't really intended for displays, rather it's a collection of pigments, similar to Pantone. The transforms can get a bit weird (for example, since the swatches are discrete, there's no defined way to get intermediate colors). Munsell's ideas, particularly the axes of hue, value, and chroma, have absolutely influenced modern color spaces and are very much on display in the OKLCH space.
Oklch is open source and part of the web standard, Munsell colors probably needs a licence to be used ?
My understanding is that it's the same with higher resolution.
Really happy about oklch. You do have to learn the hue numbers, but once you do, everything is more intuitive.
The best axis for Lightness in my opinion is still the Gray-Scale (as used back in the day for black/white/grayscale TVs).
The newer CIE colorspaces (CIECAM02 CIECAM16) seem to address the effect, that color-perception goes wild if you change background and illumination. Oklab seems to only make some fixed choice about how to include the chromatic part to lightness. I'm not so sure, how this definition of lightness is any better than grayscale (from 1931).
Creator of OKLCH on OKLCH: