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What are OKLCH colors?

jakub.kr

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Re: What are OKLCH colors?

#151

Post by dwringer »

crazygringo wrote: post #150
dwringer wrote: post #143

Earlier quoted context omitted.

sRGB is already not perceptually uniform. These hue changes already happen. Just because the H value in HSL/HSV doesn't change doesn't mean there's no perceptual hue shift when adjusting lightness/value.

I don't know what you're talking about -- that isn't true. There is absolutely no perceptual hue shift in the HSL/HSV models depending on saturation and lightness/value, or when they get translated into sRGB. That's the entire point of HSL/HSV, to isolate hue and hold it constant. HSL/HSV are not perceptually uniform in terms of brightness when hue is changed, or even brightness linearly. But hue is hue. Perceived hu…

There most definitely is perceptual hue shift in HSL (and HSV); it's illustrated quite well at [0](The blog of the creator of OKLab), particularly in [1], an image showing S and L axes while leaving H fixed.

[0]https://bottosson.github.io/posts/colorpicker/

[1]https://bottosson.github.io/img/colorpicker/hsl_blue.png

Re: What are OKLCH colors?

#152

Post by gowld »

Sharlin wrote: post #127
brulard wrote: post #116

Earlier quoted context omitted.

Let's say you continuously change wavelength of a laser from blue (~480nm) to red (~630nm), you are going through green, not through gray. If in your use case going through gray makes sense, that's ok, there may be many paths from one color to another.

In general people don't really think of color in terms of the spectral progression (or the hue wheel), and I don't think that most people intuitively expect a gradient between two colors to pass through another "unrelated" primary or secondary color. The point is somewhat moot though, given that such gradients (like yellow to blue or red to green) are very unnatural anyway.

It's funny and a bit sad because we just went througha decades-long effort to migrate away from jet/rainbow gradients to vik/batlow/bi-hue gradients, and now rainbow is forcing its way back.

https://theconversation.com/how-rainbow-colour-maps-can-dist...

https://www.poynter.org/archive/2013/why-rainbow-colors-aren...

Re: What are OKLCH colors?

#153

Post by gowld »

rafram wrote: post #145
crazygringo wrote: post #140

Earlier quoted context omitted.

> The corresponding values in the HSL swatches are 203 and 227. That is a gigantic difference. Those are totally different hues. Which are, of course, exactly the difference we're seeing.

I'm saying HSL has the exact same shift as OKLCH. And neither is visibly green to me.

It's visibly cyan, isn't it? It's maybe not an intuitive "green" hue (depending on your linguistic culture), but it's clearly different from all the other colors on that chart.

Re: What are OKLCH colors?

#154

Post by itishappy »

layer8 wrote: post #85
cubefox wrote: post #80

Earlier quoted context omitted.

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.

It's an ugly color. Saturation makes stuff pop; this is often desirable. This is why I think it's important to have both polar (OKLCH) and rectilinear (Oklab) gradients.

Re: What are OKLCH colors?

#155

Post by altairprime »

crazygringo wrote: post #139
altairprime wrote: post #118

Earlier quoted context omitted.

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.

No, it's not normal or expected for hue to change when rendering to a limited gamut. It's normal and expected for saturation to change. And for brightness to get clipped. But not for hue to change. That's the critique of OKLCH here, that changing hue is a bizarre and undesirable choice.

Your viewpoint of there being one true way of spectrum gradation under restricted device domains is not universally agreed upon; neither among designers, nor among the ‘normal’ population. No other way is the one true way, either! What works well for a PC sRGB display will be drab and lifeless on a laser cinema projection systems. Printers have faced this problem for centuries and innovated to use glass (long ago) and brushed-metal prints (more recently) as a way to regain control of luminosity independent of saturation and to express their design in less restrictive ways. The only ‘normal’ in this scenario is the shared agreements we make, and the primacy of sRGB’s desaturated brights as the sole exclusive agreement is ending.

(Since this reminded me of it, a random pro tip: For those using macOS Terminal.app, you can redefine the 16 ANSI colors using the full P3 colorspace, so long as you use the full GUI color picker rather than the sRGB-limited #rrggbb entry method. Access to improved saturation helps the eye distinguish different shades in the dim and bright color sets more effectively without having to alter their brightness. It won’t improve the limitations of ANSI color as a whole — the insistence on Luminosity = f(R,G,B) is baked into everyone’s assumptions quite deeply thanks to sRGB! — but it does at least mean you can have seven equidistant and non-desaturated, non-sRGB colors at two levels of brightness for syntax highlighting and other typical 16-color uses.)

Re: What are OKLCH colors?

#156

Post by itishappy »

Sharlin wrote: post #127
brulard wrote: post #116

Earlier quoted context omitted.

Let's say you continuously change wavelength of a laser from blue (~480nm) to red (~630nm), you are going through green, not through gray. If in your use case going through gray makes sense, that's ok, there may be many paths from one color to another.

In general people don't really think of color in terms of the spectral progression (or the hue wheel), and I don't think that most people intuitively expect a gradient between two colors to pass through another "unrelated" primary or secondary color. The point is somewhat moot though, given that such gradients (like yellow to blue or red to green) are very unnatural anyway.

I disagree somewhat. Color mixing just isn't particularly intuitive. It's not the most intuitive to get a third hue, but that doesn't justify grey (which has an undefined hue). I do think most people are quite comfortable with the fact that between blue and yellow exists green, but is it a saturated green or a desaturated green? Additive and subtractive color mixing behave very differently here.

Re: What are OKLCH colors?

#157

Post by itishappy »

layer8 wrote: post #97
the_af wrote: post #90

Earlier quoted context omitted.

Is gray perceived as "just another color" or where all colors go when desaturated? I assumed the latter, which would explain why to avoid it if one isn't playing with saturation.

Think of fashion, of smartphone colors, pen and pencil colors and the like. Gray, white, black, are just color choices among all the available colors. A gray T-shirt isn’t a desaturated colored T-shirt. It’s its own color.

A grey shirt is a desaturated shirt. You cannot resaturate grey.

I think if you buy a tie-dye shirt or phone case and it comes out half grey, despite it being a valid color, most folks will be disappointed.

Re: What are OKLCH colors?

#158

Post by [deleted] »

altairprime wrote: post #155
crazygringo wrote: post #139

Earlier quoted context omitted.

No, it's not normal or expected for hue to change when rendering to a limited gamut. It's normal and expected for saturation to change. And for brightness to get clipped. But not for hue to change. That's the critique of OKLCH here, that changing hue is a bizarre and undesirable choice.

Your viewpoint of there being one true way of spectrum gradation under restricted device domains is not universally agreed upon; neither among designers, nor among the ‘normal’ population. No other way is the one true way, either! What works well for a PC sRGB display will be drab and lifeless on a laser cinema projection systems. Printers have faced this problem for centuries and innovated to use glass (long ago) an…

[deleted]

Re: What are OKLCH colors?

#159

Post by jrm4 »

This is fantastic, can't wait to incorporate it into my web design classes stuff.

Also, I do hope people begin to see the value of "designing toward intuition," I can't help but notice that efforts like these are exact opposite of what happened when (most of) the world forcibly converted to metric.

Re: What are OKLCH colors?

#160

Post by crazygringo »

dwringer wrote: post #151
crazygringo wrote: post #150

Earlier quoted context omitted.

I don't know what you're talking about -- that isn't true. There is absolutely no perceptual hue shift in the HSL/HSV models depending on saturation and lightness/value, or when they get translated into sRGB. That's the entire point of HSL/HSV, to isolate hue and hold it constant. HSL/HSV are not perceptually uniform in terms of brightness when hue is changed, or even brightness linearly. But hue is hue. Perceived hu…

There most definitely is perceptual hue shift in HSL (and HSV); it's illustrated quite well at [0](The blog of the creator of OKLab), particularly in [1], an image showing S and L axes while leaving H fixed. [0] https://bottosson.github.io/posts/colorpicker/ [1] https://bottosson.github.io/img/colorpicker/hsl_blue.png

Well I'll be damned, you're right -- I'm playing with it in Photoshop now, and it seems to be exclusive to hue values of 233-270, in the transition from blue to purple, and nowhere else. Matches what [0] says -- "This is particularly obvious for deep blue and purple colors."

So first, thank you for the correction. It's fantastic to learn something new. And second, do you have any idea why the OKLCH example on the page is so atrociously bad? The way blue changes to cyan is even worse than the HSL/HSV difference of blue-purple. It's like the cure is worse than the disease. If they were so concerned with hue fidelity in the first place, I'm surprised they wound up producing an end result just as bad.

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