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Posted by moultano 14 hours ago

Where to Find the Colors Your Screen Can't Show You(moultano.wordpress.com)
357 points | 90 comments
adrian_b 9 hours ago|
While it is true that some saturated blue-green colors will never be reproducible with only 3 primary colors, the CIE 1931 chromaticity diagram used in TFA overemphasizes their importance, because human vision cannot distinguish many colors in that area of the diagram.

In reality, the greatest defect of the sRGB color space, which is still too frequently the default color space, is that it is not able to reproduce many saturated orange/red/purple colors, which are very frequently encountered around us, e.g. in flowers, fruits and clothes.

The missing orange-red-purple corner appears small in the diagram in comparison with the missing blue-green corner, but in reality humans perceive much more different colors in the orange/red/purple corner, so the relation between those areas would be opposite in a uniform color space.

The Display P3 color space is much better than sRGB for reproducing orange/red/purple colors and now it is available even in many cheap monitors. However many monitors that can reproduce Display P3 come configured by default to use just sRGB. Such monitors should always be reconfigured to use Display P3.

Monitors that can reproduce an even greater part of the Rec. 2020 color space are obviously better than those that can do only Display P3, but such monitors with a higher color gamut are usually more expensive. The full Rec. 2020 color space can be reproduced only with laser projectors, because it uses monochromatic primary colors.

js2 1 hour ago||
> The full Rec. 2020 color space can be reproduced only with laser projectors, because it uses monochromatic primary colors.

All of the non-commercial triple laser projectors I'm aware of are single-chip DLP, so they suffer rainbow artifacts and have poor black levels. They're also liable to laser speckle[^1] if you're not careful on your screen selection.

The JVC (LCoS), Sony (LcoS) and Epson (LCD) laser projectors all use a single blue LED laser and phosphor wheel to make white light, then use prisms and filters to split it to RGB and can only get 87-98% of DCI P3. They have better blacks and no rainbow artifacts, but the color reproduction is not as complete.

Which is to say, it's still a compromise in projector land, unless you've got $400K for a https://www.christiedigital.com/products/projectors/all-proj...

[^1]: https://www.valerion.com/blog/triple-laser-speckle

jfengel 20 minutes ago|||
As I understand it, JPEG cuts out a lot of detail in the blue range, because we don't see it as well. Is that due to the same thing as you're saying here?
Dwedit 6 minutes ago||
That has more to do with RGB -> YCbCr conversion, and how much blue contributes to Y (brightness). JPEG is a different thing, it turns YCbCr images into blocks made up of DCT patterns, and the chroma blocks are often half the resolution of the luma blocks.
red75prime 8 hours ago|||
> the relation between those areas would be opposite in a uniform color space.

If I understand correctly fig. 3 in [1] should be perceptually uniform. The bluegreens missing from sRGB, but present in BT.2020 comprise a sizeable chunk comparable to redyellows.

[1] https://www.researchgate.net/publication/345252499_Evaluatin...

adrian_b 5 hours ago||
Indeed, "Figure 3" from that article should be a realistic depiction of the differences between sRGB, Display P3 and BT.2020.

It is true that both the red and green primary colors of sRGB are bad (because they correspond with obsolete CRT phosphors that have not been used for decades), but in practice the defects of the green primary color are much less important, because the objects with saturated green colors are more rarely encountered.

Like I have said, objects with saturated orange/red/purple colors are very frequently encountered, even in most homes, e.g. flowers, fruits, clothes, blood.

Photographs or movies showing such objects that have been recorded using a wider color gamut look extremely differently on an sRGB monitor vs. a monitor supporting Display P3 or an even wider color gamut.

Only very rarely I have seen examples with obvious differences between monitors when showing green objects, e.g. some documentaries with certain vividly colored animals, like some insects, birds, frogs or lizards.

klabb3 5 hours ago||
> Only very rarely I have seen examples with obvious differences between monitors when showing green objects, e.g. some documentaries with certain vividly colored animals, like some insects, birds, frogs or lizards.

According to the article you get purified greens from transmittance through foliage, ie backlight in eg a maple forest. This makes me suspect that it may be more important than just exotic animals, and maybe we are more sensitive to ”greens” than we think? For instance, a lot of my photography of trees/forests tend to feel much more ”green brown mess” and loses structure when going from reality to screen. (Another explanation is that my photos are bad, but I like that one less)

adrian_b 5 hours ago|||
> According to the article you get purified greens from transmittance through foliage, ie backlight in eg a maple forest.

This sounds plausible. I think that in general for content that you record yourself, where you would record whatever is interesting, e.g. the more unusual things, especially outdoors, it is more likely for all the parts of the color space to be important.

My point was that for the content most frequently watched on a monitor, like commercial movies, it is much more likely that the main effect of using the obsolete sRGB color space is to see a lot of objects whose color is in the orange/red/purple area and which appear to have washed-out colors.

In almost any commercial movie, if I switch at almost any point between a Rec. 709 copy on an sRGB monitor and a Rec. 2020 copy on a Display P3 monitor I immediately notice some reddish objects that have become more vivid, looking like in real life, while on sRGB they look abnormally dull.

Until a dozen of years ago, I had used for many years sRGB monitors and I was content with them, but immediately after I used for the first time a Display P3 monitor I could no longer enjoy sRGB photographs or movies, because now their limitations had become obvious.

PebblesRox 1 hour ago||||
I think the lack of depth perception in a 2D photo is another big factor in why the magic of a forest can’t be captured. There are so many different layers that all get flattened!
rbanffy 1 hour ago|||
There is so much going on in a modern digital camera between what the sensor captures and what is stored on the flash card that you might be a perfectly fine photographer and it’s the software in the camera that just doesn’t get your style.
fmajid 6 hours ago|||
Not to mention the Color Rendering Index (CRI) metric Ra does not weigh the R9 (deep red) so many forms of lighting don't try to render it correctly to save costs.
klabb3 5 hours ago||
This is truly an (accidental?) setback of color reproduction as it has progressed over time. For LED lights R9 is also crucial for skin tones which makes it so bad to just leave that out. Now, the mass produced LEDs are even optimized for CRI at all are virtually all excluding R9, which may be one of the main quality issues that many people perceive with LEDs vs eg incandescent. There’s of course more to it but R9 probably has a disproportionate effect for being a ”minor detail”.
NooneAtAll3 2 hours ago||
what's the alternative metric to look for as a consumer?
RedPanda250 2 hours ago||
It is not reported often by the manufacturer, but SSI and TLCI numbers can be a better metric if available. They are used by the Broadcast/Photography community to match the spectrum's similarity to Sunlight.
szmarczak 6 hours ago||
There's color space and there's color depth. You may be using D-P3 with 8 bit, which is worse (less accurate?) than sRGB with 8 bit. And there's bandwidth. Your monitor may not be able to handle 4k 240fps 16 bit.
adrian_b 5 hours ago|||
You are right that I have not mentioned this, but indeed wide color gamut monitors should also support 10 bit or better resolution per color component.

Software that does color processing should convert all input pixel formats into BT.2020 linear FP16 color components, do whatever processing is desired and convert from linear FP16 to whatever pixel format is sent directly to the monitor through DisplayPort/HDMI, as the last step.

I have not looked on the market to see how widespread are different kinds of monitor specifications nowadays.

I am using relatively cheap monitors, but not the cheapest, e.g. some common types of Dell monitors. There are more than ten years since my minimal requirements for a monitor have been 4k resolution, 10-bit color components and Display P3 color gamut and 60 Hz at 4k and 10-bit.

So I believe that, especially after a decade, it is easy to satisfy these minimal requirements or better, except that not everybody checks the monitor specifications when they buy one.

Aurornis 3 hours ago||||
> Your monitor may not be able to handle 4k 240fps 16 bit.

10 bits per channel is the common target for higher color depth. The formats with 16 bits per channel are generally for image storage and allowing more bits for downstream transforms to avoid quantization. I don’t even know if there are video cards that would output 16 bits per channel, let alone panels for it.

ComputerGuru 2 hours ago||
I don’t think 16 bpc is supported in the standard consumer workflow but I believe 12 bpc is?
rbanffy 1 hour ago||||
> 4k 240fps

As a cinema enthusiast, I say 24 fps ought to be enough for anyone.

ComputerGuru 2 hours ago|||
These days cheaper monitors with only 8bpc support advertising higher color support use FRC to flicker between different 8-bit colors at a high enough rate to trick the vision receptors to seeing a mix between the two.

Separately, sorry to nitpick, but while wide gamut colors with only eight bits of data have lower resolution than sRGB, that doesn’t make them an inferior option. You might not be able to specify the exact shade but a) your effective accuracy is still greater and b) you trade that for greater range.

Just as an example, assume you have buckets of granularity 1 (sRGB) and 0.5 granularity (wide gamut). With only eight bits you can precisely select any individual bucket of granularity 1, whereas with only eight bits you sometimes miss the intended wide gamut 0.5 precision bucket and hit its neighbor instead (as if you had a granularity of 1 in this specific worst case). That doesn’t make it worse; you just aren’t taking full advantage. On top of that, your range with granularity one is, say, 200 to 800 while your “range” with the wide bucket is 0 to 1000 (just as an example).

There’s a reason photos or graphics saved as eight-bit png or jpeg still manage to look ten times better in a wide gamut profile than in sRGB (on a better-than-sRGB display).

TheAceOfHearts 10 hours ago||
I took up acrylics painting a few years back and I've been surprised by how much is lost in photos and videos. The two colors with which I've noticed this the most are ultramarine blue and prussian blue. I don't think it's just the color though, part of it comes down to how light is reflected off the painting and where you're standing, as well as the texture and the brush strokes. I have a few paintings hanging in my room and occasionally I'll look at them for a while and it'll reveal a new perspective to me that I had previously missed, despite being the one who made it.

This post is making me feel a bit inspired to go outside and immerse myself in the forest to take in the greens. Thanks for sharing.

jakzurr 26 minutes ago|
Thanks mentioning acrylics. Now I'm wondering if new technology will eventually improve our printing to allow better colors in news media, and even in prints in art exhibits?

Does anyone have any comments on the future of printed media?

thadk 17 minutes ago||
Somewhat related, but TIL the macOS Screenshot.app utility (and the system wide keyboard shortcuts) in Sonoma got HDR capability to help re-convey just a bit more fidelity. Even in PNG, it keeps the display profile, just not HDR.

Open Utilities->Screenshot.app Options->Capture/Capture Format->HEIC. Note, it changes the system screenshot default away from PNG too.

Stitch4223 8 hours ago||
The phosphor screen of a B&O MX8000 TV (a Philips tube) was unlike any I’ve ever seen in terms of cyan intensity. That was in 2020 while the tv is from the 1980’s. Playing Donkey Kong on it was totally different than any other screen. It was like a Morpho butterfly, but in the article it is pointed out that phosphor screens have limited color range.

Triangles between screens may differ with tuning, but I suppose they all are limited in range. I’ve yet to experiment if this experience was a “brand experience” because I liked the TV or that the colors are indeed more intense than even some HDR/DV flat screen from the past few years.

This article was so well written that it gives a lot of energy to make this comparison for real. Absolutely masterful writing and all of the plenty examples make me want to look for colors I’ve missed out on while watching so many screens.

What the article does very well is vibrantly describe what you are missing and then post an image of it, such as a beach. Looking at that image, it falls absolutely flat compared to memories and the imagination of those places. This makes it tangible how limited screens really are.

Edit: added last paragraph

strogonoff 6 hours ago||
I’m not sure it’s possible to truthfully describe what we are missing in reality with a photo.

You can publish a photo with default automatic JPEG processing, say by a phone, and it will certainly look flat. You could also present a masterful interpretation of raw sensor data that uses the most out of the available display space, and the impression might be different.

There is no objectively correct way to represent reality in a photo; even the concept of neutral grey is not a real thing as soon as perception is concerned. A default camera interpretation of light is baseline and safe to maximally avoid awkward edge cases. We all know that time we photograph a bright pink sunset but our phone renders it as pale yellow or orange. However, give the same shot human attention, and even though it may never be as pink as what you have perceived in reality it will pop enough that the viewer will have a similar response.

It is photographer’s job to work raw data in specific ways and make what impressed you stand out to your audience, arranging colours both relative to each other and in absolute display space, however limited it is. Human eyes are incredibly adaptive: we lower our relevant thresholds, adjust our idea of neutral grey—in short, we adapt to given display medium, to given photographic style, etc., and in the end perceive a true lush lagoon in a photo even if our eyes only receive a truly minuscule amount of colour range present in the scene.

Giefo6ah 3 hours ago||
The original 1953 NTSC standard specified phosphors with a way bigger gamut than sRGB, that were chosen to approximate the gamut of film projectors.

Original NTSC cyans are more saturated than even DCI-P3 cyans.

Typical CRTs use the cheaper, brighter phosphors specified by SMPTE C (the basis for the sRGB gamut) and a circuit that pumps the saturation to compensate.

It's likely your screen uses the better phosphors instead of a colour correction circuit.

rollulus 8 hours ago||
What I missed in the article: the curves of the three “cone kinds” overlap. What if you could stimulate kinds of cones individually to see entirely new colors? Some people shoot layers at them into eyes. But you can also try this website: https://dynomight.net/colors/ (previously on HN but search fails me).
lefra 6 hours ago||
Last year a research group managed to do just that, see https://www.science.org/doi/10.1126/sciadv.adu1052 for details.
mr_toad 1 hour ago|||
https://en.wikipedia.org/wiki/Tetrachromacy
limbicsystem 8 hours ago||
Through the magic of liner algebra it turns out that you can stimulate cones independently even with normal displays. Search for 'silent substitution'!
ProllyInfamous 3 hours ago||
Also search for "impossible chimerical colors"

<https://en.wikipedia.org/wiki/Impossible_color#Chimerical_co...>

lefra 11 hours ago||
Really nice article, I'll look closer to green lights next time I see one.

The most striking experience I had was working with a blue laser (430nm). The best way I found to describe its color is that it was screaming "blue" at me. Since then, I'm always disappointed when looking at a screen displaying #0000FF.

tomaskafka 10 hours ago||
Sounds like we need the next VR glasses to shine colorful lasers into our eyes instead of screens.
high_priest 9 hours ago|||
"Destroy them with lasers!" https://youtu.be/u6-U-apEUZI
functionmouse 4 hours ago|||
it'll be awesome, once
olejorgenb 10 hours ago||
"This is a good time to spare a thought for our red-green colorblind brethren. [...] it is to them that we owe the beautiful color of green traffic lights. The spectral requirements that make the green signals distinguishable from red in their eyes make them beautiful in ours."
krick 4 hours ago||
Really enjoyed the article, even though it's not a new topic to me, but still it was very interesting, very nicely written and I still managed to pick up a couple of new details.

To be fair to Jurassic Park, though, at least in the book the quirks of T-Rex's vision were explained by the details of genetic engineering (the base DNA used was some kind of amphibian, that allegedly had this problem — still not very scientifically plausible, but not quite as silly as in the movie). It goes a long way to emphasize that in the end these are not real dinosaurs, these are human-made abominations.

ralfd 2 hours ago|
Doesnt Dr Grant scare a kid in the beginning with the Velociraptor and say there that T Rex vision was movement based? I wonder if Chrichton made that up or if it was a real theory by paleaologists?
Yinameah 2 hours ago||
Incredible article. I used to work as a light designer and therefore spent lot of time thinking about colors and training my eyes to see them more precisely. I lost some of this competency surprisingly quickly, but this article brought many great feelings/souvenirs back.

Thanks to the author

fmajid 6 hours ago||
> Today, on your way home, look at the “green” light on a traffic signal. It’s not green.

Independently from this, the names for colors are culturally determined.

The Japanese call green traffic lights as 青 "ao", blue.

Russians have different terms for different shades of blue.

qingcharles 2 hours ago|
This is a good point. Here's the article on the weirdness of blue/green in different cultures:

https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...

olejorgenb 9 hours ago|
Off topic, but the other articles are well made too. I enjoyed this one: https://moultano.wordpress.com/2025/02/24/you-should-make-cr...
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