Get the top HN stories in your inbox every day.
tvst
turnsout
CRTs absolutely DO "ghost." Much like turning off a filament light bulb, the phosphors respond instantly, but there's a long tail where they fade out. In practice, it's not perceptible, just as it's not perceptible in any good LCD or OLED.
There were also a few wrong numbers in this video, such as the idea of a normal CRT refreshing 75 times a second (nope).
And I was expecting some discussion of interlacing, which had a big impact on how pixels and animations appeared on CRTs.
But I agree—it was fun to watch!
toast0
> And I was expecting some discussion of interlacing, which had a big impact on how pixels and animations appeared on CRTs.
Not for 8-bit systems and the vast majority of games on 16-bit systems. AFAIK, all of the 8-bit systems used not-standard video where all frames were odd frames or all frames were even frames, so you got 50/60 Hz progressive video with no interlacing (240p in NTSC, 256p in PAL; both subject to not all systems put meaningful output on all lines). Some 16-bit systems allowed for interlaced modes, but it was rarely used. Fifth generation (N64/PSX/Saturn/etc) made interlacing a lot more common; those systems were more likely to render to a frame buffer and then you can send half the lines in each field and get an increase in vertical detail much easier than getting the same effect working with a sprite engine.
ddingus
The trails can be fun. Playing monochrome bitmap or vector games like ASTEROIDS, in the dark on a CRT with contrast up, brightness down to black, looks and feels, plays amazing!
aimor
"The video makes it seems that there's no temporal bleeding on CRTs. This sounds unlikely to me..."
There is, but I don't remember it being noticeable even on cheap TVs, except in high contrast situation where the screen is dim with bright things moving around. I still miss the lack of motion blur that CRTs gave by default.
I found a forum post where someone lists these values:
"Phosphors in current use for CRT-applications:
Red: phosphor = Y2O2S:Eu3+. Lifetime (1/e time) = 150 us, single exponential.
Green: phosphor = Zn2SiO4:Mn2+. Lifetime (1/e time) = 10-15 ms. Clearly, this is quite long and is the limiting factor in increasing frame-frequency.
Note: the emission decay has a highly non-single-exponential decay --> at long times (~1 s) still some emission can be observed by the eye. This can be seen clearly by looking into the green CRT directly after the image was switched off. However, the intensity is too low to cause problems in an active image when the image-frequency is below ~100 Hz.
Blue: phosphor = ZnS:Ag,Cl. Lifetime (1/e time) = ~100-200 us. Note: not single-exponential decay, but no emission at long times.
(Source: Shionoya & Yen, "Phosphor Handbook", 1998.)"
https://www.avsforum.com/threads/what-is-the-rise-and-fall-t...
And in this high framerate video of a CRT you can see the different colors decay at different rates. Here the blue seems to decay the fastest. But they're all imperceptibly dark by the time the scan line comes around again. I have no idea if there's any cumulative effect that's perceptible.
pierat
With emulation, there's always a deeper level of emulation you can do to approach "perfectness".
In this case, the pinnacle of emulation of a CRT is to simulate photon emission in a tube, and simulate the response curve of each phosphor element.
To do that would probably take a supercomputer to effectively calculate real-time.
According to this paper, there are (1.12 x 10^16) photons per second produced by a 1-lumen source over the interval from 400 to 700 nm . And with a 200 nit CRT is roughly 600 lumen... which is roughly (6.7 x 10^18) photons per second... if you just model them as a particle. To take in quantum effects, yeesh.
https://www.imaging.org/common/uploaded%20files/pdfs/Papers/...
nyanpasu64
Phosphors are funny little things. In my Gateway VX720 (like Diamond Pro 710, not the other VX720), the blue and green phosphors light up the fastest and decay to near-zero the fastest (100-200 us), but have a long dim phosphor trail that persists for hundreds of milliseconds. Red starts up slower and decays slower (hundreds of us), but reaches zero brightness well before the next frame.
OLEDs without strobing, on the other hand, have a full frame of brightness persistence (and LCDs have slow color changes on top of that).
blackguardx
I think the phosphors of CRTs usually had a very low persistence in that the decay time was less than a frame time. If you look at out of sync videos of CRT displays, it looks as if only perhaps 1/8 of the screen is illuminated at one time.
michaelteter
"tiny little light bulbs" - cracked me up.
SV_BubbleTime
He was exactly right for OLED and Plasma though.
loveparade
Very cool! But what's even more interesting to me is the effect of our brain filling in the missing details that are now explicitly rendered in modern games.
I think I felt more immersed in retro games because my brain knew that it's supposed to fill in all these details. With modern games it's close to realistic, but not quite, and my brain doesn't even try to fill in what's missing. It's also more difficult to concentrate on the gameplay when all details are rendered on screen.
I'm also constantly surprised how little graphics matter for an enjoyable experience. A game with amazing graphics blows my mind for 15 minutes. But then I'm used it and I stop caring about visuals altogether, unless they get in my way.
xnorswap
Yes, this effect is fascinating.
I've been playing de_dust2 for 20 years.
And in my mind the quality has always felt essentially the same, through CS, CS:Source, CS:GO and now CS2.
Each was a significant rendering upgrade. And I know I could never go back an iteration, but going forward as it has, the game in my mind's eye is just how CS looks and how it's always looked.
I'm the opposite about "retro" gaming though. Having experienced better fidelity and more readable fonts and better sound, I struggle to play games which don't have that, or worse, deliberately choose bad font rendering as a "retro" effect.
It's why one of my favourite games is Factorio, because it's almost the opposite of retro.
Despite being sprite based, it's the cutting edge of modern sprite rendering. The sprites are generated from 3d renders, and you don't find yourself suddenly in 640x480 or crappy fonts out of some nod to the ages.
somedude895
> It's also more difficult to concentrate on the gameplay when all details are rendered on screen.
I‘ve noticed that as well. I much prefer say Tomb Raider 2 with its clear edges and flat surfaces to the modern ones with all the foliage and clutter and lighting effects. But I put that down to getting old.
semi
this is why I never could get into counterstrike after 1.6
it's not just the visual noise, it's also the inconsistent behavior introduced by those details.
Yes everything being flat boxes was boring looking but I knew exactly what would happen when I tried to shoot through it or bounce a grenade off of it.
Now it's not obvious if that stack of sandbags is actually a single surface and my grenade will bounce off of a gap or if it will go through it. Or if that random bucket I'm shooting at is synced on the server and real or is a local prop.
delecti
> It's also more difficult to concentrate on the gameplay when all details are rendered on screen
This has made me really appreciate art direction over raw fidelity. The first party PS5 games are all beautiful, but Horizon Forbidden West was almost difficult to look at because there's just so much detail everywhere, much of it irrelevant. In contrast God of War Ragnarok is just as beautiful, but the art direction is much better suited for the gameplay, so I never had problems with losing important details in the sea of fidelity. Horizon is like blowing out your taste buds on pure sugar.
magicalhippo
> I think I felt more immersed in retro games because my brain knew that it's supposed to fill in all these details.
I remember having a great time playing Rise of the Triad[1], both single player and against my buddy. I was quite good at the time, and often won against my buddy.
Some years ago I fired it up again, and set it to the 320x200 pixels I used to play with, with pixel doubling to get it to about the size of my then ~13" monitor (can't recall except my later 15" was a decent upgrade).
And I couldn't play at all. Anything beyond about 2 feet was just a mess of random pixels. Felt like I had a severe case of myopia.
Yet I also vividly recalled how teenage me would fire rockets at those two pixels over there, killing my buddy...
anthk
Get a libre ROTT engine (DDG/Google) it and use the datafiles with the engine. Then you can set the resolution to something much better.
michaelteter
> the effect of our brain filling in the missing details
Why books are often better than their movies.
anthk
And proper roguelikes (Hack/Nethack/Moria) and text adventures. Also, the CRT blended the pixels, so Max Payne with the CRT color contrast looked almost real life. Nowadays, not so much. LCD screens look dull.
tomxor
Shameless plug, animation trying to illustrate a Trinitron aperture grille scanline effect in 140 js chars:
https://www.dwitter.net/d/12335
Although like the author I feel like the Trinitrons don't look so good. Although this is entirely subjective, I'm pretty sure I grew up on playing games on a "crappy" old shadow mask TV where the colours seem to bleed together better because of the subpixel arrangement that I think makes it blend on the Y axis as well as the X axis.
[edit]
Hah, found my old TV/monitor: https://www.youtube.com/watch?v=M7S_WLrvHW8 Can't figure out if it's a shadow mask or not though.
keyle
That's cool!
winstonrc
I wrote a brief article discussing my thoughts on playing 240p games on a CRT compared to a modern display[0]. It’s hard to perfectly convey, but the picture really does look exceptional and so much better than on a modern display and is something worth seeing in person.
The MiSTer FPGA does an excellent job with filters to recreate that experience but isn’t 100% there yet. The Analogue Pocket also does a great job recreating the look of GB, GBC, and GBA games. I’m very impressed by the people that have developed these filters and am optimistic about their implementation in the future. I’m not always going to have a CRT, so filters are the next best thing to capturing the original look.
[0] https://www.winstoncooke.com/blog/2023-08-26-appreciating-24...
eternityforest
Is anyone making physical lenses to go over an LCD? Old CRTs were convex instead of flat, which is almost more noteworthy than the look of the actual pixels, especially in up close in an arcade machine.
winstonrc
Exactly. The convex display allows for an impression of the intended image whereas a flat LCD is more of a “soulless” pixel-by-pixel translation of the visual data. A flat display will inherently always be off due to this.
pipes
Retro arch does a good with filters too, especially the mega bezel ones. Though I mostly use my mister these days. Both on the same Samsung quantum dot oled. Street fighter 2 looks amazing on both.
paldepind2
Thanks for sharing. Those photos of Samus give a very good impression of the difference. The CRT one is clearly better.
winstonrc
It looks so much better in person too! I had a difficult time accurately capturing the CRT screen with an iPhone. Perhaps I could borrow a DSLR with a tripod to take a better photo one of these days.
PostOnce
High-DPI OLEDs and CRT shaders are the answer for preservation, I think. Shaders can cover a hell of a lot of the nuance. Phosphor persistence (fade-out time?), light bleeding over into the next uh... thingie. We have the technology :)
the shaders may not be perfect yet, but it makes me happy that we have the option.
MenhirMike
The nice thing about High DPI is that you can re-create the aperture grille/shadow mask of a real TV to get the actual sub-pixel pattern. That requires a high resolution since you need both enough pixels (since every original "pixel" requires 4+ pixels now) and small enough pixels (to make the effect not overly exaggerated - unless you want to emulate a low end TV with gigantic dot pitch). Also, no more "fake" scanlines because the entire mask is fake :)
Also, issues with pixel aspect ratio (8:7 vs 5:4 vs 4:3, square vs rectangular pixels) can be resolved while still being able to scale by exact integers rather than floats.
It's funny, but 4K displays might really be one of the best ways to play retro games nowadays, I'm hoping that upscalers (like the Retrotink 4K, or maybe future OSSC upgrades) will bring some of the stuff we've been doing in emulators to real hardware as well (though yes, that thing will cost several hundreds of dollars, so emulation is probably going to stay the preferred option for many).
Now we just have to solve losing the sync signal for games that switch between 240p and 480i during gameplay, or that don't have an exact 60 Hz refresh rate - Variable Refresh Rate displays are actually a real opportunity here as well. Oh, and find a way to all of that without introducing any display processing latency.
rob74
So it takes a 14" 4:3 4k resolution OLED display (does such a thing even exist?) and a top-of-the-line GPU to emulate a 30+ year old 14" CRT monitor?
MenhirMike
And even then it's probably still not perfect since you're sending to a framebuffer instead of controlling the beam directly, which adds at minimum 1 frame of latency. (Unless there is a "real-time" way to send a picture over HDMI)
idonotknowwhy
And it still won't work with light gun games, and the motion clarity isn't the yet.
zozbot234
High-DPI OLED can do even better than the analog effect of CRT's. The latter is basically like a Gaussian blur (which is the best you can do in the purely analog domain!) but a high-DPI screen can use Lanczos upscaling for a much sharper effect, somewhat reminiscent of the look of oil or water-color paintings. There are also pixel-art specific upscaling algorithms that preserve the limited color palette of old retrogames while still smoothing out lines and curves.
rob74
I'm afraid you're missing the point here - people don't want "even better" than CRTs (otherwise they might as well go and play the latest 3D shooter on their 4K display), they want something which gets as close as possible to how a real CRT looked like.
Yeul
I wonder if these people watch Blade Runner on videocassette or if they opt for the blueray release.
PostOnce
I lose it when I go to an arcade and they have some bootleg emulator running with one of those hideous blurry upscaling filters turned on.
It's like George Lucas and his Original Vision problem... it's not good to mess with existing art people already love
thfuran
>water-color paintings
That's not really a medium known for its sharp edges and fine details.
watercolorblind
Yeah, it's a medium that is not known for fine details given everyone's experience with it in school growing up, and the landscape/flower paintings that are common at art festivals; however, that does not mean that is all that can be done with the medium. Some artists pursue photo-realism [1].
Using something like a heavier weight (takes more layers), hot press (smoother grain) watercolor that makes it easier to add finer sharper, details. Additionally, there are mixing mediums [2] that allow changing application in different ways and there is masking fluid which helps preserve a sharp edge when working on multiple layers.
There is a variety of media that is "watercolor" as well: watercolor pencils, water soluble pastels, opaque watercolors, watercolor markers, and granulating watercolors.
1: https://doodlewash.com/guest-artist-photorealism-watercolors... 2: https://www.art-is-fun.com/watercolor-mediums
zozbot234
Yes, the point is that given any level of detail the water-color picture is a lot sharper than the Gaussian-blur equivalent, which is like putting a pane of frosted glass over the picture.
ralferoo
Maybe not, but if you were to compare a low-resolution scan and a high-resolution scan of the painting, you'd easily see the difference.
dcow
I have a 120hz OLED. Where can I check this out?
bluescrn
High DPI screens give more options for exact integer scaling too, before putting shaders over the top.
The other often-forgotten issue is running 50Hz PAL games smoothly. This should be getting easier, with more screens able to run at 100Hz, but it's rare to see an emulator actually support this.
Would be nice if modern 4:3 panels were available, too (And not just for retro gaming, they were more practical than 16:9 for work PCs)
willis936
I think we are still several years away from flat panels being able to sinulate phosphor persistence and the strobed nature of CRTs. CRT phosphors decay with a time constant of 1-2 ms, so you'd want at least 1000 Hz to properly simulate it. Even if you couldn't get that fast you could at least get the meat of it with backlight strobing that has ~25% duty cycle. This gives incredible motion clarity but it is very rare on modern displays. I don't really know why. Display manufacturers should be giving users the option to reduce brightness by 75% for motion clarity if they want it. It will also be a while yet before modern displays can hit the product of motion clarity and brightness that CRTs have hit since before we were born.
zozbot234
> with backlight strobing that has ~25% duty cycle.
Yes, that's what happens when you set screen brightness to the lowest setting. And guess what, it looks terrible.
willis936
Similar, but not exactly. The details matter. The strobing needs to be synchronous with the frames.
Adding flicker without the motion clarity benefit looks bad. Strobing in sync with content looks amazing. How many people complained about 60 Hz flicker on CRTs over their 70 year reign?
WithinReason
In addition, high DPI/refresh screens can recreate any CRT you have a shader for, or only recreate the "artistically relevant" aspect, the blur and gamma characteristics and not recreate the irrelevant flaws of CRTs.
dbttdft
After researching this I believe the main je ne sais quoi of old console games on CRT in order of importance is vsync, lack of motion blur due to CRT, low black level (and thus high contrast that LCD cannot begin to compare to), and then phosphor layout.
>LCD is comprised of tiny light bulbs: LEDs
No, it's comprised of liquid crystal (LC) units, each of which effectively control how much of the backlight (which may be LCD or CCFL) passes through itself and thus how bright that pixel is. Although I can see why you would think this with the introduction of "LED Monitors" around 2010, which is totally not intentional misrepresentation from the marketers.
>This is way slower than a CRT
LEDs are fast but LCs are indeed slow.
>Even if you could turn it on and off really fast there's a little bit of a fade that's what they call grey to grey
Smearing is not noticable in LCDs made after the early 2000s. There is still motion blue but that's due to no black frame insertion.
>Some pixels in the LCD if they are a similar color will not even change
This is not a known thing, it's made up. That would require storing a frame and anaylzing it against the previous frame although I wouldn't put that above them (and they do this for other reasons once in a while). This sounds like a corruption of spatial/temporal dithering which actually is a thing in most or at least half of LCDs.
>It doesn't draw the entire thing at once like on an LCD
LCDs don't draw all at once, they scan out just like CRTs (some draw all at once but it's pointless and adds (some) input lag).
>The camera is 30 fps and the tv is 30 fps and somehow you see the band go across the screen
It's because the camera has to be synchronized with the TV and have the exposure set up a certain way otherwise it will capture the screen, e.g., half way through the scanout of a frame. Although I'm not sure you can find any CRT or LCD that can go down to 30Hz.
rwmj
This channel has a bunch of videos about how CRTs handle retro video games: https://www.youtube.com/@mylifeingaming
Unfortunately youtube seems to have broken the ability to search only within a channel, so I can't find the exact one I'm thinking about.
Edit: This one: https://www.youtube.com/watch?v=RAi8AVj9GV8
Dwedit
This video is making so many mistakes. From claiming that LCDs use "a separate light bulb for each pixel" to claiming that retro games "run at 30FPS".
zokier
Of course this is well-known in retrogaming/emulation community, which is why there is a wealth of really good CRT shaders out there
washadjeffmad
You're right that this has been a goal since console emulation arose over two decades ago. There's been a lot of bad sprite art spawned over the past 20 years by people who've only ever used LCDs who thought they were recreating something "retro".
Only recently has anything really crossed a threshold of reproduction in software that looks and feels like using a CRT on certain types of displays.
Kiro
I prefer the "bad sprite art".
offices
It reminds me of how 'we' like statues made to look like Roman statues - after the paint has faded.
sen_armstrong
Sharp pixels have always been around too. Even in 1982 there was the pc-98's 640x400 crt monitor that would clearly render dithers -- which its games still chose to use all over, even when they got 16 colors. An lcd doesn't do much worse, and in fact those city nightscapes with pinpoint stars and lights look fantastic on modern displays.
ekianjo
Crt shaders cant really replicate what CRTs actually look like.
Tade0
To me this is sounds like the tube vs solid state amplifier in guitars debate again.
I think the question should really be: can they do a good enough job?
My take is that with the right display they can.
CRTs didn't have an impossible refresh rate, colour gamut, contrast or resolution - arguably they kind of suck in each of these areas compared to modern displays.
I mean, we didn't see screens show deep teals until OLED arrived.
willis936
It's a similar argument, but as with all engineering questions the details matter. The human auditory system can be entirely fooled with 2 channels of 40 kSamp/s 16-bit data: 1.3E6 bits per second. The human visual system is much more difficult. It's hard to put a hard number on it due to the stochastic nature of "pixel" sampling in the eye, but generally 1000 Hz is accepted [1] (pulled from blurbusters). I'm also going to gloss over foveated rendering since I'm assuming a one-way "trick the system" box. The human visual system would need 2 channels of 7500 x 7500 (120 degree / 0.016 degrees per pixel) x 1000 Hz x 3x16-bit color: 2.7E12 bits per second.
To get to my point: it is technologically trivial to work with audio compared to video. Audio simulation and reconstruction has been a mostly dead area of research for decades while video is still flourishing. Audio did not stop at the actual technical best place it could have, but when it was good enough and diminishing returns hit.
1. https://www.lrc.rpi.edu/programs/solidstate/assist/pdf/AR-Fl...
undefined
giantrobot
They most certainly can but the requirements are steep. Being able to run at 4K/120Hz is where you start to get very accurate simulation of a CRT. You need a high resolution to draw the phosphors, mask, and bloom. You need the high refresh rate to be able to have realistic phosphor draw and decay.
bluescrn
Playing on an original Asteroids cabinet with vector monitor these days is an interesting experience. I was surprised by the brightness/dynamic range, it seemed way beyond what you get from an LCD. Its like it's got an bloom effect on the brightly-glowing bullets.
Jensson
Yes they can, I saw them in the video we are discussing, my screen showed me smooth pixels instead of blocky ones even though I don't have a CRT screen. Of course it isn't perfect, since my screens doesn't have infinite resolution, but it is good enough. Nothing stops a filter from getting the exact same result as taking a picture of a CRT screen.
ekianjo
It cant replicate what CRTs look like because how the light is emitted from a CRT looks nothing like how the light is emitted from a LCD. No matter how many shaders you use, you cant change any of that.
musha68k
They fundamentally don’t but a high quality / high refresh OLED display can come very close and if implementation done right IMHO can even surpass experience in some cases. I still play old games on my old beloved tubes but to be frank often just for purity / nostalgic reasons and because I like the original 4:3 format without (“perfect black” even) overhead on the sides. I hope Apple will finally Switch to OLED for their iPads as the aftermarket / replace displays for those usually are well affordable and usable for e.g. a wall mounted “cabinet”.
bni
With HDR and OLED I think its very close
idonotknowwhy
They can for static images. They've even got bloom (white scan lines are thicker), simulated convergence and geometry defects, etc.
But they can't match the motion clarity of a CRT.
My 240hz oled is not as clear as a 120hz or even 60 hz CRT when I put them side by side
PostOnce
Why not, specifically?
parski
The most crucial difference (in my opinion) between sample-and-hold displays and a CRT is the motion resolution. Motion just looks so much better on a CRT. Lately this has been remedied with features like black frame insertion, high refresh rates and technologies like ULMB 2. Also, using HDR on capable displays we can replicate the glow of the phosphor with much greater accuracy. I can't wait to get my hands on the RetroTink 4K and play around with BFI and HDR along with the filters after the perfect upscale to 2160p.
TacticalCoder
Emulation for preservation is a bit weird but why not. Now... CRTs are still built and sold today and you can also buy brand new CRT controller boards from China. Not "new old stock" but brand new stuff, still built today.
For anyone who has the room for it, just go buy an actual arcade cab with a CRT in it. Then put a Raspberry Pi with a "Pi2JAMMA" (not affiliated with these guys, but I like it) connector in it. You'll have thousands of games and it's basically the real thing (short of very specific cases like the game Tempest that was directly controlling the electron beam).
I'm a happy camper with one vintage arcade cab, which I own since years. A friend of mine saw it and went berzerk: he now has six arcade cabs.
If I wanted to be facetious I'd say it's arguably less work to buy a vintage arcade cab with an actual CRT and put a RPi + Pi2JAMMA adapter in it then try to get a shader working on a modern screen.
If you want the real arcade feeling you need proper arcade joysticks anyway: at that point we're probably already talking about a cab (you could have just the joysticks controller, but it's not as good as the joystick in an arcade cab).
So if you've got a cab, you may as well go with a real one (with a CRT that is) and an adapter that'll drive the CRT (like the Pi2JAMMA one).
As a bonus you'll also be able to put real vintage PCBs in your cab.
eropple
> CRTs are still built and sold today and you can also buy brand new CRT controller boards from China. Not "new old stock" but brand new stuff, still built today.
Have any recommendations? Buying a PVM is a bit outside my price range.
aastronaut
There was one in an article on hackaday[0], also featured here[1].
[0]: https://hackaday.com/2023/08/16/new-motherboard-improves-old...
fomine3
Is there a new CRT itself?
Jeema101
I was at a retro barcade not too long ago and came across an old Centipede machine.
Maybe this machine just had a really good CRT in it, but the level of intense brightness against the pitch black background was honestly sort of mesmerizing. I had forgotten just how good CRTs were in that regard.
(A little bit off-topic from what the guy in the video is discussing, but I thought it's worth mentioning since it could be another reason why people have such fond memories of CRT gaming.)
Get the top HN stories in your inbox every day.
Great video, except for a few wrong details that really get to me...
- The pixels in an LCD aren't little light bulbs. They are little lamp shades. (The pixels in an OLED display are little light bulbs though)
- A CRT doesn't shoot light. It shoots electrons.
- The video makes it seem like pixels in an LCD update all at once. Not true! They're scanned.
- The video makes it seems that there's no temporal bleeding on CRTs. This sounds unlikely to me...
- The main difference in image quality between coaxial and composite inputs is not that coaxial needs to stuff audio and video together. It's that in coaxial the signal is shifted to a carrier frequency as if it came from an antenna (usually channel 3 or 4) so the decoder needs to bring it down to the frequency it uses internally (called the intermediate frequency) before sending it to the screen. This degrades the signal.