EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: oldnewb on May 02, 2017, 07:12:18 am
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Was it merely convention (e.g., users expected it), or was there a technical consideration? Surprisingly, Google was not forthcoming with an answer. I could hazard a few guesses but figured I'd ask first.
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VHF TV? I don't think the UK ever used it along side UHF. When it was monochrome, TV was all VHF, then it was dropped and replaced with UHF, when we moved to colour.
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Errrr no. The UK switchover took 15 years, so there was a long period in which dual standard 405 line (VHF) and 625 line (UHF) sets were popular. See https://en.wikipedia.org/wiki/405-line_television_system (https://en.wikipedia.org/wiki/405-line_television_system)
The use of two selector knobs for VHF and UHF was because of turret tuners that mechanically rotated a pre-tuned frequency selector card into position to connect to the active parts of the tuner circuit to select each channel. It was technically possible to build a combo turret tuner which used different contact positions for VHF and UHF so either a VHF or UHF channel selector card could be fitted in any turret drum position, but the result was notably bulky. Separate turret tuners, with the UHF one selected by a dummy position on the VHF one (as there was never going to be a need for more VHF channels), that also switched the line timebase from 405 to 625 lines/frame, was cheaper, typically lower noise, and allowed manufacturers an easy factory fitted upgrade path for their existing set designs.
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The youth of today! ::) ;D
I remember our family's Philips TV set of the time. It was pretty featured for the time:
- LDR automatic brightness compensation.
- Automatic channel change... A push button which caused a little shaded pole induction motor to engage (starter motor style) to rotate the VHF turret tuner to the next populated slot (kerchunk, kerchunk, kerchunk).
- A big chunky slide switch at the bottom of the panel which switched over to the UHF tuner (simple knob and tuning scale). That was only used to watch BBC2 - the first channel to be launched on UHF, everything else was initially still on VHF initially.
These sets required quite a bit more complexity in the scanning circuits, VHF being 405 line and UHF being 625 line.
There was also a socket for a (plug in) remote control. I eventually found one in Lisle street - it had analogue thumbwheel knobs for volume, brightness and contrast, together with a channel change (kerchunk...). It had no facility for VHF / UHF switching (the slide switch on the TV was switching IF and scan ciircuitry). I also remember that the remote control cable was about the thickness of a 13A mains lead, just a bit stiffer! :D
P.S. Not forgetting that you also had to get a UHF aerial installed to plug into the second aerial socket!
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Was it merely convention (e.g., users expected it), or was there a technical consideration? Surprisingly, Google was not forthcoming with an answer. I could hazard a few guesses but figured I'd ask first.
Simple: There was a time when there were two different types of TV signals being broadcast.
One tuner circuit in your TV wasn't enough.
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These sets required quite a bit more complexity in the scanning circuits, VHF being 405 line and UHF being 625 line.
"Fog in Channel - Continent cut off" :-DD
The 405 line VHF system was a pure British thing (probably also included the colonies).
Everywhere else it was 525/625 line systems (Russia excepted).
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Here in North America, having 12 channels on the 2 VHF sets 2-6, then 7-13, it was easy to make a knob which rotated and stopped in 12 slots after 1 revolution, on 2 separate bands. VLF was channels 2 through 6 (approx 54Mhz-88Mhz), VHF was 7 through 13(approx 174Mhz-216Mhz). These channel knobs had to change tuner calibrations, or had fixed tuned switched capacitors for each channel depending on design.
But, for UHF, the same 525 line video system, going from channel 14 through 83, that's 70 channels (approx 470Mhz through 890Mhz). It was much simpler to just have a 1 turn varicap, or volume control driving a tuning diode, to tune through 75 channels. At times, the tuning knob had dentin steps, but this was nothing more than a a fine tooth gear with a spring bearing ball faking the approximate channel position. Also considering the frequency difference between the VHF and UHF, at the time, sometimes a separate tuner was used.
https://en.wikipedia.org/wiki/North_American_television_frequencies
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It was technically possible to build a combo turret tuner which used different contact positions for VHF and UHF so either a VHF or UHF channel selector card could be fitted in any turret drum position, but the result was notably bulky. Separate turret tuners, with the UHF one selected by a dummy position on the VHF one (as there was never going to be a need for more VHF channels), that also switched the line timebase from 405 to 625 lines/frame, was cheaper, typically lower noise, and allowed manufacturers an easy factory fitted upgrade path for their existing set designs.
Turret tuners... :scared:
*weeps quietly in corner*
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VHF TV? I don't think the UK ever used it along side UHF. When it was monochrome, TV was all VHF, then it was dropped and replaced with UHF, when we moved to colour.
UK TV used VHF for 405 line TV, and UHF for 625 line TV.
When BBC2 launched (about 1963), BBC1 and ITV were still 405 line stations on VHF frequencies. BBC2 launched as 625 line monochrome, on UHF channels. After a couple of years BBC2 went colour. A couple of years after that (1967) BBC1 and ITV launched 625 line colour services on UHF channels, in parallel with their 405 line monochrome transmissions. In 1969 Thorn and Philips launched the first all semiconductor colour TVs that got the cost down, and the reliability and picture quality up, to the point where sales (or more often rentals) started to take off. Those sets no longer had any need to support 405 line modes, or VHF channels, and were pure 625 line UHF designs.
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generally speaking there was only ever limited bandwidth in the VHF spectrum, so the UHF system was a no brainer to allow more licences to be granted for extra TV channels in many countries.
The Zenith TV company was probably the leaders in single tuning knob tuners, with a very smart replaceable tuning strip design tuning unit....that allowed the set to only have a single knob.....very very smart design having an upgrade path for existing sets.
Unlike today with digital channels, back then there were spectrum limits to the amount of analogue channels that could be fit into a local regions bandwidth limits, so the tuners capacity was never really a problem, but only one company seemed to see the sense in the approach Zenith took.....the rest just seemed to cheap out by just adding an extra tuner....rather that working on a solution, or paying patent rights on the Zenith system.
Here is a great video on Zenith thats worth a watch on what happened back in the day....
https://www.youtube.com/watch?v=7lu5jqXaHRE (https://www.youtube.com/watch?v=7lu5jqXaHRE)
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A lot of (all?) UHF dials were continuous tuned (i.e., the knob turned a variable capacitor and/or inductor), and had notches just for convenience -- it was pure coincidence that the notches lined up with real channels, but most of the time it was pretty close anyway, and a little fine adjustment (the fine adjust covered about a channel's span, so you could always hit a channel even if you got "unlucky") would get you there.
I also remember having a B&W TV that had a UHF dial out to ~80. UHF was redefined in the 80s to have 70 channels, and the rest was reallocated for cellphone use -- the earliest analog cell phones. You could see dot and line patterns, and hear sizzling or buzzing, or sometimes garbled voice, up there... ;D
The same tuning mechanism wasn't suitable for the wide frequency span of VHF channels -- in particular, VHF isn't a single band, but is several, separated by gaps. It made more sense to use presets -- the turret tuners mentioned above.
You would also have separate antenna inputs, for similar reasons. Also, I don't think wideband antennas (anything that would be flat, as in, within 20dB kind of flat) ever caught on, probably because of material and manufacture expense, and bulk. So they were always adjustable in some way. Or people just used coat hangers, which honestly will do just as well after some lucky adjustments to a given channel.
When digital tuners took over, a PLL handled all the frequency control with exact precision, and all that was needed was a tuner with a wide range, a high 1st IF to match, and a bit of brain to set the control voltage. TV tuners make an excellent starting point for a quite reasonable spectrum analyzer. ;)
Tim
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The VHF tuner and UHF tuner were separate circuits in the vacuum-tube TV era. The UHF tuner output went to the VHF tuner, and had a separate local oscillator (UHF triode).
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These sets required quite a bit more complexity in the scanning circuits, VHF being 405 line and UHF being 625 line.
"Fog in Channel - Continent cut off" :-DD
The 405 line VHF system was a pure British thing (probably also included the colonies).
Everywhere else it was 525/625 line systems (Russia excepted).
Ha, I've got one word for you - SECAM, go and laugh at the French, they're on your continent! :P
Anyway, who invented television? ;D
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Sorry, Chris, but SECAM is also 625 lines. :horse:
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Yes, but it's a 'pure French thing'. :D
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Sorry, Chris, but SECAM is also 625 lines. :horse:
Sometimes it was 625 lines. Sometimes it was 819 lines.
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Yes, but it's a 'pure French thing'. :D
Actually, SECAM was used in other countries, such as the USSR.
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Actually, SECAM was used in other countries, such as the USSR
Ok, You're right. I surrender. :D
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With or without cheese & monkeys?
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- Original broadcast TV was VHF only
- The UHF (470-894 MHz) band is widely separated from the VHF bands (54-216 MHz) combining tuning function was impractical
- When UHF was rolled out, it was a simply "added" to VHF receivers as an additional, separate module.
- For decades, VHF tuning was accomplished with a "turret" contraption with a separate strip of L & C components for each channel
- Digital synthesis technology was too expensive/fiddly to use for consumer TV receivers in that era
- But varactor-tuned LO (local oscillator) technology had become ready for mass-market TV receivers
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Yes, but it's a 'pure French thing'. :D
Actually, SECAM was used in other countries, such as the USSR.
And wonderful SECAM decoders were made by Soviet engineers to adapt American RCA NTSC color TV designs to SECAM. I had "Rubin" ("Ruby" in English) color TV (mod of some RCA chassis bought/reverse-engineered by USSR) that had two (sic) additional knobs for regulating colour balance and even with them we got Never Twice Same Color reproduction quality in Europe:) On that particular TV with tongue at a right angle I managed to do only two settings - nearly pure green or LSD trip video style.
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I don't think UHF ever really caught on in the US, I don't recall ever having any UHF channels in my area. Back before we had cable and relied on an antenna outside there were just a handful of VHF channels. I remember we got 4, 5, 7, 9, 11 and 13 at our house growing up. That was it for TV, if you wanted to watch something else you could rent a VHS tape.
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In my youth, UHF channels were found in major cities (such as Chicago) where they ran out of space in the limited VHF band. Note that adjacent channels (e.g., 3 and 4) were not assigned in a given market due to interference. Tuning UHF on the old tuners was a pain, but with the shorter distances required in cities the system worked. One Chicago TV personality always wanted to move to a "single-digit station", but only moved from 32 to 20 as station managements changed.
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I don't think UHF ever really caught on in the US, I don't recall ever having any UHF channels in my area. Back before we had cable and relied on an antenna outside there were just a handful of VHF channels. I remember we got 4, 5, 7, 9, 11 and 13 at our house growing up. That was it for TV, if you wanted to watch something else you could rent a VHS tape.
That is probably the perception of people who lived in the top 50 markets in the USA. But it was very different out smaller cities and rural areas.
Of course, now ALL broadcast TV stations (even the ones called "2" thru "13") are on UHF. The VHF band was removed from TV broadcast service starting in 2009. And then broadcasters on channels > UHF 36 were forced to move again by the "reverse-auction" last year. All of the former VHF TV bands and most of the UHF TV bands have been taken away from television and sold off to mobile operators.
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Perhaps it was an urban thing, that could explain why I never encountered it. With the exception of downtown Seattle this whole area was mostly rural communities back then. As late as the early 90s there was still a field with cows in it in downdown Woodinville. Liked it better that way, but that's beside the point.
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I don't think I have seen any TV made after the early 70s that still used separate VHF and UHF channel knobs (except on TV in US shows). The the ones I know all had a bank of channel selector switches with a small range switch and a tuning dial attached.
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Yes, but it's a 'pure French thing'. :D
Actually, SECAM was used in other countries, such as the USSR.
SECAM was devised by the French and then adopted by the USSR for pretty much the same reason: It was incompatible with PAL and discouraged citizens from "Republikflucht via Fernsehen", or "defection via television". Of course, since the underlying monochrome TV format was the same, that didn't do much to prevent people across the border from watching in black & white.
There were apparently no broadcast SECAM cameras, video switchers, VTRs, etc. Everything was produced in PAL, and then trans-coded to SECAM for broadcast transmission. There were some kludges (MESECAM) developed to allow consumer recording SECAM on PAL VCRs, etc.
But then PAL, SECAM and NTSC are all obsolete now in the digital age anyway. :-//
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I don't think I have seen any TV made after the early 70s that still used separate VHF and UHF channel knobs (except on TV in US shows). The the ones I know all had a bank of channel selector switches with a small range switch and a tuning dial attached.
They were common in North America up until the early-mid 80s when digital tuning became widespread. Until near the end of the analog era when globalization had really gone into full swing US and UK TV designs were significantly different.
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The youth of today! ::) ;D
Tell me about it. My daughter was recently reading something when she looked up and said, "So that's why people say 'Don't touch that dial!'"
Kids.
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The youth of today! ::) ;D
Tell me about it. My daughter was recently reading something when she looked up and said, "So that's why people say 'Don't touch that dial!'"
Kids.
I (who grew up in the 1950s with dial phones) recently punk'd a 20-something by asking "What is a DIAL phone?" She proceeded to tell me in detail what it looked like and how it worked until she realized, halfway-through" that I had tricked her. :-DD
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The VHF tuner and UHF tuner were separate circuits in the vacuum-tube TV era. The UHF tuner output went to the VHF tuner, and had a separate local oscillator (UHF triode).
Not all manufactures went down that path......watch the above video.
Some were smart enough to realise there was no possible way customers would populate all of the available TV channels available in the UHF band in one region, so used a limited number of upgrade cards in the existing tuner assembly........it was really a no brainer and it amazes me to this day everyone didn't do the same thing as Zenith did.
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Thanks to everybody that replied. I wasn't expecting it to be such a popular topic! Reminiscing about the "good" old days is fun.
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Of course, now ALL broadcast TV stations (even the ones called "2" thru "13") are on UHF.
Nope, several markets still have stations transmitting on VHF. Here in Chicago the CBS affiliate (which was originally VHF Ch 2) is on VHF channel 12.
Not sure if the 'Lo VHF' part of the band was completely vacated nationwide, but for sure there are many stations still alive on 'Hi VHF'.
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...And does anyone remember the old joke acronym for SECAM?
"System Everywhere Contrary to American Method"
:-DD
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And NTSC was "never the same color twice", an inaccurate rendering of the abbreviation.
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And NTSC was "never the same color twice", an inaccurate rendering of the abbreviation.
Never Twice Same Colour I heard it as.
PAL and SECAM worked really well, MAC and D2MAC were also really nice standards, did they make it over to the US?
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And NTSC was "never the same color twice", an inaccurate rendering of the abbreviation.
Never Twice Same Colour I heard it as.
PAL and SECAM worked really well, MAC and D2MAC were also really nice standards, did they make it over to the US?
I thought NTSC was just 'Never The Same Colour'. The 'Twice' is new to me.
I guess the acronym differs slightly from place to place...
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I previously worked at a university medical school where we had a couple of laboratories fitted out with 30 color monitors each. These were for the med students to watch live video from the anatomy dissection of some small part of the anatomy (hand, etc.) or to view the microscope image in histology lab (the microscopic study of cells and tissue). We had a couple of Norelco/Philips PCB-701 cameras with 3 plumbicons (Red, Green, Blue) and a special optical apparatus to couple the camera to the microscope.
(http://www.tvcameramuseum.org/philips/ldk33/ldk33-150.jpg)
Since we were on a strict budget, we couldn't afford expensive color monitors back in the mid 1970s, so we used Sony Trinitron aperture-grille CRT consumer TV receivers which were "jeeped" with an opto-isolated composite video input. (Opto-isolated because like most consumer TV receivers, they were "hot-chassis" with no power transformer.)
So, after taking an hour to "dial in" the camera (referenced here: https://www.eevblog.com/forum/chat/things-you-hope-you-don't-hear/msg1185122/#msg1185122 (https://www.eevblog.com/forum/chat/things-you-hope-you-don't-hear/msg1185122/#msg1185122)) and then coupling it to the microscope and trying to color balance to the (oddball) color temperature of the microscope illumination, I had to go around to all the TV screens in the lab and try to dial them in to the exact color to match what you see in the microscope. The histology professors were very picky about the exact shade of blue-magenta-purple-pink-red which most of their slides used (from the biological stains they use to reveal cell structure). I was forever going around from screen to screen with the professor saying "no, that is too pinkish" or "no that is too blueish". For all I know the tradition caries on to this day with LCD screens.
So, to me, NTSC meant "No Two the Same Color".
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Even if you were using RGB without having to deal with the NTSC encoding it's almost impossible to get a perfect color balance when you're dealing with an odd color temperature for the illumination and the limitations of the phosphors used in the CRTs. On top of that it's really tricky to eyeball it because the brain is remarkably good at deciding something is "white" and then adjusting everything accordingly.
NTSC was not as terrible as its reputation implies though. I'm sure it was a pain back in the days of vacuum tube consumer TV sets with drifty components and dynamic convergence but by the late 80s when digitally controlled sets were the norm the color was pretty darn stable and consistent.
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Of course, now ALL broadcast TV stations (even the ones called "2" thru "13") are on UHF.
Nope, several markets still have stations transmitting on VHF. Here in Chicago the CBS affiliate (which was originally VHF Ch 2) is on VHF channel 12.
Not sure if the 'Lo VHF' part of the band was completely vacated nationwide, but for sure there are many stations still alive on 'Hi VHF'.
Yes, there are apparently still many (but < 100?) broadcast TV stations still on hi-VHF (physical channels 7-13). I wasn't even watching terrestrial broadcast TV back during the great switch-over. For whatever reason, the three hi-VHF stations here in Portland market went back to their original channels (8 KGW NBC, 10 KOPB PBS, 12 KPTV Fox) although broadcasting ATSC digital now. While all the lo-VHF stations were forced to move to UHF, they retained their original "display channel" for legacy/marketing reasons.
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Even if you were using RGB without having to deal with the NTSC encoding it's almost impossible to get a perfect color balance when you're dealing with an odd color temperature for the illumination and the limitations of the phosphors used in the CRTs. On top of that it's really tricky to eyeball it because the brain is remarkably good at deciding something is "white" and then adjusting everything accordingly.
Dr Land showed a few decades ago that the human visual system tends to find something in the field of view and use it to "color-correct" the white balance. He had some interesting experiments with "Mondrians" (assemblies of rectangles of different colors) under different lighting to evaluate this concept by producing errors in perception.
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Dr Land showed a few decades ago that the human visual system tends to find something in the field of view and use it to "color-correct" the white balance. He had some interesting experiments with "Mondrians" (assemblies of rectangles of different colors) under different lighting to evaluate this concept by producing errors in perception.
I saw an absolutely fascinating documentary about his work a few years ago, I'd almost forgotten about that. The most shocking demonstration was displaying two projected images, one from a B&W slide and another from a single filtered color, I think it was red. When the two were overlaid together it appeared as a full color image. That's some crazy stuff.
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I have seen that or similar.
In my ISF classes, we were shown all that stuff. I knew most, but the 2 color B&W looking like full color was fascinating.
You NEED test equipment, the eye/brain is just an afc/agc/acc mess.
Example: I got a new lens in my left eye to replace a cataract one. A week before, my barber had told me what to expect.
He said compare the colors of the american flag to the Confederate. I guess the Confederate was less saturated.
Anyway I got the operation and the color between my two eyes was astounding.
I wanted to paint a record my experience using computer graphics, but within days, my brain made both my eyes the same in color again.
The new eye had more contrast ratio, pure whites, saturated colors.
The old right eye if holding a hand across either, would show almost exactly what a yellowed old monitor or apple mac looks like compared to a white sheet in the old left eye. I was going to do a gimp of a picture to show people.
But brain made both look the same again 2 days, never had the time to 'paint' a comparison.
Is why I use calibrated test equipment for any commercial video work, never by eye.
Maybe I'll do the right eye, but I am crippled for electronic work because of in my experience, was not prompted in selection of lens implant focus.
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Color is tough to get truly right. Only my studio 'Color Grading Grade' RGB computer monitor come anywhere near the real thing. It even has special self re-calibrating circuitry to correct for the aging of the CRT and driver transistors + corrects for ambient light. Every single other screen I've seen sucks royally by comparison. The latest 'Color Grading Grade' studio OLED screens, infinity to 1 contrast ratio, are supposed to be the fist to outperform the CRT I have with it's true ansi 1 million to 1 contrast ratio.
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A friend of mine spent most of his career as a broadcast engineer. He mentioned that the downfall of CRT displays has been a serious problem because nothing else can touch them in terms of proper color rendering and a lot of studio people refuse to use anything else. That's a problem because the tubes that were used in studio monitors were hand picked from the production lines making tubes for TVs and other less critical displays. Without the large scale mass production there's nowhere to hand pick the really premium tubes from. Even if they started building CRTs again they're never going to have such large volume to make that possible.
I have high hopes for OLED. LCD displays are crap, I have a decent one that touts something absurd like 80,000,000:1 contrast ratio which is absolutely stupid because the true contrast ratio is nowhere close to the old CRT I had previously.
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I have high hopes for OLED. LCD displays are crap, I have a decent one that touts something absurd like 80,000,000:1 contrast ratio which is absolutely stupid because the true contrast ratio is nowhere close to the old CRT I had previously.
Because of limitation of the polarizers on LCDs, their true ansi contrast ratio, without back light dimming trickery is only 800:1, viewed at a perfect perpendicular, or, optimum angle. The higher fake 80m:1 number you see is artificially achieved with a artificial gamma ramp, back-light modulation and further real time dynamic range processing (sorta like auto volume leveling, but done for the picture which you should be able to disable in your picture settings, but be warned, the picture will look dark and soft or pale, it will only look light on outdoor scenes on properly colored movies, but, the color will be more accurate.)
Disabling all these junk features on an OLED screen makes it's display a little darker than what you see at the store (brightness wars between adjacent screens, artificially brighter screens sell more at the expense of true color accuracy), but the color should be amazing especially if you feed RGB and disable all internal color processing.
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Yeah I know how they get the obnoxious inflated contrast numbers but that doesn't make it any less annoying. It's so stupid, hard to believe they're allowed to get away with crap like this. It ought to be obvious that 80M:1 is BS but a lot of people are clueless.
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A friend of mine spent most of his career as a broadcast engineer. He mentioned that the downfall of CRT displays has been a serious problem because nothing else can touch them in terms of proper color rendering and a lot of studio people refuse to use anything else. That's a problem because the tubes that were used in studio monitors were hand picked from the production lines making tubes for TVs and other less critical displays. Without the large scale mass production there's nowhere to hand pick the really premium tubes from. Even if they started building CRTs again they're never going to have such large volume to make that possible.
I have high hopes for OLED. LCD displays are crap, I have a decent one that touts something absurd like 80,000,000:1 contrast ratio which is absolutely stupid because the true contrast ratio is nowhere close to the old CRT I had previously.
How about plasma displays? I thought they were supposed to equal the CRT in terms of colour rendering.
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Plasmas are on the way out, and have the same drawbacks as CRTs of having their black point dependent on ambient light level.
Anyway "the downfall of CRT displays has been a serious problem" makes no sense to me.
Generating a technically accurate feed that is "calibrated" to a studio reference that needs a CRT to evaluate makes no sense at all when 95% of the viewers have an LCD TV. Use a calibrated LCD monitor and you're done.
Having worked with broadcast engineers they're usually extremely methodic and precise people aiming for theoretical technical excellence - but that is often completely pointless and they totally fail to consider how their feed is actually being viewed (and they're often behind the times, i.e. they do things the way they learned to do them 20 years ago even when that's now totally irrelevant, but it's impossible to make them change).
As a photographer who mostly posts online I have my monitor calibrated - but I regularly turn calibration off to remind myself that I probably don't need to spend 20mins to get the shades "just right" becasuse 99% of people will see it completely differently regardless of my efforts, these will only be worth to a few peers who also have a calibrated setup (hoping it's to the same references... which is not a given since there are multiple opinions there too).
What I do (and people probably should do in this day and age) is send the photo to a couple of mobile devices and make sure it looks as close to how you want it to look, and go with that regardless of how "technically correct" that ends up being because that's what >60% of your viewers will see. What photographers who do paper prints would do, i.e. find one print shop, running dozens of adjust/test print iteration cycles until they find just the good settings to get the desired output, then only using that print shop and no one else.
RGB histograms and vectorscopes are one thing, but given nobody apart from your fellow people in the same field has a calibrated monitor what you put out can and will end up being viewed in an infinity of broken ways before you hit one person who has the setup that will show what you intended. I have a wide gamut monitor - it's useless, my viewers don't, and a photo that's made to look great on it looks total crud on sRGB. So I adjust my pictures for sRGB to look good, which is extra work because I don't see what others get directly :scared:
Back to the initial point, even with a CRT or plasma the broadcast engineer will put out a nice image with a good black level when they are viewing that CRT in a dim studio environment - that even people who have a CRT/plasma capable of replicating it will view in their living room with the sun hitting the screen resulting in a totally washed out picture... and they won't give a damn, they won't even see or care about the difference if you put a nice TV with proper ambient light rejection next to it.
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It all has to do with getting the source colors right. Because, one day, displays will have perfect color, and then, If your source is off, you ruined your video recorded piece of art. Get it right the first time. Also, if your reference screen is a little strong on the pink and you adjust that out, maybe for the 33% of screens which have ok color, everything will look fine. The next 33% of screens which have a pink offset will look great, then, then last 33% which have a green offset, all the people's faces will have a yellow/green tint to them. What happens when a commercial comes on with proper colors next to you 'pink' compensated TV show or movie. As reference, it pays to have the high quality screen for the color grading department and even at their price, it's a minuscule price compared to the production as a whole.
Color corrected LCD screens are still crap, they may hit the color gamut targets, just not always so much so to the human eye. The newest QuantumDot LED backlights has improved eye comfort and color gamut significantly and I might get 2 for my desktop screen.
I'm waiting for the True QuantumDot OLED panels. To have that 85 inch screen consuming only 10watts on average, now we are talking... For now, I'm stuck with a DLP video Projector.
Only the truly expensive plasmas begin to get good, but their phosphor isn't as black as the some top end CRTs and they are filled with a gas which is bad for the environment (now banned in Europe). Cheaper plasmas, which don't use the same gas, have either off pixels, or, the next shade up is something like 33% grey. To get the shades inbetween, they PWM the pixels at a rate slower than the video frame rate. For those of use who can see it, it make dim shaded areas, especially still images, has a continuous moving grain within them.
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What gas are plasma screens filled with? I always assumed it was just argon or argon/xenon mix but I've never actually looked into it. I do like plasma screens a lot, they're the most CRT-like of any of the modern display technologies but as you say they're going away fast. LCD has taken up the vast majority of the market because it's so cheap now. There's a saying that "Good enough" is the biggest enemy of "the best" and that seems to be true here. LCD is good enough for a majority of consumers.
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Give it 5 years, OLED will get cheaper than LCD once the yield improves, or they go to quantum dot phosphor grid over a monochrome IR or Blue OLED panel radically simplifying manufacturing, eliminating the multi-color led layers printed on the substrate. No more angular discoloration and no reflective glare unless the display was designed with glare on purpose. And, off pixels are off, dead black.
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One can hope. OLEDs are starting to look like fusion reactors, they've been the next big thing for around 15 years now and progress has been painfully slow. For a while there were some nice small color OLED screens with decent resolution but those all seem to be gone now, all you can get are very small low res ones and large high end smartphone size.
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One can hope. OLEDs are starting to look like fusion reactors, they've been the next big thing for around 15 years now and progress has been painfully slow. For a while there were some nice small color OLED screens with decent resolution but those all seem to be gone now, all you can get are very small low res ones and large high end smartphone size.
LCD took from about 1970 to the early 2000s to get from elementary 7 segment displays to the big time for TVs, so OLEDs are still young. :).
OLED TVs were pretty nasty until 2016. The LGs looked great in a dim room, but the images looked like cartoons in a well lit room. The 2016 LG TVs finally solved that. You can crank them up to quite high brightness, and the picture still looks good. The price of those sets may be high, but its not far from the high end LG LCD sets of the same size.
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While a bit off topic, what I'd really love to see is a return of small 4:3 color OLED panels in either 320x240 or 640x480 resolution that I could use to build some miniature classic arcade games with CRT-like picture quality. I realize that's a niche application though.
I've decided though if I ever actually buy a new TV, it will be OLED and it will be flat. I've seen OLED TVs in stores but they've all been gimmicky curved screens, form over function. That said, I've never actually paid money for a TV, always managed to find more broken ones than I have a use for and fix them.
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OLED is pretty good indeed now since 2016. The FHD generation before the latest had huge gaps between pixels that was making them look horrid, but it got better with the 4K panels. Fill is still not to the level of LCDs so for my purpose it's still not a good thing.
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While a bit off topic, what I'd really love to see is a return of small 4:3 color OLED panels in either 320x240 or 640x480 resolution that I could use to build some miniature classic arcade games with CRT-like picture quality. I realize that's a niche application though.
I've decided though if I ever actually buy a new TV, it will be OLED and it will be flat. I've seen OLED TVs in stores but they've all been gimmicky curved screens, form over function. That said, I've never actually paid money for a TV, always managed to find more broken ones than I have a use for and fix them.
Start a new forum topic thread here. Solutions exist and may be fun to delve into...