[avian]

> Black&White-tv was almost HD, 625x625. Then they added 3Mhz color-carrier in 1966 and it was 300x300

Maybe adding color did decrease the luma bandwidth and hence the horizontal resolution. I'm not sure about that. I think bw signals just used less bandwidth overall.

But in no way did color decrease the number of lines in the image. Those are defined by the scanning raster and remained the same in color and bw television.

[Taniwha]

It's more obvious in US NTSC that the PAL being discussed here .... essentially the colour subcarrier was put way out in the high freq part of the luma signal - display - anything with too high a bandwidth and it stomps on the colour - you've all seen this happen on analog TV ... and it has had profound effects on fashion .... let me explain ...

So what does "high frequency luma" mean? it means that the brightness of a signal horizontally along a line goes rapidly from dark to bright and back again - if that happens it stomps on the colour sub carrier and the colour goes wonky.

S-video is just a cable that puts the 2 signals on different wires so this doesn't happen.

So it turns out that the things that are the worst for this are things like checked or p;laid shirts/ties/dresses, tartans, houndstooth jackets etc etc - Think about what happened to fashion in the 70s/80s as colour TV became ubiquitous, people on TV started wearing solid colours, they didn't want to be the person who's whole body was a crawling mess - and people in the rest of the world started wearing the same sorts of styles - all those 50s/early 60s styles with checks and plaids you see on old game shows, all gone, not because of some big change in fashion - but because they could no longer be represented in popular culture.

[stuaxo]

I remember going to the US in 1998 and being shocked at how bad NTSC TV looked compared to PAL, the colours just looked wrong.

[lb1lf]

Back when I used to moonlight in video production, the quip was that NTSC was an acronym for 'Never Twice the Same Colour'.

The French SECAM system? 'Something Essentially Contrary to the American Method'

I'll lead myself out.

[cf100clunk]

SECAM was also jokingly called "Système Électronique pour Confondre les AMéricains"

[cf100clunk]

For technical reasons inherent in the chosen standard, NTSC TV sets required hue and color knobs, unlike PAL and SECAM. This effectively left it up to the consumer to adjust those values, with no accounting for variances in eyesight or taste. Unfortunately it meant that entire households had to endure the choices of whomever (Dad?) controlled the TV. On visits to others' homes it was painful to see how apallingly bad some peoples' preferences were. With PAL and SECAM the hue and colors were set to a standard, and that was that. Having said all that, the 29.97fps frame rate of NTSC was much easier on the eyes than the flickering 25fps of PAL and SECAM.

[Aloha]

NTSC adopted the color system it did because the cost of delay lines was considered to be too high, PAL also was more technically complex and probably would have delayed the adoption of Color TV, which was unacceptable to RCA.

The US oft has this problem, we tend to be early adopters of technology on a wide scale, so by the time a thing comes along that solves most of the inherent problems in the v1, we already have a wide scale implementation of the thing. This happened with TV color, phones (24 Channel T1 vs 32 channel E1 and aLaw/uLaw), credit cards (mag stripes), and all sorts of other things.

SECAM had some real advantages, but made working with composite signals hard, because of their FM nature. PAL and NTSC are reasonably close conceptually, and frankly so is PAL, you can easily encode PAL into SECAM, because it's mostly the composite signals that are different.

NTSC was originally 525 lines/60 fields per second (odd/even lines) giving an effective refresh of 30 fps, the 525 lines itself was dictated by our 6MHz channel width, and the field refresh by our 60Hz power. When they added color, they dropped the field refresh down to 59.97 to deal with a beat frequency issue between the color subcarrier and the audio subcarrier.

[Taniwha]

I'm guessing that watching PAL/SECAM requires slightly slower phosphors that NTSC and you'd see flicker on a modern computer monitor designed for 60-75 HZ ....

[briantw]

Did you try and adjust the hue? That was a necessary step in getting the colours right over in NTSC land. If you didn't adjust it, yes, you got pictures that were too magenta or too green. That said, I have an NTSC LaserDisc player still plugged in today, and if the hue is appropriately set, the colours are perfectly fine.

[Aloha]

NTSC and PAL had very very different color gamuts.

[Taniwha]

Yes - in the US HDTV was a revelation for many people because of the much larger colour gamut, it was just so much better, in Europe is was mostly just bigger

[avian]

None of this supports the parent's claim that TV went "from black&white 625x625 to color 300x300", which is just wrong on several levels.

[fortran77]

But there's some truth in this statement!

The "Luma" resolution is, in theory 625x625, but the "chroma" resolution is approximately 1/4 of that. That's OK, because the way our eyes work.

So "detail" remains at the 625x625 resolution, but the color information isn't that high. And our brains fill in the rest.

[tialaramex]

Digital video chroma sub-sampling literally has quarter chroma resolution in 4:2:0 video which is or at least was fairly common for live action stuff. It's obviously not going to be great for recording output from a computer, with sharp coloured edges, but live action scenes look fine.

I don't think anybody would claim that their 4:2:0 Blu ray has "low resolution" because it used chroma sub-sampling.

[timonoko]

> None of this supports the parent's claim that TV went "from black&white 625x625 to color 300x300", which is just wrong on several levels.

Obviously no one here has experienced pure crystal-clear BW-tv and what happened when they turned the color-carrier on. You had to adjust the focus so that horizontal resolution was below 320. And of course the vertical focus was similarly affected, as there was no separate screws for that.

[mhalle]

Crosstalk between luminance and chrominance signals are called dot crawl (chominance signal interfering with the luminance signal causing spatial artifacts) and chroma crawl (luminance signal stepping on the chrominance signal causing color artifacts).

I believe chroma crawl was generally more of an issue with NTSC, if the luminance signal wasn't sufficiently band limited.

[timonoko]

> But in no way did color decrease the number of lines in the image.

But it did. If you did not want to see the annoying 3Mhz color-carrier on your BW-TV, you had adjust the focus to 300 horizontal lines, which affected the vertical focus too.