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PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

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Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#11

Post by lb1lf »

stuaxo wrote: post #6
Taniwha wrote: post #5

Earlier quoted context omitted.

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…

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.

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.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#12

Post by maratc »

dannyw wrote: post #10
hilbert42 wrote: post #7

In Australia before the official introduction/launch date of PAL colour television in 1975 it was a requirement of the then, now defunct, broadcasting regulator, the ABCB - Australian Broadcasting Control Board for television stations to remove any colour content from their TV broadcasts. (During the conversion period leading up to the launch stations would run a mixture of B&W and colour material within their statio…

What was the benefit / reasoning for removing colour content?

Can't speak for Australia, but Israel in 1970's considered colour television as "a luxury that would increase social gaps"[0], and a similar colour burst erasing happened. This has lead to a rise of anti-erasing devices that reconstructed the colour burst, returning the colours.

[0] https://en.wikipedia.org/wiki/Color_killer

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#13

Post by [deleted] »

maratc wrote: post #12
dannyw wrote: post #10

Earlier quoted context omitted.

What was the benefit / reasoning for removing colour content?

Can't speak for Australia, but Israel in 1970's considered colour television as "a luxury that would increase social gaps"[0], and a similar colour burst erasing happened. This has lead to a rise of anti-erasing devices that reconstructed the colour burst, returning the colours. [0] https://en.wikipedia.org/wiki/Color_killer

[deleted]

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#14

Post by hilbert42 »

dannyw wrote: post #10
hilbert42 wrote: post #7

In Australia before the official introduction/launch date of PAL colour television in 1975 it was a requirement of the then, now defunct, broadcasting regulator, the ABCB - Australian Broadcasting Control Board for television stations to remove any colour content from their TV broadcasts. (During the conversion period leading up to the launch stations would run a mixture of B&W and colour material within their statio…

What was the benefit / reasoning for removing colour content?

The usual bureaucratic crap, the government wanted the kudos - grand opening etc. There was also the legitimate problem that some stations would be ready before others and thus have a leading economic advantage. (Also, there had to be a reasonable supply TV sets available.)

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#15

Post by avian »

Taniwha wrote: post #5
avian wrote: post #3

Earlier quoted context omitted.

> 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 telev…

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…

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.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#16

Post by mhalle »

Taniwha wrote: post #5
avian wrote: post #3

Earlier quoted context omitted.

> 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 telev…

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…

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.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#17

Post by immibis »

maratc wrote: post #12
dannyw wrote: post #10

Earlier quoted context omitted.

What was the benefit / reasoning for removing colour content?

Can't speak for Australia, but Israel in 1970's considered colour television as "a luxury that would increase social gaps"[0], and a similar colour burst erasing happened. This has lead to a rise of anti-erasing devices that reconstructed the colour burst, returning the colours. [0] https://en.wikipedia.org/wiki/Color_killer

Wow, caring about social gaps. Unthinkable today.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#18

Post by fortran77 »

avian wrote: post #15
Taniwha wrote: post #5

Earlier quoted context omitted.

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…

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.

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.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#19

Post by tialaramex »

fortran77 wrote: post #18
avian wrote: post #15

Earlier quoted context omitted.

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.

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.

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.

Re: PAL Colour Recovery from black-and-white ‘telerecordings’ (2008)

#20

Post by cf100clunk »

powlow wrote: post #8

This is from 2008 - what are the newer developments in this space?

Digitization, colourization, audio resampling, and other computer-based treatments of original recordings have taken over as restoration techniques from what are now archaic analogue-based techniques.
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