BBC Aspect Ratio Change 1950

[G8KBG Tony]

Some rather wordy advice for viewers in the Radio Times, on how to correctly adjust their 5:4 sets to the new 4:3 standard. Advice, I feel, that would not be followed for long.

[Graham G3ZVT]

An I not right in thinking that rectangular 5:4 CRTs were being made well into the 1960s and the advice in Thorn service manuals was to set the height normally, and overscan the width so the test card "C"side castellations were off the screen?

What with the effects of changing mains voltage and general poor HT and EHT regulation on a typical domestic set, perhaps the BBC should have not even bothered to tell the public about the change.

It's a bit like when Radio 4 LW dropped by 2kHz, did anyone notice?

[peter_scott]

Same problem today fitting 16:9 into 5:4 or 4:3. My preferred option is to lose picture content at the sides instead of compressing the height.

Peter

[wd40addict]

I wonder why EMI picked 5:4 when 4:3 was already established as the cinema standard?

[kalee20]

Possibly because, with a circular CRT screen, masked-off, that gives a rectangle of slightly greater area?

The maximum area would be a square of course, but that's not so visually appealing, so 5:4 was the compromise.

(Actually, I thought TV aspect ratios were quoted as height:width traditionally, and cinema width:height)

[Dave Moll]

I can't say that I've ever seen TV aspect ratios quoted as height:width, i.e. 3:4 or 4:5 (and certainly not 9:16).

[G6Tanuki]

I wonder how many of the BBC's customers would have noticed the change?

And if they did they'd probably complain that "The damned gasometer down in Railway Cuttings is messing with the picture again", fiddle around with the vertical/horizontal hold controls and then go back to watching whatever interminably-worthy 'drama' was being broadcast that night.

[ms660]

I remember the CRT's that had a width to height ratio of 5/4, to get a circle on the test card the height was set as per normal and the width was set to over scan.

Lawrence.

[Graham G3ZVT]

Originally Posted by wd40addict

I wonder why EMI picked 5:4 when 4:3 was already established as the cinema standard?

The story I heard was 5:4 was chosen almost arbitrarily, by a relatively non-technical Marconi-EMI studio manager at Alexander Palace.

I am sure I have seen film footage of the person concerned reminiscing on how he felt unqualified to make the decision.

[Graham G3ZVT]

Originally Posted by Dave Moll

I can't say that I've ever seen TV aspect ratios quoted as height: width, i.e. 3:4 or 4:5 (and certainly not 9:16).

The film industry usually express them with 1 as the denominator

16:9 = 1.77:1
4:3 = 1.33:1

I have a piece of software that used that convention




(1.77 vs 1.78 is just a rounding issue apparently)



Then again sometimes they are expressed as ninths, 16:9 (obviously)
and 12:9 (4:3)

[raditechman]

Now we have two suffer another aspect ratio change with programmes made for TV like Dr Who or Around the world in 80 days being in the new format of Univisium a compromise between cinemas wide screen and TV wide screen
https://www.reddit.com/r/Filmmakers/...ing_over_film/

John

[Brigham]

The Baird system aspect ratio is often misquoted as 7:3, rather than 3:7.
Curiously, if you take into consideration the graduated scanning, the actual picture ratio is very nearly 1:2.

[Ted Kendall]

Originally Posted by rambo1152

I am sure I have seen film footage of the person concerned reminiscing on how he felt unqualified to make the decision.

This clip appeared on All Our Yesterdays - it would have been about 1971, given that the programme dealt with the events of twenty five years previously. If I remember right, this was the man appointed to be Controller of Television Service after the war. - Maurice Gorham, I think. He said almost the first piece of paper on his desk was to decide whether the aspect ratio should be 5:4 or 4:3. He frankly admitted he had no idea what this was about.

[stevehertz]

Originally Posted by wd40addict

I wonder why EMI picked 5:4 when 4:3 was already established as the cinema standard?

Because CRTs are (were) circular, thus enabling maximum usage of the CRT screen.

[FERNSEH]

After changing the aspect ratio from 5:4 to 4:3 in order to maintain the same number of picture elements per line, the bandwidth of the video was increased from 2.7Mhz to closer 3Mhz.
The active video part of a line was in those days about 81 to 82 microseconds.

DFWB.

[Heatercathodeshort]

My thoughts are that it was a bad move at the time. The change definitely reduced the size of the viewing area especially regarding the small tubes that were in use back then.

I suppose it was inevitable and a later change would probably have caused problems when picture tubes became larger. It was easier to change when viewing numbers were small.

The pictures show the differences showing between 5.4 and 4.3. PYE LV30 [1950], PYE D/B16T [1946] and Philips 683U [1949] Bush TV12 1949 and Bush TV22 [1950]

I believe replacement masks were available for some models but who would have bothered? John

[FERNSEH]

It's most likely the BBC was aware that the next generation of CRTs will have rectangular 4:3 aspect ratio faceplates.
The early 110degree CRTs introduced in 1958 did indeed have 5:4 screens.

DFWB.

[peter_scott]

I must say I don't like the American approach to round CRTs of vignetting the corners.

Peter

[Nuvistor]

Originally Posted by peter_scott

I must say I don't like the American approach to round CRTs of vignetting the corners.

Peter

You also may not like this 1951 Zenith, 165 sq in CRT, approx 14inch diameter.

[Sundog-]

It's surprising the variation in sensitivity to aspect ratio accuracy.
I'm fairly sensitive, cannot bear the regular inaccuracies. Many people would watch a 16:9 squashed onto 4:3 and visa versa without either noticing or being bothered.
A colleague (while doing QC) visually picked up a sub 1% line length inaccuracy due to a codec misconfiguration. Other staff had not noticed this for months.

And how do our eyes and brains compensate for off-axis viewing?