In article ,
Graham. wrote:
There does seem to be a little mystery surrounding the change, but
apparently the original choice of 5:4 was made almost arbitrarily by a
non-technical manager, presumably in 1936.
I am sure I heard the man in question saying this in an interview shown
on an earlier anniversary programme, probably the 50th in 1986.


The first display tubes were round - and 5:4 make better use of that.
It's the simplest explanation.

--
*Where do forest rangers go to "get away from it all?"

Dave Plowman London SW
To e-mail, change noise into sound.

On 07/11/2011 10:07, Dave Plowman (News) wrote:

The first display tubes were round - and 5:4 make better use of that.
It's the simplest explanation.

Yes, also (FWIW) 5:4 was a well-established ratio for photographic
prints - 10" x 8" being common for enlargements.

As to 'Academy Ratio'
http://en.wikipedia.org/wiki/Academy...hnical_details says:

"The Academy ratio is not created in the camera, which has continued to
use the full frame silent aperture gate for all 4-perf spherical
filming. Rather, it is created in the married print, when the optical
soundtrack and frame lines are added."

Could it be that prints for telecine were different from those for
cinema projection? In the same section that I cited earlier Pawley
talks about a move away from optical soundtracks to magnetic tape
('sep-mag' AIUI) or separate film, but he doesn't give dates. Any
telecine experts around?

--
Andy

In article ,
Andy Wade wrote:
Could it be that prints for telecine were different from those for
cinema projection?

Don't think so. At one time (IIRC) they tried to get a new print (before
it was used in the cinema) - but having a special print made for TV would
have been pretty expensive.

In the same section that I cited earlier Pawley
talks about a move away from optical soundtracks to magnetic tape
('sep-mag' AIUI) or separate film, but he doesn't give dates. Any
telecine experts around?

Not having read it was he referring to cinema films or telerecording?

--
*Did you ever notice when you blow in a dog's face he gets mad at you? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 07/11/2011 17:16, Dave Plowman (News) wrote:

Don't think so. At one time (IIRC) they tried to get a new print (before
it was used in the cinema) - but having a special print made for TV would
have been pretty expensive.

Expensive, but small compared to the rights/royalties?

[Pawley]

Not having read it was he referring to cinema films or telerecording?

Telecine for 35 and 16 mm films. After discussing the video aspects he
says:

"The sound component of a video transmission was at first derived from
an optical track on the film, but later a magnetic sound track was
introduced, either on the same film as the picture, or on a separate
film synchronised with it. The use of a magnetic track gave a great
improvement in sound quality compared with an optical soundtrack,
especially if the latter had undergone several stages of dubbing before
reaching the final positive film. [62]"

(The Reference [62] cites a Science Museum publication of 1934!)

This is followed immediately by the paragraph about the aspect ratio
change that I quoted earlier.

--
Andy

On 03/11/2011 13:45, Terry Casey wrote:
In ,
says...


IIRC, the original 25" colour tubes were 5x4. Presumably because of the
difficulty in making a 4x3 that size? Or was it because they were US spec?

If it was a problem to make a large 4x3 colour tube, the same might have
applied to B&W?

The problem was protecting the viewer in the event of the tube imploding
but had been resolved before colour started in the UK.

Originally, tubes were round - including US Colo(u)r tubes.

As glass technology improved, rectangular CRTs became available but, as
I said earlier, larger sizes tended to be a bit rounder. The first 17"
110 degree tubes were particularly rotund.

Glass technology obviously improved because tubes got squarer again,
thus the diagonal of the 17" tube increased to 19" (and 21" to 23").

Of course, all of these tubes hid behind a thick plate glass
(occasionally Triplex) implosion screen, just in case ...

There were two early attempt to do away with this protection in the
early 60s. One involved bonding a thick plastic faceplate to the front
of the glass one whilst the other involved wrapping the front of the
tube in a tough, flexible sheet of plastic which had little dimples on
the inside to space it off the glass.

I don't recall the first of the two techniques you mention
I would be interested to learn more.

The second technique I remember well, I fitted hundreds of those "cornea
guards" to the faceplates of 19 and 23 inch monochrome CRTs
They were also colloquially known as "skins".
If a CRT needed to be replaced, a new skin would be applied, this is
because the old one would have discoloured somewhat, and it was almost
impossible not to trap dust particles if you reused the old one.

Modern health and safety would have had a dickey-fit if it had been
around in the 1970s
Goggles were available, full face visors came in much later.

The skin was held onto the CRT with a metal band that wrapped round the
faceplate and was tightened up with a 4BA bolt by means of a nut spinner.
The four corner lugs that secured the CRT into the cabinet were fitted
between the band and the plastic skin.

We sat on tall wooden bar stools when working at the bench, and one of
these would be employed to hold the CRT after removing the padded seat.

I imagine when manufactured, this would be done in some sort of oven. In
the workshop a hair dryer wasn't really up to the job, so a small
fan-heater was used to soften the plastic to make it conform to the
profile of the tube.
A hammer (yes I did say a hammer) was used to tap the four corner
brackets into position so they were aligned to fit the bolts in the
cabinet before finally tightening up the band.

I don't recall the dimples on the inside, as I recall, the object was to
heat the plastic and try to stretch it into intimate contact with the
glass by carefully hammering the corner lugs!

--

Graham.

%Profound_observation%

In article ,
Andy Wade wrote:
Not having read it was he referring to cinema films or telerecording?

Telecine for 35 and 16 mm films. After discussing the video aspects he
says:

"The sound component of a video transmission was at first derived from
an optical track on the film, but later a magnetic sound track was
introduced, either on the same film as the picture, or on a separate
film synchronised with it. The use of a magnetic track gave a great
improvement in sound quality compared with an optical soundtrack,
especially if the latter had undergone several stages of dubbing before
reaching the final positive film. [62]"

(The Reference [62] cites a Science Museum publication of 1934!)

This is followed immediately by the paragraph about the aspect ratio
change that I quoted earlier.

I dunno when magnetic film became available. I doubt it was anywhere near
as early as '34. My guess is post WW2.

Magnetic stripe was never universal in cinemas - it simply wore out too
quickly. Long before the optical side. Sepmag was only used in larger
cinemas - optical continued in others. And of course Dolby digital optical
was the final solution with excellent quality and lasted the life of the
print.

--
*Some days we are the flies; some days we are the windscreen.*

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 05 Nov 2011 13:40:33 +0000 (GMT), "Dave Plowman (News)"
wrote:

Generally, the broadcasters do this too when inserting 4:3 material into a
16:9 programme. Regardless of just how bad it makes the original 'framing'
look. It's obviously 'what the public wants'.

It's bloody annoying when a 16:9 programme contains old documentary
footage which is stretched sideways. There was a raft of that on the
run up to Remembrance Day - some was done ok, with black bars, other
stuff wasn't done at all well. Sheer bloody carelessness.

On 14/11/2011 15:12, Grimly Curmudgeon wrote:
It's bloody annoying when a 16:9 programme contains old documentary
footage which is stretched sideways. There was a raft of that on the
run up to Remembrance Day - some was done ok, with black bars, other
stuff wasn't done at all well. Sheer bloody carelessness.

It's sad that I find myself thinking that they _haven't_ spoiled it when
they don't do that. Or the equally annoying crop, often through the
eyebrows of the people in shot.

They're happy with old film in B&W; why can't they be happy that it's 4:3?

Andy