[opendtv] Re: More NTSC B&W to NTSC Color
- From: "Don McCroskey" <mccroskey2@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 6 Feb 2013 22:18:06 -0800
I can only speak for the practice used by ABC, Hollywood; but, as you
will see, there seemed to be only one practical choice.
ABC began color transmission (film only) it the fall of 1963 using the
RCA TK-26C film chain.
An RCA Color Frequency Standard,MI-40201A, generated the 3.58 MHz
color subcarrier which was fed to the colorplexer
and also divided down to a2H 31.4685 KHz pulse which was connected to
the external input of the RCA TG-2 sync generators.
From that point on, the whole plant operated on a 29.97 frame rate.
Switching to 30 fps for B&W was unnecessary and would
likely cause noticeable on-air disturbances and would have been very
upsetting to video tape recorders using the plant sync generators as a
reference.
Later, when TK-27 film chains were added to accommodate a near-all
color film schedule, it became necessary to disable the color burst
while black-and-white film was being run to avoid unwanted random
colorization on some home color sets.
This was not required if the program contained a mixture of black and
white and color sections.
Don McCroskey
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx
[mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Cliff Benham
Sent: Wednesday, February 06, 2013 8:03 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: More NTSC B&W to NTSC Color
The FCC rules for b&W broadcasting about shutting off the color burst
remained in place until the late 1970s or early 1980s when they were
changed because newer broadcast equipment could not deal with a video
signal that didn't include color burst. [Newer equipment was
synchronized with a single 'black burst' signal instead of the five H.
drive, V. drive, sync, blanking and subcarrier.]
I'm sure the networks as well as all the local stations continued to
broadcast at 30.00 Hz for B&W, switching to 29.97 for color broadcasts
during the B&W to color transition period which lasted well into the
1970s. I doubt there was any complete switch countrywide 'all at once'
switch to 29.97 until well after the to the B&W rule was changed.
Cliff Benham
On 2/6/2013 6:13 AM, Kirk Bayne wrote:
> I still don't understand how the transition from 30.00fps NTSC B&W
to
> 29.97fps NTSC Color was accomplished.
>
> Example: CBS broadcast some programs in Color from late 1953 till
> (full prime time color) 1966, did CBS switch from 30.00 to 29.97 for
> the Color broadcasts, then back to 30.00 for the B&W programs, or
did
> CBS use
> 29.97 for all Network broadcasts (B&W and Color)?
>
> Kirk Bayne
>
>
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts:
