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The "Standard Academy Leader" and cue marks came into general use in late 1930.
Before that, leaders and cues, as we now know them, were pretty much non existent.
Many of the markings you see on leaders, like "Picture Start" and "Sound Start" are really
of more use to laboratories in lining up the negatives for printing the film than they are in
the projection room. The 'clock wipe' or TV leaders which count down in seconds came
about in the early days of TV, when stations had to cue commercials or programs for air.
I noticed that a couple of the frames in the original post, had some numbers burned into
them, like in the example below. These images either came from a print that was made
from a video source, or vice-versa, and more likely, these were screenshots of a film
that had been transferred to video for editing or airing. I worked for several years as
a 1" Broadcast Videotape editor, and "LTCR" stood for 'Longitudinal Time Code, which
was one of two types of time code commonly in use when I was working. The other
was "VITC" or 'Vertical Interval Time Code' . The difference was that Longitudinal Time
Code was usually laid down on one of the spare audio tracks available on a 1" tape
machine, and so, being basically an audio signal, it could not be accurately read at
either very low, or very high tape speeds, both of which are encountered when shuttling
while editing. When the signal became too distorted to read, the machine would start
counting frame-sync pulses, which was pretty close, but not 'frame accurate' . When
you slowed down to a readable speed again, it then switch back to reading the actual
time code and begin counting accurately again.
"Vertical Interval TIme Code" was embedded into one of the unused lines in the Vertical
Blanking Interval of a video signal. (Typically line 19 or 21, I think.) Vertical interval
Time Code could be read accurately at almost any tape speed, and even when the
tape was paused. Most later models of professional vidoetape decks were able to
handle both types of time code. I'm not sure about the example below, but do you see
the 'box" after LTCR? On some readers I worked with, that sometimes signaled if the
machines were working with "regular" or if they were reading "DTFC". (Drop Frame
TIme Code) which counted in such a way that compensated for the 29.97 frame rate
of NTSC TV. The "RT" reader on the left could mean either ""REEL TIME" or "RUN
TIME" depending on how your system was set up. The RT read-out did not always
match the Time Code readout. If you didn't compensate for the 29.97 frame rate,
there would be a 3.6sec per hour difference between the time reading and "Real" or
'Running" time readout. Not too bad for editing purposes, but the cumulative time
errors would have caused issues back in the days of split-second timing on Network TV.
LTCR_PIC.jpg
Before that, leaders and cues, as we now know them, were pretty much non existent.
Many of the markings you see on leaders, like "Picture Start" and "Sound Start" are really
of more use to laboratories in lining up the negatives for printing the film than they are in
the projection room. The 'clock wipe' or TV leaders which count down in seconds came
about in the early days of TV, when stations had to cue commercials or programs for air.
I noticed that a couple of the frames in the original post, had some numbers burned into
them, like in the example below. These images either came from a print that was made
from a video source, or vice-versa, and more likely, these were screenshots of a film
that had been transferred to video for editing or airing. I worked for several years as
a 1" Broadcast Videotape editor, and "LTCR" stood for 'Longitudinal Time Code, which
was one of two types of time code commonly in use when I was working. The other
was "VITC" or 'Vertical Interval Time Code' . The difference was that Longitudinal Time
Code was usually laid down on one of the spare audio tracks available on a 1" tape
machine, and so, being basically an audio signal, it could not be accurately read at
either very low, or very high tape speeds, both of which are encountered when shuttling
while editing. When the signal became too distorted to read, the machine would start
counting frame-sync pulses, which was pretty close, but not 'frame accurate' . When
you slowed down to a readable speed again, it then switch back to reading the actual
time code and begin counting accurately again.
"Vertical Interval TIme Code" was embedded into one of the unused lines in the Vertical
Blanking Interval of a video signal. (Typically line 19 or 21, I think.) Vertical interval
Time Code could be read accurately at almost any tape speed, and even when the
tape was paused. Most later models of professional vidoetape decks were able to
handle both types of time code. I'm not sure about the example below, but do you see
the 'box" after LTCR? On some readers I worked with, that sometimes signaled if the
machines were working with "regular" or if they were reading "DTFC". (Drop Frame
TIme Code) which counted in such a way that compensated for the 29.97 frame rate
of NTSC TV. The "RT" reader on the left could mean either ""REEL TIME" or "RUN
TIME" depending on how your system was set up. The RT read-out did not always
match the Time Code readout. If you didn't compensate for the 29.97 frame rate,
there would be a 3.6sec per hour difference between the time reading and "Real" or
'Running" time readout. Not too bad for editing purposes, but the cumulative time
errors would have caused issues back in the days of split-second timing on Network TV.
LTCR_PIC.jpg
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