Post by MovieBear1Nobody's talking about the cyan soundtrack mandated implementation &
its consequences?
I'll believe it when I see it.
MGM switches to cyan tracks in May. The Disney companies switch this
Fall.
I must have missed WHY the industry wants to switch to this type of soundtrack.
what are the advantages and disadvantages to them.
It's easier to do it by chronology:
First, there's the analog silver soundtrack, & its white light (tungsten)
reader. It's been the optical soundtrack since SOF, backwards compatible
all the way up to today, compatible even when adapted to Dolby's matrixed
multichannel sound, etc. This means all those movies with optical
soundtracks can be run from archives, in rep, etc. SMPTE held most of
this together.
Then, there was an improvement to the design of the reader, reverse scan,
which improved response & S/N. Existing installations using the previous
"forward scan" readers were not affected, but new equipment was improved.
Next came infrared LED readers, which replaced the tungsten exciter bulb.
In their reverse scan configuration, they achieved the best fidelity
performance of any reader configuration on the optical track.
Then, in 1995, Kodak, Technicolor, & Dolby began to work together to
create a means of eliminating silver soundtracks.
Ongoing reports from the dye track soundtrack viewpoint can be found at
http://www.dyetracks.org/
The system they designed was this:
Soundtracks would be printed in cyan, & read by visible red LED readers.
The foremost point of is this system The new cyan soundtrack read by red
LED readers would be incompatible with the old system of readers & prints.
Cyan soundtracks would not play on infrared readers, & on white light
readers played poorly. Existing silver tracks play poorly on the new
visible red readers:
"Following a show of Red Alert, Andrew Wales presented some examples of
variable density
analogue tracks printed normally, with high magenta, and cyan dye. For each
track type there
were three examples at slightly different densities. The subject matter was
Moulin Rouge
dating from the early 50s and the tests were played using a red light
reader. As expected
the normal tracks sounded particularly poor, with very quiet, distorted,
and spitty sound"
(from
http://www.dyetracks.org/reports/minutes/2001/TechnicolorFilmService.meeting
.min.0301.html )
The cyan proponents then announced that a conversion to cyan soundtracks
was underway, & new equipment would need red readers to play the upcoming
cyan
soundtrack. Since the 2 systems were incompatible, it was neccessary before
the changeover in soundtracks to support the new red readers by ensuring
that the soundtrack could be read by both red readers & IR/white light
readers. The High-Magenta soundtrack was implemented, a system which is
performs more poorly than either the cyan or silver soundtrack, but can be
read by either existing tungsten/IR readers or the red readers as they were
being installed. From that point to now, all soundtracks have been silver
or high-magenta, enabling the red reader installs as existing readers were
in
place.
The other issues mostly derive from the fact that the proposed system of
sound
reproduction of a cyan track on a red reader is noisier than the silver
soundtrack & white/IR reader system. Its only "improvement" is reverse-
scan,
which was existent before in tungsten & IR systems, which implemented it
with
better performance:
--------
http://www.dyetracks.org/ci.os.0012.reddye.html
See Figure 6
Red Readers, Silver, High-Magenta, and Cyan Analog Soundtracks:
Review and Status
by Paul R. Goldberg
Noise Performance
Tests have demonstrated that readers based on broad band tungsten, or white
light, illumination sources are quieter than readers based on narrow band
red LED illumination sources (660 ± 20 nm light energy spectrum). It is
believed that this is due to the fact that when the track is lluminated by
broad spectrum white light, the incoherent noise sources from each of the
film's
color layers add on a random basis and thus the noise "averages out." If a
narrow spectral band illumination system is employed, this averaging cannot
take place and thus the signal-to-noise ratio is impaired. This is true
whether a standard silver track, high-magenta applicated track, or cyan dye
track is being presented. It is also independent of the type of release
stock employed.
Figure 6 depicts this phenomenon for a standard silver track on Agfa
release stock. Note that in all cases the curves for the red reader
"look worse than they actually sound." This is because it is extremely
rare for the bias line to fully open during actual movie sound track
presentation.
Extensive listening tests at Dolby Laboratories have shown that the
use of Dolby SR encoded soundtracks, although not completely eliminating
the additional red reader noise, reduces its effect to the point that
air conditioner noise will significantly mask the problem.
-----------
(thanks to a very observant & admired fellow!)
It's interesting in passing that the air conditioning noise which THX's
theater improvement campaign tried to eliminate has instead become a
component to be included in the cyan soundtrack system.
The incompatibility issue is very significant for theaters (PAC's, art
houses, some independents) which run any combination of rep/current/art
fare. Prints with either track will sound bad on the wrong reader, so
which reader do you install? A permanently installed red reader yields
poor reproduction of silver tracks on films running from pre-high-magenta
to the dawn of SOF, an IR/tungsten reader cannot play new cyan tracks.
Switching readers is not as simple as switching a lens: an A-chain
alignment is required. There is a reverse scan reader which has this
versatility (visible red to IR), but the A-chain is easily beyond the
knowledge & equipment available to most operators. Another option is a
product which is a visible RED array which can replace the bulb in a
tungsten system: it is not reverse scan, & there are many reports of
it being troublesome in the field due to the resulting signal from
the cell being low. It requires a pre-amp between the cell & processor,
& is very sensitive to noise as the result of EMF & ambient light
(one tech tells the operators to run movies with the fluorescents off).
Switching readers between films is easily impractical.
The next problem is with existing libraries of prints that these venues
draw from. New prints of older titles are often struck, the new ones
will have cyan soundtracks. So a theater running rep fare cannot
know if the print that will show up will have one soundtrack or another.
New prints of black & white films will have silver tracks which are
optimized for red readers; in that case even visual identification of
the type of reader to use would be impractical. The folks running these
companies, likewise, cannot with any practicality determine what kind of
reader is in the theatre where a print is to be sent.
Older titles struck with new cyan tracks will have another problem which
is the same for any *new* title that is in mono. Since the cyan
soundtrack/red reader system is inherently noisier, Dolby SR is required
(see above). Older titles which are mono, when printed with their original
sound negatives, will have worse S/N than the silver tracks. That
would be true for any mono film, so all optical tracks will need to be
encoded with Dolby SR. Maybe Dolby will cut folks a break on this,
since the system is dependent on Dolby components being present: encoding,
processors, & all LED's supplied to visible red LED readers. Someone else
would be more likely to know if there are more components related only to
patents.
The concerns of incompatibility for theaters which would be faced with a
mix of soundtrack types was raised often in the minutes of the Cyan Track
Committee's meetings, but no resolution or further action was reported.
Practically, if you've got a theater, PAC or art house which runs these
programs, you will get a mix of soundtrack types. It is impractical to
switch readers, so film becomes impractical as a medium in that type of
programming. As more cyan-track films go into circulation, it would
make more economic sense to use video projection. The rep/art house/PAC
theaters, that type of programming, & the companies which provide them
with product are being pushed out of the boat.
Advantages: The labs save money, Dolby makes money. The processes the
lab saves on (which otherwise they'd have to solve at their own expense)
can be construed as good for the environment, so the 'film industry' can
claim PR of being environmtally-friendly.
Disadvantages: Incompatibility of titles, inferior analog soundtracks.
Non current-release programming & theaters lost.
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