Film-Tech Forum ARCHIVE: How do Cyan tracks save resources?

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Posted by Clive Carmock (Member # 2882) on 11-28-2005, 04:33 PM:

I wonder if anyone could help me with a question. I have tried to find the answer to this, but as yet can't find the information so far.

I understand the arguments in favour of Cyan Dye tracks, but am left wondering - does the Cyan dye itself require development? Ie is is photographic emulsion in the same way the picture portion of the film is?

If it is why does it use any less developer than a black track? I assume the traditional type of analogue track required a different developer than that used for the main picture area. Was the emulsion for that of a higher silver content maybe?

Could a standard colour emulsion not have been used and exposed to produce a black & white soundtracks that could be developed using the same developer and associated chemicals as the picture area.

I know that there must be very good answers to these questions, but these are points I've wondered for a while.

Regards
Clive

Posted by Mike Blakesley (Member # 26) on 11-28-2005, 07:00 PM:

Pollutes water less, and saves $$. Those are the two big points. I'm sure John P. will pop in here in a minute with a few dozen links, and you can search the site here (try the word "cyan") and learn all you want to know.

Posted by Louis Bornwasser (Member # 3063) on 11-28-2005, 07:04 PM:

Answers: www.dyetracks.org Louis

Posted by Gordon McLeod (Member # 33) on 11-29-2005, 08:22 AM:

COlour emulsion even if all layers are exposed will still be a dye image and as such relatively passive to IR which excitor lamps emit in large amounts To make it readable the track must have metalic silver left in it to block the IR spectrum and this requires a second development stage that is done either with an aplicator wheel or spray of a very viscous caustic developer> Then the print must be rewashed
The rewashing use a very large amount of water that is waste and even must be treated before being dumped
Also the applicators at high speed are prone to splattering or weeving that can lead to purple or brown blotchs or a ragged edge to the actual picture area

Posted by John Pytlak (Member # 331) on 11-29-2005, 09:03 AM:

The details of the relatively complex procedure of "soundtrack application" are in the Kodak H-24 processing manual:

Kodak H-24.02 Processing Equipment

quote:
Sound Track Processing Equipment
The procedures for sound track processing on EASTMAN
Color Print Film, are described in Module 9, Process
ECP-2D Specifications. A close-up of the required
equipment is shown in Figure 9-6. Because sound track
processing is a precision operation, the required equipment
must be kept in top operating condition.
Alignment
Maintain the venturi air squeegees in alignment, and the gaps
specifications.
To keep the applicated sound developer in the sound track
area of the film, maintain the proper alignment between the
guide rollers and backup roller relative to the applicator
wheel. Also maintain alignment in the idler roller assembly
to eliminate vibration and film twists.
Keep the spray jets and squeegees aligned in the wash box
to prevent contamination of the picture area with sound track
developer.
Align the sound-track application detector, if used.
Check the alignment of the application equipment each
time the processing machine is prepared for sound track
development. Check the gaps between the backup roller and
the applicator wheel during normal machine maintenance.

Kodak H-24.09 ECP-2D Process Specifications

quote:
OPTICAL SOUND PROCESSING
Overview
The sound track is printed onto KODAK VISION Color
Print Film / 2383, KODAK VISION Premier Color Print
Film / 2393 and KODAK VISION Color Teleprint Film /
2395 / 3395 from a negative sound original. Only the top two
emulsion layers should be exposed. This can be
accomplished by using a filter pack comprised of KODAK
WRATTEN Gelatin Filter No. 2B* and No. 12 in the light
beam.
In Process ECP-2D, the developer produces a positive
silver and dye image of the sound track. The first fixer
removes undeveloped silver halide from the sound track
area. Next the bleach converts the silver sound track image
back into silver halide. A sound developer is inserted
between the bleach wash, which should be a 40-second deeptank
wash, and the second fixer.
This fogging developer reduces the silver halide in the
sound track to a positive silver image once again. The silver
and dye sound track image is not appreciably affected by the
remaining processing steps.

(Read pages 9-32 to 9-37 to get an appreciation for the complexity of the added steps and the QC issues involved)

As you can see, lots of issues just to put that narrow band of silver on each print to make them compatible with old tungsten exciter lamps. Plus, if the prints are not properly recycled, that silver (a "heavy metal") ends up in fly-ash or a landfill. With over 10 BILLION feet of color prints made every year, the environmental impact is significant.

Posted by Peter Mork (Member # 1336) on 11-29-2005, 11:43 AM:

Let's not always see the same hands!

To answer the questions you asked:
> does the Cyan dye itself require development? Ie is is photographic emulsion in the same way the picture portion of the film is?
You got it - track and picture get developed in one swell foop.

>If it is why does it use any less developer than a black track? I assume the traditional type of analogue track required a different developer than that used for the main picture area. Was the emulsion for that of a higher silver content maybe?
The emulsion's the same, you just have to process it differently to retain the silver, hence the extra steps.

>Could a standard colour emulsion not have been used and exposed to produce a black & white soundtrack that could be developed using the same developer and associated chemicals as the picture area?
Conceivably yes, but manufacturing film with a different type of emulsion for the track area would be very expensive. (Film is produced and coated in massive sheets which are slit to width and then perforated - I reckon trying to do it your way would have its own set of problems, and cost a bundle.)

Posted by John Pytlak (Member # 331) on 11-29-2005, 02:16 PM:

quote: Peter Mork
(Film is produced and coated in massive sheets which are slit to width and then perforated - I reckon trying to do it your way would have its own set of problems, and cost a bundle.)

Yes, Kodak coats ("sensitizes") the film as wide rolls, about 54 inches across and well over 10,000 feet long. The rolls are then slit to 38 35mm strips, and then perforated. The emulsion properties are the same across the entire width of the roll, so you cannot make film with a different emulsion in the soundtrack area.

For a silver+dye soundtrack, the lab uses the special "soundtrack application" equipment, chemicals and procedures outlined in the Kodak processing manual:

1. Viscous caustic soundtrack developer containing hydroquinone
2. An extra fixer solution before the bleach ("First Fix")
3. Partial drying after the bleach wash
4. Precise application to only the analog soundtrack area, done on wet film moving at many hundreds of feet per minute
5. LOTS of fresh water to wash the developer off without splashing back into the picture area, causing stains
6. Extra QC to be sure the sound application has no defects

A red LED is efficiently modulated by cyan dye, and requires no silver in the track.

Old tungsten light readers have lots of IR sensitivity, that requires silver to effectively modulate

Posted by Clive Carmock (Member # 2882) on 11-29-2005, 03:28 PM:

Thanks for all this information that has certainly cleared up a few questiosn I have had. I didn't realise the IR element was so significant and hence the requirement to retain more silver in the developed track to block that.

It all makes perfect sense now.

Best wishes
Clive

Posted by Stephen Furley (Member # 1277) on 11-29-2005, 04:20 PM:

Using the standard colour print stock a dye track of any colour could be produced, depending on which layers were exposed. The reasons for not using the yellow layer have been discussed here previously, but why use the cyan layer? Why not the magenta layer with a green light? I assume that the cyan layer must have some advantage over the magenta one; or is it that red light sources have some advantage over green ones.

CDS used the magenta layer, but I think the reader used white light; I assume with a green filter in the path someware. Or was the ccd reader only green-sensitive?

Why not remove the silver, but still use both cyan and magenta dyes, as in a conventional track? This could still be read with a red light, or come to that, a green one. Is it that a sharper image is produced by using just one layer?

Anybody who is old enough, like myself, to have worked with the C22 Kodacolor process, and E2/E3 Ektachrome, will appreciate how much colour processes have been simplfied in the last 35 years or so. (C41 really has been with us a long time now, hasn't it? I was still at school when Kodacolor II was introduced.) To be honest, I'm rather surprised that the silver re-development process wasn't eliminated long ago.

Posted by John Pytlak (Member # 331) on 11-29-2005, 09:33 PM:

Generally, red LEDs were the most robust and readily available visible light sources at the time LED readers were being developed. I believe some of the technology was helped by the demand for bright long-life red LEDs in stoplights and other signalling devices. Cyan dye efficiently modulates red light.

Using cyan + magenta dye would offer little advantage, as both dyes are still quite transparent to the infrared light in a tungsten light reader. As noted elsewhere, the blue record (yellow dye layer) of print has not been used for soundtracks because it is the least sharp and most grainy.

Posted by Gordon McLeod (Member # 33) on 11-30-2005, 12:46 AM:

Quote "To answer the questions you asked:
> does the Cyan dye itself require development? Ie is is photographic emulsion in the same way the picture portion of the film is?
You got it - track and picture get developed in one swell foop."

That is a dye track and the best HF response is if the cyan layer only is exposed

quote"If it is why does it use any less developer than a black track? I assume the traditional type of analogue track required a different developer than that used for the main picture area. Was the emulsion for that of a higher silver content maybe?
The emulsion's the same, you just have to process it differently to retain the silver, hence the extra steps.

Could a standard colour emulsion not have been used and exposed to produce a black & white soundtrack that could be developed using the same developer and associated chemicals as the picture area?"
That is what a dye track is there is no redevelopment involved that a older dye+silver (that is required for a excitor lamp to work)
quote"Conceivably yes, but manufacturing film with a different type of emulsion for the track area would be very expensive. (Film is produced and coated in massive sheets wQuote "hich are slit to width and then perforated - I reckon trying to do it your way would have its own set of problems, and cost a bundle.) "
Even the revered IB tech looked at useing a DIAZO type cyan track several times to eliminate the need for the receiver stock being photosentised

Posted by Matt Whitney (Member # 2909) on 09-09-2006, 06:19 PM:

We just starting running "An Inconvenient Truth" this weekend. I was surprised and a little amused that it was not printed with the environmentally friendly cyan soundtrack.

Posted by Blaine Young (Member # 3992) on 09-20-2006, 01:49 PM:

We had 3 prints of "Talladega Nights", which did not have a Cyan track.

Blaine

Posted by Steve Guttag (Member # 268) on 09-20-2006, 05:13 PM:

And one of the few SDDS-8 films out at the moment.

Posted by Blaine Young (Member # 3992) on 09-21-2006, 12:59 PM:

Two prints just arrived of "All the Kings Men", printed in Canada and do not have a cyan soundtrack.

Posted by Martin McCaffery (Member # 37) on 09-22-2006, 02:31 PM:

quote: Matt Whitney
We just starting running "An Inconvenient Truth" this weekend. I was surprised and a little amused that it was not printed with the environmentally friendly cyan soundtrack.

We open tonight. I was hoping to find some compact flourescent lamps for the projectors [Wink]

Posted by Blaine Young (Member # 3992) on 09-22-2006, 03:15 PM:

It almost appears that anything produced by Deluxe in Canada doesn't utilize a Cyan soundtrack. Once I was able to determine print origin, it would appear that all of the prints I broke down yesterday (nine of them) without a Cyan soundtrack were printed by Deluxe in Canada. Is the Cyan Sountrack issue limited to US printers only?

Posted by Stephen Furley (Member # 1277) on 09-22-2006, 05:27 PM:

I don't know about Canada, but French labs seem to have been printing just abput all cyan for some time now; British labs are some way behind, but it's increasing.

Posted by Gordon McLeod (Member # 33) on 09-22-2006, 09:25 PM:

Deluxe Canada prints cyan all the time
They will print whatever the customer asks for or that the sound negative is set for