We have both red LED and IR readers. We are presently changing to the red LED's, but not because of our concern for the environment; It's because we're worried the studios will suddenly drop cyan tracks on us just like polyster film, and we won't be able to play them.

It costs about $250 for a conversion kit (we use mostly Component Eng.) and it takes about an hour to install it and modify the power supply. (It takes a little longer because we have to remount the power supply in a way to allow easy accesss to the voltage adjustment- something we did not need to worry about with IR's.) So, installation alone costs $300 per screen, to replace something -working- we already have. And that's not even consitering whether or not red LED's are equal in sound quality.

The red LED's require a lot more tweeking than the IR's. It doesn't take long to tweek up the red LED's, about 15mins. We now have about 120 screens with them; And so now (in addition to everything else) I have a 15 x 120 (repeated every 6 months) maintaince task to do.

It's a moot point at our chain, since we have been buying new equipment, which came with red LED's and we are mostly converted. But, I do have to side with Steve on this. It's costing us (and will continue to cost us) a significant amount, with no gain for the theaters. If the environment is the major cause, I think the same amount of money could be better spent elsewhere.

"Now recent developments in LED manufacturing have resulted in the appearance of very bright white LED's. One can envisage that it may now (or very soon) be possible to produce a super-bright white TO46 bar-LED of the type used in reverse scan readers. Would it be a sensible proposition to investigate the use of a super-bright white light source with black dye only tracks, before introducing cyan? At first glance, this would appear to solve all backwards compatibility issues and result in lower film noise than with cyan. Silver would not be required because a white LED would (I expect) produce very little infrared energy."

Optical soundtracks have always been printed in the cyan and/or magenta records of color print film, to avoid using the less sharp and more grainy yellow layer. (Print films require a very fast blue-sensitive (yellow dye forming) layer because they are printed from negatives having an orange mask, and on printers with low color temperature tungsten light sources). So a broad spectrum white (tungsten lamp or "white" LED) light source would NOT be ideal, since they would either "see" the noisy yellow layer, or the "gap" in spectral dye density if the yellow layer was not printed.

A dye track could be printed in either the cyan or magenta layer, or both. Because of the very large installed base of red LED readers (the majority of theatres already have them), and the greater efficiency of red LEDs over green LEDs, the technology has been optimized around red LEDs.

Here is the spectral dye density curve for KODAK VISION Color Print Film 2383 (other manufacturer's print films have similar curves):
http://www.kodak.com/global/images/en/motion/products/lab/Ti2397d.gif

As you can see, the spectral output of Red LED's nearly coincides with the peak of the cyan dye density, making them the ideal light source. You note that your company is working on further improvements to reverse scan readers using Red LEDs. Improvements like these are likely to overcome the -2dB S/N loss of today's technology.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

The same silly arguement was applied to the cyan track with SR that somehow SR would cover up the 2dB drop in S/N...when compared to a convetional print the cyan print is still at BEST 2dB inferior...and that is presuming everything is perfect.

Steve

Looking at the big picture, many think dye tracks are the greater good. As far as the viability of red LED readers, over half of the theatres in the world have survived the conversion, and probably have better and more consistent analog sound than before (mostly because of the reverse scan LED technology).

As reader and noise reduction technology improve, you can use them to improve the quality of analog sound, which is becoming more and more of a "backup" as digital sound becomes predominant. Or you can use the improvements to eliminate a significant source of print waste, quality problems, and environmental impact, while still maintaining analog track quality that is better than tungsten light readers typically delivered.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

When Have I EVER hid my feelings?

While many have converted to red readers, it wasn't because of a belief in their superiority or desire to protect the environment. It was more to do with scare tactics and being told about cyan's immenent adoption. Do you care to look at the USL ads of the previous, say 3 years...if you believed them, we would have had cyan track years ago. The facts are, the red readers are in place because they were purchased with new machines. The converted soundheads are a small percentage of installed base of red readers.

I don't think you will find many exhibitors that enjoy paying a technician to change an LED over their own employees changing a light bulb (either analog BXMs or digital EPTs). When one looks at the cost to the exhibitor, the Red light reader is more expensive to buy and to keep. At least the IR LED lasted long and was stable.

In my opinion, the installed base of red readers had very little to do with consumer choice, it just is what is being done on new installations. If the cyan scare wasn't there, I doubt the red LED would have gone anywhere...it offers nothing but wasted money to those that buy them.

Steve

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"Old projectionists never die, they just changeover!"

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Ray Derrick
President/Chief Engineer
Panalogic Corporation Sydney, Australia
Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935

The cyan and magenta layers of KODAK VISION Color Print films are very fine grained and very sharp. Here is the granularity curve:
http://www.kodak.com/global/images/en/motion/products/lab/f010_0056ac.gif

Here is the Modulation Transfer Function (MTF) curve:
http://www.kodak.com/global/images/en/motion/products/lab/f010_0053ac.gif

Either/both of the cyan or magenta layers work well for dye tracks. But cyan was chosen because of the installed base of red LED readers, and the greater luminous efficiency of today's Red LEDs.

However, speaking as an operator at a six-screen theatre with DTS and Dolby Digital all around, I would have to say that we would enjoy greater benefits overall from eliminating the soundtrack redevelopment stage. Our print of 'Scooby Doo' has a splotch during the opening Warner Brothers tag that we'd rather not see. (I can also see the argument that errors such as this do not have to occur, although invariably they seem to).

It is exceedingly rare that we present any piece of film - film ads, trailers or features - in analog; the exception being some film ads which do not have a digital soundtrack.

In the UK, an informational film for exhibitors "Red Alert: The Movie" was available:
http://www.davidbyrne.plus.com/Films/RedAlert.html

Watch your film shipments for more information from distributors --- it's coming soon.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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