[tig] Cyan Dye Tracks on Telecines

john.pytlak at kodak.com john.pytlak
Fri Oct 1 16:50:17 BST 2004

Here is a link to UltraStereo Inc., a company that has developed a line of 
red LED sources that can be retrofit to existing tungsten light readers:


Other companies making Red LED sound readers are listed on the 
http://www.dyetracks.org website .

(signed by:)
John P. Pytlak
Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, New York 14650-1922  USA
Telephone: +1 585 477 5325
Cell: +1 585 781 4036
Fax: +1 585 722 7243
e-mail: john.pytlak at kodak.com
website: http://www.kodak.com/go/motion

Dave Corbitt <david.corbitt at verizon.net>
Sent by: tig-admin at tig.colorist.org
09/29/2004 07:27 PM

        To:     Rob Lingelbach <rob at calarts.edu>, Telecine Internet Group 
<tig at colorist.org>
        Subject:        Re: [tig] Cyan Dye Tracks

thanks to Flying Spot Film Transfer for supporting the TIG.
Re: utilizing Aaton or Evertz type scanners for Cyan auido tracks. 
The whole question of scanning Cyan Dye tracks can be more simply 
addressed by replacing the tungsten halogen bulb in the optical 
exciter assembly with a bright strip of LEDs of similar light 
emitting surface area as the glowing filament but limited to 
approximately 660 nm wavelength. This would be much simpler and 
easier to accomplish than all these complex schemes of reinventing 
the whole assembly. Most of the optical audio sensor would not change 
and there would be no need for it to change. The only different 
characteristic needed to properly scan Cyan tracks is to complement 
the Cyan Dye which absorbs visible Red (Cyan is "minus Red" in 
subtractive color nomenclature) by providing a Red light source of 
suitable wavelength. Contrast of the tracks is then optimized. And 
the existing sensors are all in the right place for traditional sync 
sound. On a Spirit the Keykode reader is way before the image gate. 
Optical audio pickups are always after the gate to complement 
industry practice for many decades. To delay the audio from a sensor 
placed before the gate, you would have to add the number of frames 
before the gate, and the number of frames after the gate, to delay 
the audio sufficiently for sync sound. So Cintel and Thomson, how 
about it? Can you come up with an alternate optical audio light 
source upgrade for our expensive machines to get us all working with 
these kinds of tracks? It shouldn't be that hard to do to replace a 
lightbulb with an LED array. Those ultra bright Red LEDs used in some 
new auto tail lights and traffic signals would probably do the trick 
quite nicely.

Dave Corbitt
Post Logic NY

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