This is topic LED versus Exciter bulbs in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Erick Ojeda (Member # 216) on 11-17-1999, 07:06 PM:
Hi, I read in Film Journal magazine a few months back about soundtracks on films being changed to magenta, and then to Cyan. The writer of the article said that the reason for the transition to magenta before cyan is so that theater owners will be able to change their exciter bulbs to LED. He called this period, "the transition period for theater owners." At the theater I work at, we run Simplex XL projectors with exciter bulbs. Would the change of the soundtracks really affect us if we didn't make the change to LED? And if the change of the soundtracks doesn't really matter to change the exciter bulb to LED, what would be the advantage to changing to LED anyway? I would like to thank everyone asnwers my questions.
Erick Ojeda
Posted by Gordon McLeod (Member # 33) on 11-17-1999, 07:41 PM:
The magenta track can be read by both a led or an excitor
A cyan track will not reproduce with a excitor so if you wish to have optical sound you will have to have a red light source specifically red led
Posted by Erick Ojeda (Member # 216) on 11-17-1999, 07:56 PM:
Thank you Gordon for the reply. I currently have 4 simplex projectors to operate, and they all run with exciter bulbs. In your estimation, what would be the average cost to convert all four to red LED?
Posted by Ken Layton (Member # 133) on 11-17-1999, 08:38 PM:
ALL the theaters in my local area still have good old reliable exciter lamps. From what I've seen at many other theaters in western Washington State, only 30 percent have converted to reverse scan/led setups. That leaves 70 percent still running exciter lamps.
Posted by Mike Bianchi (Member # 271) on 11-17-1999, 08:39 PM:
If you are running Simplex XL's, which sound head head are you using?Kelmar makes a nice retro-fit conversion for the SH-1000 sound head for about $750 (plus installation).
I know Hadden Theatre Supply in Louisville is carrying it.
Posted by Erick Ojeda (Member # 216) on 11-17-1999, 08:55 PM:
Mike: To my recollection, we run SH 1000 soundheads. Right now, the theater I work at is getting renovated because we are under new ownership, so it is going to take some time to get the owners to upgrade some equipment. At $750.00 a pop plus installation, they might give me a hard time, but in time I will convince them after finding the best price I can find. What do you believe is the time frame before all films run with the Cyan soundtracks?
Posted by Scott Ribbens (Member # 180) on 11-18-1999, 12:02 AM:
Another option that you have is to go with the Ultra Stereo Jax Light. It is a direct exciter replacement. If the optics on your sound head are in good shape, you should get very good results, but if the optics are not in great shape you would be much better off with the Kelmar reverse scan up-grade. As I recall, they are about $500.00 list-plus installation. I have had good results with these, but you get better results with a change to a Kelmar reverse scan.As to a time frame on switch over to Cyan tracks, I couldn't say. Maybe John P. ,our man from Kodak, could chime in on this one 
.
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Scott
Posted by Kelsey Black (Member # 126) on 11-18-1999, 01:10 AM:
As I said in the other thread, I found that "the Story of Us" was printed with a cyan soundtrack (and a faded one at that) and it played just fine with exciter bulb illumination.
Posted by Brad Miller (Member # 2) on 11-18-1999, 01:48 AM:
Personally, the difference in crosstalk and frequency response is well worth the full led reverse scan upgrade! I wouldn't mess with the Jaxlite because at $500 vs. around $700...that doesn't make sense. I've used the Kelmars with excellent results and the Component Engineering are fantastic as well.I think John Pytlak has been out of the office on a "China" program. If memory serves, he will be back today and hopefully can give us a better guesstimate on the cyan conversion date!
Posted by Aaron Mehocic (Member # 15) on 11-18-1999, 10:48 AM:
To my understanding, the change in tracks is due to hit on a mass scale after the first of the year (2000). I was told this last February by our technician. As for the reverse scan readers, Kelmar has the best. At our nine plex, we are running four of these, each in our digital houses. I was told the stereo houses will be converted after the new year. I'll believe that when I see it.
Posted by Gordon McLeod (Member # 33) on 11-18-1999, 04:43 PM:
A cyan track wikll definatly not reproduce with an excitor lamp all you hear is hiss with a low level soundtrack. I have tested it with cyan test reel that I had printed
The reason for conversion to cyan is to eliminate the residual silver in the soundtrack and the reduction of lab work that requires reprocessing just the soundtrack are with a very caustic chemical
A lot of prints get damaged in just that operation and are scrapped
I ahve had also good luck with the laser lens but getting even illumiation is a bitch of a jobThe conversion to cyan was planned to occur when 80% of new theatre (IE large circuits) had red light sources. That has been reached since no new machine doesn't have a red light source
Posted by Jeff Stricker (Member # 224) on 11-18-1999, 07:01 PM:
Can a super bright red LED be used as the exciter light source replacing the bulb and NOT as a reverse scan light source? Most of what I have read indicates that LED's are only used in reverse scan applications.
Posted by Aaron Sisemore (Member # 145) on 11-19-1999, 01:03 AM:
Jeff:That is exactly the principle used by the JAXlight, they take a high intensity LED array and mount it onto a unit with twist-lock base that fits a standard exciter lamp assembly perfectly.
Aaron
Posted by Steve Guttag (Member # 268) on 11-19-1999, 08:53 AM:
Ok...as to the conversion to Cyan based soundtracks (I am on the SMPTE committee that covers this)....Gordon was mistaken...the conversion is set to take place when 80% of the INDUSTRY HAS CONVERTED to red LED readers (that includeds the installed base). That number is less than 50% at this time (I believe it was near 40% at the last meeting) and the current estimates for when the magic 80% number is achieved is still years away. Heck, E-Cinema may take over before the cyan track!Now as to the comment that Kelmar's basement readers are the best....just where did someone get that data? Kelmar makes a good product but it would be hard to say that they are definatively "the best". Their LED mount is fixed and dependant on the precision of the original milling of the soundhead casting and depending on vintage, is all over the place for Century and Simplex. I can generally get a better alignment out of a Component Engineering reader and have heard that Kinoton's basement reader is tough to beat (though I haven't used that one yet).
Oh, another nice thing about CE readers...you don't have to cut up your Century sound head...everything fits right out of the box.
Steve
Posted by Gordon McLeod (Member # 33) on 11-19-1999, 06:00 PM:
One of the Canadian Labs has stated they plan to cease silver enhanced tracks when 80% of new theatres are led based. And that was where I heard that info. Also at Showeast last year Technicolor US was planning on the same timeframe
Posted by Stephen Winner (Member # 8) on 11-19-1999, 08:33 PM:
On our simplex XL's we have a small mirror that diverts some of the light from the Peerless Magnarc's into the sound head. How would it affect operation to install a red gel somewhere in the light's path so that we can play the cyan tracks without converting? Converting this setup would be a nightmare! This can be done easily from the looks of the soundhead, and save plenty of trouble of trying to convert these things to LED
Posted by Jim Alexander (Member # 226) on 11-19-1999, 10:36 PM:
Being a relatively new theatre owner (who had no benefit of background information or manuals to go by) I've been forced to learn as I go. Many times I've gotten "blind-sided" by left field problems. The latest is the change over from Exciter to LED (living in the "sticks" sometimes means not getting up to date information. What is the story here and am I up the creek on this one.We run Century-C projectors with Exciter Lamb mono sound pick-ups. Am I going to have to convert? When and where did this all come about?
Someone plase help?@#@??!??
Posted by Lance C. McFetridge (Member # 95) on 11-20-1999, 08:05 AM:
I have been reading about the switch to cyan sound tracks and the lack of theatres with the reverse scan capabilities with some interest. If in fact the industry is dragging it's feet to conversion, and by all estimates it is somewhere around $1k per projector, how will the industry ever switch to digital projection? Because I know if it digital is mandated, the toes of my shoes will be worn out.
lance
Posted by Gordon McLeod (Member # 33) on 11-20-1999, 03:13 PM:
What make of soundhead diverts the magnarc light to read the sound?
Posted by Greg Mueller (Member # 17) on 11-20-1999, 08:10 PM:
One of the problems with just replacing the incandescent bulb with an LED is that the exciter light (incandescent) system relies a great deal upon infrared, which the incandescent has plenty of. The led has no infrared so the detector and the led are working at different frequencies (kind of). Because of this "mismatch" you get less gain and more hum (noise). The reverse scan units are tuned to read at the same "wavelength" as the LEDs so it works with a minimum of "noise" and "hum" . Also, I think if you compare prices, CE will beat out Kelmar.
Posted by Greg Mueller (Member # 17) on 11-20-1999, 08:20 PM:
Oh yah, The analog sound track up untill this point in time was coated with silver (something or other) which blocked the passage of the infrared and so the system worked. The shadow cast on the pickup was infrared free, because of the silver goop. But, when they convert to the new sound tracks the silver goop will go away and if you shine infrared on it it will pass right on through producing no shadow and the incandescent system will not work at all. The LEDs don't have this infrared problem so they will work.
Posted by Scott Ribbens (Member # 180) on 11-20-1999, 10:39 PM:
Which brings us to those theatres that have the infra-red LEDs. You can replace these with visible red LEDs. The companies are now making these replacement LEDs.------------------
Scott
Posted by Bill Purdy (Member # 202) on 11-22-1999, 11:57 AM:
If the Infra Red readers you have are Component Engineering's, please look on our website <www.componentengineering.com> for information. A listing of available versions can be found under "Price Lists" and there are a couple of instructional things under "Technical Bulletins". Unfortunately it is a little more complicated than we all might wish because the 660 nm LED's have turned out to be different than what we originally expected. We had to do a much better job of heat management and we felt the need to make a safer power supply. You can use the old power supplies with the new LED's but there are a couple of easy mods that are needed for the protection of the LED's. If you are converting a full Analog/Digital version it is not quite so easy, but kits are available.If you have more questions, please call.
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Bill Purdy
Comonent Engineering
Posted by John Pytlak (Member # 331) on 11-23-1999, 09:05 AM:
Kodak's web site has a complete description of the industry plan to convert to silverless (cyan dye) analog soundtracks:
http://www.kodak.com/US/en/motion/support/sound/index.shtml Dolby's web site also has information:
http://www.dolby.com
Many labs and distributors have already converted to the "high-magenta" (magenta dye + silver) soundtracks, which are compatible with BOTH red LED and white light (tungsten light bulb) soundheads. The "high magenta" tracks are more compatible with both readers than the old magenta+cyan+silver tracks. The first major release with "high magenta" tracks was "You've Got Mail".
The proposed cyan dye tracks are NOT compatible with white light readers, and would have very poor signal-to-noise on these old readers. Conversion to cyan dye tracks will not occur until the vast majority of theatres are using red LED readers, probably in 2001 at the earliest. Almost all new sound readers use red LEDs for the many advantages they offer, but older soundheads need to be retrofitted.
Digital sound is NOT affected by this change. None of the three digital sound systems require silver to be left in the film.
The industry conversion to cyan dye tracks is motivated by environmental responsibility --- eliminating the silver redevelopment step in the print processing gets rid of a very caustic chemical and one of the major sources of waste in lab operations. With cyan dye tracks, almost all the silver in the film will be totally recovered by the labs, helping the environment when old prints are scrapped or recycled.
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John Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Research Labs, Building 69, Room 7419
Eastman Kodak Company
Rochester, NY 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243