This is topic Cyan tracks - laser upgrades in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Peter Hall (Member # 695) on 02-13-2002, 12:31 PM:
 
We've just started installing a new type of laser upgrades to Kinoton / Century / Cinemec kit. (have a look - www.fproj.com/cyan). We've found these to be great - especially for Kinoton where stray light is an issue. The laser barrel replaces the optical lens assy - i.e. you're not trying to stick an already small slit of light thru a 30 year old lens and slit. Tests with Cat556 (566 ? - cant remember) show less than 0.5dB loss at either end, plus there is a slit width adjustment (a la the cinemecannica lens).

Unit uses any existing supply (4V Ac or DC to 12V - would like to find an exciter supply that can't deliver that !) and sets up with ease - gain is 4 divns from the minimum on a CP500 and HF gain (slit loss boost) is near minimum.

Units have been in the field for years without prob - any comments on longevity of these would be welcomed.

Are there many lasers in the States ? Should I bring a sample to ShoWest ?

(PS - no comments about half finished web site please - we know but prioritise looking after our existing customers over spending weeks at the keyboard )!

Peter

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Posted by John Hawkinson (Member # 1135) on 02-13-2002, 05:08 PM:
 
Looks like the URL is wrong, and should be http://www.fproj.com/cyan.htm.

--jhawk


 


Posted by Mark Gulbrandsen (Member # 72) on 02-13-2002, 05:22 PM:
 
What is the crosstalk and distortion spec? Also what is the rated life of the laser diode(in reality)?
Mark @ GTS
 
Posted by Ray Derrick (Member # 1001) on 02-14-2002, 05:39 AM:
 
Peter, with earlier laser diodes that we have seen, the emitted light consists of a large number of individual beams. If you shine the laser onto a white surface without the slit lens and observe the light pool with a magnifier, you will see a large number of tiny red dots, rather than an even pool of light. This produces noise which is modulated by the audio on the soundtrack, and is particularly evident under dialogue.

With the units that you are installing, has this problem been overcome and if so, how?

Mark, laser diodes do result in very low crosstalk, at least as good as a reverse scan system. This is because all the light rays emitted from the diode are parallel, so there is no light cross-over in the region between the film surface and the solar cell, as there is with other light sources. Also the light intensity across the usable area of a laser diode seems to be about as consistent as it is with a red LED, so distortion appears to be pretty much the same as with an LED.


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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


 


Posted by Ray Derrick (Member # 1001) on 02-16-2002, 05:07 AM:
 
Are you there Peter?

Would you like an easier question?


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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
 


Posted by Peter Hall (Member # 695) on 02-16-2002, 07:09 AM:
 
HI -

Have had a look at one of these re your comments Ray. Stripped the unit, projected on a a large wall a long way away and light appears to be clean. Compared this to an ASL unit and the difference was obvoius.

Crosstalk is immeasurable, as it should be

Re distortion, whilst we've not metered it ourselves we have done a lot of A / B comparisms. Using the Dolby Jiffy film the sweeps are clean (audibly, looked at on the scope, also plotting L vs R) and sound less distorted than the Cinemec basement reader kit (just happened to be one in the same building - NO disrespect inteneded to CInemecannica).

Any of these in Oz ?

Cheers

Peter


 


Posted by Mark Gulbrandsen (Member # 72) on 02-16-2002, 09:54 AM:
 
Its a good idea if it really works as U claim it does. The thing I don't like about it and the German unit is that you are still stuck with the dang tiny stereo cell hanging out there in space just waiting to get clipped off by passing film fold or tape. The Stereo cells are also far more vulnerable to being jared out of alignment as well. I'll stick to the reverse scan units for now anyway as they seem to hold up really well to abusive environments. Also if I convert your price over to US dollars yours costs more than a reverse scan kit. Probably not so in your country where the reverse scan kit is probably double what you sell the laser setup for.
Mark @ GTS
 
Posted by Gordon McLeod (Member # 33) on 02-16-2002, 10:20 AM:
 
The ernamann sound head uses a light pipe back to the cell
You should test the cross mod on the unit for distortion
 
Posted by Ray Derrick (Member # 1001) on 02-16-2002, 04:21 PM:
 
Mark, I totally agree with you on the vulnerability of the dangling solar cell. However lasers do offer the promise of some real benefits over reverse scan systems, such as high output level without the need for a localised preamp and it would seem they do not suffer from falling light output the way the superbright red LEDs do.

Peter, I know Hoyts here have been installing Walter Voigt's lasers on their Kinoton machines and are reporting very good results. Who is the manufacturer of the units that you are installing? I would be very interested in taking a look at one.

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


Posted by Steve Guttag (Member # 268) on 02-17-2002, 01:56 AM:
 
Bay Area Cinema Products is claiming to have their LEDs not fading so much and USL/BACP have or are bringing out a rectangular LED claimed to also work well with more even light than the current Dolby LED.

Steve
 


Posted by Peter Hall (Member # 695) on 02-17-2002, 04:03 AM:
 
I agree that the ideal solution is to fit a manufacturer's (or good third party) retrofit kit. Here most of our kit is Cinemec or Kinoton - the Kinoton reverse scan kits are prohibitavly expensive for a house not looking at going to Digital. Even the Cinemec (@ something like GBP£700 to £1000 aren't cheap.

We initially installed JaxLites on Kinotons but found noise, hassle (pre amp, 2 new PSU etc) and stray light to be problems. Don't stand next to projector 6A at an unnamed West End cinema with a white coat on !

We've left the exciter lamp holders intact in all machines we've done, allowing in an emergency the operator to refit the exciter lamp and lens (OK, a bit of guesswork but there's at lease a chance he or she will get the thing working) in the event of a laser failre.

Cell vunerability neednt be the problem it used to with a laser. Sure, a wraparound is going to write off a Cinemec cell regardless of what you do but because of the flexibility of location of the lasers / cells the cell and bracket can be far further back (as much as the cell allows anyway) thus avoiding snagging the cell.

Price wise, as I said we started using these units as a solution for Kinotons, although they seem to to work our well for Century etc. With these kits listing at £GBP366. i.e around $USD512 I thought they were one of the cheapest on the market - if anyone has a better solution for Kinoton my chequebook is open. Retrofit kits here aren't as easy as in the states, as most of our older machines are Westars (2001 i.e. Century) with just enough differences to make installing a Component Engineering / Kelmar / other third party kit a pain.

Yes, BACP's kits use the lowest LED current. We've looked at these and they seem very good however they are caught in a "no mans land" between cheap effective upgrades (i.e. the lasers) or the real McCoy manufacturer's kit.

What is the rollout of cyan tracks in the US ? Here all but one major chain has finished their upgrades, and this chain (using our lasers no less for Century sites) will be complete in a month or 2. Have there been many cyan releases ..

Cheers

Peter
 


Posted by Leo Enticknap (Member # 534) on 02-18-2002, 03:23 AM:
 
quote:
Sure, a wraparound is going to write off a Cinemec cell regardless of what you do...

Sorry if this is a bit off-topic, but I've often thought that one way of preventing polyester film from causing damage like this would be to revive a piece of technology that was last used in the days of nitrate, namely a device which automatically cuts the film in the event of it jamming.

In nitrate-era projectors these were situated in the spoolboxes - in the event of a film path jam whilst the lamp was lit, these two cutters would slice the film, with the result that if it did ignite, only the 10 feet or so actually in the projector mechanism would burn. The rest of the reel would be safely sealed inside the two magazines.

The way this could be adapted to protect the soundhead in the event of a platter wrap would be to mount a motion sensor on the platter's feed unit (like the sensors on a TA-10 automation reader) and a cutter unit near the top of the platter tower, just where the film is angled away from the platter towards the projector.

If the sensor detected the speed of the film passing through the feed unit starting to drop significantly below 1.5 feet per second and at a rapidly accelerating rate, the cutter would instantly slice the film at the same time as the platter and projector motors were stoppped. That would have the following advantages:


Of course there is the problem that for every false alarm, each print would acquire an unnecessary tape join. But in the event of a genuine wrap, you're guaranteed to lose at least 3-4 feet from the print anyway, even if only a small quantity of film gets mangled in the vicinity of the feed unit. And I'm sure it would be possible to design the cutter unit so that it only cut through the frame line (although the optics and electronics needed to detect this would probably add a lot to the cost), meaning that in the case of a 1:1.85 print, if the join were remade carefully it would be totally invisible on the screen.

Given the amount of money such a system has the potential to save in repairs to feed units, rollers and soundhead assemblies, I'm surprised that no-one (to my knowledge) has developed and marketed one.
 


Posted by Ray Derrick (Member # 1001) on 02-18-2002, 07:03 AM:
 
That seems like a bute force solution Leo. (I assume you already have failsafe switching for this purpose and you are referring to the damage done during the time lag due to the momentum of the projector motor as it slows to a stop). So how about a gentler solution. Why not have a spring loaded system on the platter feed out so if the film jams, the spring allows the film path to "stretch" while the motor comes to a halt. This could be done in a variety of ways, even hydraulically. Now there's an idea for you Bill Purdy, just send me the royalty cheques.


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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


 


Posted by Leo Enticknap (Member # 534) on 02-18-2002, 07:41 AM:
 
quote:
I assume you already have failsafe switching for this purpose and you are referring to the damage done during the time lag due to the momentum of the projector motor as it slows to a stop...

None of the 'wrap detector' devices attached to platters I've seen have even been activated until a certain amount of pressure has already built up (indeed, they are activated by a build-up of pressure through the feed unit rather than detecting a reduction in the speed of film movement) and as you say, the motor wind-down time then makes the situation worse.

A spring-loaded system whereby the platter maintains a 'buffer' of excess film that would be fed out to buy time in the event of a wrap shutdown could work. However, in all the systems I've seen it would need to hold at least 10 feet of film and would depend on being activated before any pressure had built up between the feed unit and the projector's entry sprocket (but there again, so would a cutter).


 


Posted by John Walsh (Member # 168) on 02-18-2002, 09:31 AM:
 
Xetron has a wrap-detector that also has rollers on a sliding track. When the tension gets too high, a roller assembly get pulled, activating a switch. The roller assembly continues as the projector motor winds down.

It will "hold" about 6ft of film, enough for our Simplexes to run down but not pull any angled rollers out of position.
 


Posted by Ray Derrick (Member # 1001) on 02-18-2002, 09:35 AM:
 
So platters could be fitted with a yo-yo on the payout side as well as on the takeup. The yo-yo would normally be held fully extended unless the fail safe detected excessive tension (or slowing film movement) from the platter payout head, in which case it would release the yo-yo.

Could be expensive!


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


Posted by Frank Angel (Member # 248) on 02-18-2002, 10:58 AM:
 
Yah, but guys, if these failsafe devices were installed on all platters, then we wouldn't have all those tasty stories about estar film pulling over projectors and platters. Sometimes I wonder what was going through the projectionist mind a the moment he heard a noise and turned around only to look down the lenght of the booth to actually see his projector tipping over.

Our booth is 5 stories above the orchestra floor. We have no elevator so the first thing I did was rig a wench in the hang cieling. It has a double hook that lowers to the orchestra floor below on aircraft cable. THe cans are attached to the hooks via the handles and then raised to the booth level and pulled through the large followspot window. Once as I raised a print (in TES's famous orange cans), one of the latches gave way, the can opened and as I watched from the window, I saw four reels of film fly out of the can, film unfurling down to the seats below. I recalls the one thought that went through my mind, right after "Holy s**t," was the almost beautiful ballet quality of the reels flying through the air and the 3D effect of them falling 5 stories. I imagine seeing a projector or a platter getting pulled over might evoke similar thoughts -- especially the "Holy S**t."
 


Posted by John Pytlak (Member # 331) on 02-18-2002, 12:50 PM:
 
Kelmar had a "Chopper Plus" failsafe mechanism that cut polyester prints cleanly in the event of tension buildup between the platter and projector:
http://www.kodak.com/country/US/en/motion/newsletters/reel/may97/fail-safe.shtml

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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: 585-477-5325 Cell: 716-781-4036 Fax: 585-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
 






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