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Author Topic: Pulse lamps........ William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 10-14-2003 12:13 AM                        quote: It wouldn't surprise me if they did claim that, but there were shutterless projectors going back at least as far as the '20s. There was a flashing-light design going farther back than that, pre-dating projection. Anshutz' Electrical Tachyscope used flashes of light from pulsing a Geissler tube (a tube filled with gas caused to glow when excited by high voltage via an induction coil). The Tachyscope was later developed into a projecting model. http://www.acmi.net.au/AIC/ANSCHUTZ_E_TACH.html  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 10-14-2003 12:15 AM                        What would the advantage of such a pulse light source be over a simple mechanical shutter? I mean, the mechanical shutter is an efficient design that works well (if it ain't broke...etc.) If the pulse light was, say, a colder light that delivered less heat to the film, or if it was brighter than a steady light source, then there would be a reason to entertain its use. But unless I am missing something, I don't see what advantage the pulse light was supposed to bring to the existing system. It had a short life, so much so they had to basically build two in one envelope, it had produced less light than a carbon arc source, it had terrible color temperature and it needed to be water-cooled, and to top it all off, it produced a double ghost!! Good grief, could there be any worse idea just to eliminate a perfectly good mechanical shutter design? It's almost as bad an idea as installing a $170,000 video projector that produces an inferior picture instead of spending $20,000 for a 35mm film projector. Frank  |  IP: Logged Bernard Tonks Jedi Master Film Handler Posts: 619 From: Cranleigh, Surrey, England Registered: Apr 2001 posted 10-14-2003 04:38 AM                     quote: I've never seen a set-up using them, but I have seen pictures. I seem to remember that Bernard Tonks had experience of them. There is some information on the Philips Pulse light in the 2001 Film Handler's Forum, Philips/Norelco FP20. Regret unable to link this thread To quote from a manual, the SSP.800 gas discharge lamp consists of a quartz tube only 3-1/8” (80mm long), 72 impulses per second or three impulses per frame, there of course being no flicker shutter. The average life of lamp was 33 hours under full load. The average bulb life at Bayswater was between 60-70 hours, and many did upto 115 hours. The size of scope screen was 36’. This was in the year 1960, and the lamps were water cooled.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 10-14-2003 06:50 AM                     Thank you Bernard, I thought it was you. I seem to remember you had a photograph of a remote control console for the projectors installed in the auditorium. How did you find the light output on a screen that size? Was it adequate? Was it equal to what they replaced, Peerless arcs, if I remember correctly? Also, did you find the colour satisfactory? I find it quite surprising that this idea hasn't been tried again since. Just about everything seems to get re-invented every few years, and discharge lamp technology has moved on a long way in almost fifty years. I suppose the advantages of a pulsed lamp over a conventional xenon are less than those over a carbon arc, so there is less incentive to develop one today. The top picture on Long run projector shows a long run projector which looks rather similar to the Fedi one in concept, though rather more compact. It seems to be based on an FP-20, with oversized spool boxes, still in the same rather odd shape as the smaller philips ones. Is the lamphouse on this projector one of the pulsed ones?  |  IP: Logged Warren Smyth Expert Film Handler Posts: 158 From: Auckland ,New Zealand Registered: Aug 2003 posted 10-14-2003 07:05 AM                     Stephen quote: How widely used were these things? Well a couple of pair found their way over this side of the world I believe in the late fifties. One pair at the Plaza in Auckland didn't last more than a few months - poor light and just preceeded the instalation of DP70s for 70mm. They were transfered to a smaller theatre where they ran well into the seventies. I saw the result there on a smaller screen. Again low light with a blue hue. The other pair were in Queenstown and represented the first automated plant in the country. This aspect is probably what the pulse light will be remembered for. It provided an early means of automation using two projectors, 6,000ft reels and automatic change-over. I think the idea was to enable the manager owner to carry out the duties of projectionist and manager. This was before the days of multiple screens. Automation therefore had a different meaning in those days, but with the carbon arc being the only alternative form of light source, this Philips installation was pretty revolutionary. I believe the system ran sucessfully in the MODERATE sized theatre for quite a while.  |  IP: Logged Jeff Taylor Jedi Master Film Handler Posts: 601 From: Chatham, NJ/East Hampton, NY Registered: Apr 2000 posted 10-14-2003 10:57 AM                     FWIW: The military used the pulse xenon approach for their xenon retrofit kit for the JAN 16's. If memory serves, I believe it was a Hanovia lamp.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 10-14-2003 11:57 AM                    Of course if you had an actual strobe rather than a pulsating arc you could dispense with intermittent film motion as well. But it would have to be a heck of a bright strobe to register in 1/100,000 sec. (or whatever it is) what the eye normally integrates over 2 x 1/96 second flashes. I wonder how it would look though. Aren't there lab inspection machines like that?  |  IP: Logged Ken McFall Jedi Master Film Handler Posts: 615 From: Haringey, London. Registered: Apr 2001 posted 10-14-2003 12:08 PM                     If you look on the fly wheel on the back of the intermittent on some older FP20 projectors you will see the notches that were cut out. A sensor was mounted to see these and they were used to trigger the pulses, three per frame which, giving 72 fps, it apparently gave a very good flicker free image. I worked at a cinema that had a very early installation, the water cooling system was still there. From what I was told the system worked very well giving a very even light on screen. The momentary blank as the lamps changed over was not really a problem. However the water filters, the lamps were surrounded by water, apparently needed constant checking.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 10-14-2003 12:14 PM                     Isn't that basically what the Edison Kinetoscope did? Ok, not with a strobe, but a continuously moving film and a shutter with just a very narrow slit in it.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 10-14-2003 04:06 PM                        If you pulsed the lamp at 24 fps, how did you avoid seeing the flicker? Most people are very sensitive to flicker when the rate is much below 48Hz.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-14-2003 07:40 PM                     There was a telecine system called syncrolite that used a strobe lamp  |  IP: Logged Dave Callaghan Film Handler Posts: 60 From: Toronto, Ontario, Canada Registered: Jan 2003 posted 10-15-2003 12:29 AM                     Pulse lights were installed in at least 3 booths in Toronto that I am aware of - the Ontario Science Centre Great Hall, the Universal screening room, and at an independent cinema, Cinecity. One of the problems that I understand made them difficult to use in North America was that they were designed to run at 50 hz. For North America, the pulsator had to convert 60 hz to 50 hz, which caused problems.  |  IP: Logged Bernard Tonks Jedi Master Film Handler Posts: 619 From: Cranleigh, Surrey, England Registered: Apr 2001 posted 10-15-2003 06:41 AM                     Stephen wrote, quote: How did you find the light output on a screen that size? Was it adequate? Was it equal to what they replaced, Peerless arcs, if I remember correctly? Also, did you find the colour satisfactory? It was perfectly adequate for 1.75 wide screen but not for scope with Kalee varamorph heavy light eaters. As I mentioned before, Bausch & Lomb anamorphics should have been used. Without doubt the Peerless carbon arcs gave the better white light. Technicolor prints were only just about satisfactory in my opinion. I do remember a cold slight blue hue on B+W films, which many were in those days (1960). The screen I believe was a new Purlux surface. The picture on the Philips Long run projector is the model with Pulse lamp.  |  IP: Logged

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