my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Looking for IR spectrum data for different makes of bulbs.

Author Topic: Looking for IR spectrum data for different makes of bulbs. Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 07-02-2007 01:45 PM                     I'm interested in comparing infrared spectrum output from different makes of bulbs. Anyone know if this data is readily available?  |  IP: Logged Michael Moore Expert Film Handler Posts: 188 From: Dover, DE / USA Registered: Jun 2006 posted 07-02-2007 02:08 PM                        I've asked this question before and all I got from people here is nothing, I can measure it because I have an avaspec 211c with fiber optics. I have not done so because I only have one bulb and none for comparisons. I can do it if you want but it is going to take me till next month because I have my lamp house down. I have an ASL bulb and that is it. What wave lengths are you interested in? if you check out http://en.wikipedia.org/wiki/Xenon_arc_lamp there is a discussion about the IR spectrum I believe in the 800-950 range. I never looked into the manufactures of the bulbs but I'm sure they have the data. Mike  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 07-02-2007 04:33 PM                     Why is this data interesting? Osram's Technology and Applications guide has a graph on p.12 for "a typical XBO lamp" versus a black-body radiator. (For some reason the graph doesn't show up in the copy in the Manuals section on Film-Tech...) --jhawk [ 07-04-2007, 11:12 AM: Message edited by: John Hawkinson ]  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 07-02-2007 06:10 PM                     Having data about the IR spectrum would help me understand which bulbs generate more heat or less heat. Ideally I would like to buy a bulb which provides a lot of usable light and the smallest possible amount of IR.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 07-04-2007 09:30 AM                        Frankly, I suspect that lamps of a given power produce very similar levels of Infrared energy. A Xenon arc's spectral output is relatively constant, and unless some sort of proprietary filter were used, I doubt lamps would be much different from each other.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 07-07-2007 01:02 AM                     Thanks John, that's the kind of information I was looking for. A 4500 watt Perkin Elmer bulb was installed in a super highlight II which had previously been using a Christie 4000 watt. The theatre ran the show and burnt each frame to a crisp. When I interveined, I installed a heat filter lens in the snood. I adjusted the bulb amperage to 80% of max amperage, even still the film was very hot coming out of the film gate. I ended up defocusing the bulb for a darker picture and cooler film. I was suspecting that this Perkin Elmer bulb somehow generated more heat than the Christie, so I thought I would try and analyze the IR spectrums to compare heat output to see if my suspicion was true or false.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 07-07-2007 08:45 AM                     I beleive there is a fair bit of difference in the IR area between manufacturers I have notice that with identical light distribution the PE/ASL lamps produce a measurable hotter projector head (same light level and distribution same cooling ) I would suspect it is in the doping of the electrodes or the type of quartz used?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-07-2007 09:05 AM                     Hmmmm...I've never noticed this before but I had never been looking either. You might try asking the people at ASL...they are some of the nicest people to talk to and they genuinely seem interested in making the lamps as good as possible. Steve  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 07-07-2007 07:24 PM                        The total mass of the anode and cathode electrodes could have a small effect on the amount of IR (they get red hot), but the energy from the xenon plasma (arc) would predominate the output spectrum.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-07-2007 10:19 PM                     I have found that different lamp designs produce more/less light in different reflector/lens combinations. It isn't all about wattage. Some lamps work better with some reflectors than others.  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.