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Author Topic: Dichroic Filter or Cold Reflector? Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 03-12-2003 06:57 PM                        I'm setting up to run some 3D and the instructions I have say...."Be certain that your lamphouse has "cold" reflectors or dichroic filters installed".... I have a Super Lume-X lamphouse. Do they have "Cold Reflectors"??? The reflector is new. There are no filters  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 03-12-2003 07:02 PM                        It is if it came from Strong. If it's an Ultra Flat re-do, it isn't.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-12-2003 07:18 PM                     I concur with Jack.  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 03-12-2003 07:53 PM                        How do you tell? Pics of the lamphouse in question at http://www.muellersatomics.com/alignotron.htm  |  IP: Logged Sam Hunter Jedi Master Film Handler Posts: 779 From: West Monroe, LA, USA Registered: Jan 2002 posted 03-12-2003 07:58 PM                     Cool reading Greg. I don't have an answer but I have a question. Where does one find an Align-O-Tron? I performed a search and found my answer. I forgot that Greg invented the device. [ 03-12-2003, 10:15 PM: Message edited by: Sam Hunter ]  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 03-12-2003 08:00 PM                     As seen from your photos you have a "cold reflector" due to the gold color of the reflective surface....as long as you do not have gold flecking near the arc ball position of the reflector, it should work well.....a dichoric heat filter in the douser area, angled properly, would give you more insurance. Richard Fowler Kinoton America Inc.  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 03-12-2003 08:08 PM                    Yes you should be able to use that type of reflector with no problems. We used that type years ago for 3D. Now the dichroic filters may be the glass reflector type where the ulta violet light passes thru the reflector to prevent loss of light output. It could be a filter placed in front of the light that magnifies the light output I have seen these but was never sure what they were called.  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-12-2003 08:33 PM                  Greg: Yes, that is a "cold" reflector. Are you using a single or dual projector setup for 3D? If duals, make sure that the reflector color temperatures are the same. If not, it would look OK after awhile, but would be a total PITA when the show is over and you try to look at things without the glasses! It's always best to match them as if it was a "change-over" theatre. >>> Phil  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 03-12-2003 09:42 PM                        It's a single projector. Side by Side anamorphic. I've got the original lens for projecting and a Silver Screen on the way from the great white north (MDI) Sam send me a note off line  |  IP: Logged Fred Georges Master Film Handler Posts: 257 From: Lombard, IL, USA Registered: Jun 2000 posted 03-12-2003 09:51 PM                     Dear Greg, You've got a cold mirror but, at 1K it wouldn't make any difference. Those StereoVision instructions really only start mattering at 2K & above and it's to protect the polarizers from burn up from the UV. The Marks Polarator & StereoVision Mirror box "fit" the AAII quite well for over/under. If you're doing side by side "House of Wax" etc. You can rig a much superior lens set up then the Stereovision all in one with those old B&L cokebottle Scope lenses they use. If you do it right you'll want to collect nothing but 3D. It's that much fun.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-13-2003 07:07 AM                        The dichroic coating on the reflector is there to remove the INFRARED (heat) energy from the light output of the lamphouse, usually with a "cut" for wavelengths greater than about 750 nanometres. As Richard notes, an additional dichroic heat filter that mounts in the beam and reflects the IR to a heatsink is added insurance for larger lamps. It's also a good idea to remove the ULTRAVIOLET energy from the light, as it can cause dye fading after thousands of runs. Century used to have a "UVIR" filter that mounted behind the shutter. Here are some tutorials on dichroic interference filters: http://www.ocli.com/pdf_files/products/dichroic_coatings_uv_vis_apps.pdf http://www.ocli.com/pdf_files/products/gen_info_infrared_filters.pdf http://www.spie.org/web/courses/videos/vid97ose.html http://www.broadwaypress.com/PDFs/LTSpdfs/LTSchpt09.pdf  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-13-2003 09:13 AM                     Those small 1K's can still ruin polarizers just as badly as bigger lamps Do not project white light through the system for any extended length of time  |  IP: Logged Fred Georges Master Film Handler Posts: 257 From: Lombard, IL, USA Registered: Jun 2000 posted 03-13-2003 03:40 PM                     Whoops! Got my UV's & IR's mixed (Too much Bourbon). Thanks John for the correction. Assuming that this is the StereoVision one piece with anamorphic attachment. The polarizers are sandwiched between the adjustable prime & the Scope lens. As such the polarizers are much more prone to Heat damage then the front loaded mirror box attachments. I've never experienced Heat damage to the Mirror box type polarizers at anything under 2K but, yes I never run the lamp with a clear gate through them.  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 03-13-2003 03:49 PM                        It's the backup lens "combiner" from StereoVision. One thing that is interesting is how to mount the StereoVision/backup lens separate from the anamorphic. Both have to be adjustable independently. I'm thinking a long 4" (dia) adapter, with setscrews at either end, since it has to go into a lens collar on the DP70 anyway  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-13-2003 10:17 PM                     The original split lens had a thumb nut that allowed the back split lens section to be rotated independently of the anamorph is the black tube was what the lens mount clamped in place Also there is a set of bristol splines on the side that can modify the convergance if necassary  |  IP: Logged

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