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Author Topic: Dark Picture Joe Morris Film Handler Posts: 35 From: Papillion, NE, USA Registered: Jan 2003 posted 03-05-2003 04:20 PM                     I have a nice shadow at the bottom of my screen. I had to change the bulb out due to the bulb being bad. The screen was dark along the bottom before i changed the bulb, and it is still dark along the bottom. The shadow goes completely along the bottom of the screen and extends about 6-8 inches into my picture. any ideas?  |  IP: Logged Matthew Nock Film Handler Posts: 82 From: Bairnsdale, Victoria, Australia Registered: Jan 2003 posted 03-05-2003 04:35 PM                     Have you adjusted the vertical alignment of the bulb since replacing it? it sounds as tho this isnt the problem tho because the shadow is straight across the bottom.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 03-05-2003 04:54 PM                     Take the lens out or open the turret and project a white beam of light onto the screen. (Don't forget to start the projector motor, lest you burn the shutter!) What you should see on the screen is sort of a "bullseye" or "starburst" pattern of light. It should be almost perfectly symmetrical and centered on the screen. If not, you'll have dark areas in your picture. Have a knowledgeable person adjust the lamp alignment and beam spread/focus until it is centered. If these adjustments can't put the picture back in line then you have a problem that a technician needs to look at. Put the lens back in and take out the aperture plate. Project a white beam on the screen again. You should see an even white "wash" all over the screen. In fact, because the plate's out, you will see light going all over the wall! If you don't see this picture you might have a problem with your lens or with the lens alignment. If you don't know how to align the lens, have your tech do it. A small turn of the screw can make a big mess if you don't know what you're doing. Finally, put the plate back in. Project a white beam again. If your picture isn't a perfectly white rectangle of light, centered on the screen you have a plate alignment problem. It could also be a maladjustment of your turret. Either way, get your tech to come in and look at it. It's likely just a quick adjustment with a piece of test film and an Allen Wrench. Again, one false move on the tinkerer's part can mess things up royal! Of course, all this assumes that the projector is clean and there's no junk built up in the gate or aperture plate but, since you're here on Film-Tech, we don't have to worry about that, do we?  |  IP: Logged Paul Mayer Oh get out of it Melvin, before it pulls you under! Posts: 3836 From: Albuquerque, NM Registered: Feb 2000 posted 03-05-2003 04:58 PM                        You might want to check the height of the lamphouse in relation to the picture head. Also ensure that the douser or any fire or changeover shutters are fully retracted out of the optical path.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 03-05-2003 05:20 PM                        Definitely check your dowser. Also, if you're running a Century, make sure the fire shutter is opening all the way. I've had them get sticky in the past & do what you're seeing.  |  IP: Logged Joe Morris Film Handler Posts: 35 From: Papillion, NE, USA Registered: Jan 2003 posted 03-05-2003 05:30 PM                     I checked my douser, my shutter, my bulb, my lens, aperature, i've checked it all...and I got the shadow a little smaller by adjusting the spread of the bulb. BTW: I'm using a CFS SX-2000 console...big hunk a junk, and a monee projector identical to the Century JJ's i think...at least the parts are. but my shadow is still there...  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 03-05-2003 06:00 PM                    Have you ever had the reflector bowl replaced at anytime that you know of. I had this problem before and had to move the reflector bowl forward torwards the projector in order to get rid of the darkened area.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-05-2003 07:56 PM                        Does the light fill the screen without the aperture in? Does the light spill above the screen with the aperture in? Is this black area a well defined block with a straight edge?  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 03-05-2003 08:33 PM                     Joe, I have a question for you. Did you try inverting the aperture plate? It is sometimes possible to invert the plates in the Century type apertures and that can cause your problem if the plate is fitted to cut at the top. Just a thought! KEN  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-05-2003 08:36 PM                        I wondered about that too Ken, but he said he 'checked the aperture'. Not sure what he checked about it. Anyway, I'll toss in what I was going to add before... Has someone (accidentally) swapped aperture plates with another machine (not necessarily from the same screen). That, is if you have more than one projector or multiple screens.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-05-2003 08:51 PM                     Is the fire shutter or changeover plate not opening far enough? A straight line dark shadow along the screen bottom is not a lamphouse problem in my experience, lamphouse problems tend to be curved (like the reflector). Most likely an aperture or changeover, or the whole console has shifted.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-05-2003 09:15 PM                        I don't know why I missed this before... Does the problem only occur with a single lens / aspect ratio or does it happen with all of your lenses (flat and scope and others?)? I agree with Dave that the problem is likely forward of the lamphouse, that's why I asked above if the black area was a straight line.  |  IP: Logged Joe Morris Film Handler Posts: 35 From: Papillion, NE, USA Registered: Jan 2003 posted 03-05-2003 09:48 PM                     I have a Vertical lamphouse..i'm thinking that my mirror has been moved somehow...I will have to wait until I'm not showing a movie in there to check. I know it's not my aperature, it happens on both flat and scope prints, with or without the aperature. I haven't had the reflector dish replaced in 14 years...so it's not that. I will check my mirror and see what that does  |  IP: Logged Rick Long Jedi Master Film Handler Posts: 759 From: Toronto, Ontario, Canada Registered: Nov 1999 posted 03-05-2003 11:18 PM                     Willing to bet that the centrifical-driven fire shutter isn't opening all the way. These things do slip over time. Check the manual for proper adjustment. Only requires a screw-driver.  |  IP: Logged Gerard S. Cohen Jedi Master Film Handler Posts: 975 From: Forest Hills, NY, USA Registered: Sep 2001 posted 03-06-2003 10:41 AM                     Rick (above) nailed a problem I had long ago when working replacement at a single-screen in NYC. Lord knows how long the problem existed, but I traced it to a hanging fire shutter, and I was not able to correct it at the time. I reported it to the night manager, who called the Union office, and two men came down and tried to adjust it. The chain owner was alerted. He was a notorius alcoholic, and came down roaring drunk, spouting obscenities and cursing me out. I was trying to run a perfect show, but he didn't appreciate my efforts. I vowed never to work any of that man's theatres again, and never did.  |  IP: Logged

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