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Author Topic: Dark sides in flat films. Brandon Lokesak Film Handler Posts: 34 From: Johnstown, PA USA Registered: Mar 2004 posted 05-15-2004 01:21 AM                     does anyone have any idea what could be causing our flat flims to have like a 4 inch dark side border to them. The left and right sides are extremely dark from top to bottom. Could this be due to the lamphouses being out of alignment. Its been like this ever since i worked there so it hasnt just happened. Its a cinnemacanica lamphouse with a lti 2000k bulb.  |  IP: Logged Mike Olpin Chop Chop! Posts: 1852 From: Dallas, TX Registered: Jan 2002 posted 05-15-2004 05:19 AM                     It sounds to me like your flat aperture plate is cut incorrectly. You can order a new one to be cut, but that can be expensive. Alternatively, you can set new stops for your side masking to cover the dark area. (But don't pull them in too much!) [ 05-15-2004, 08:13 PM: Message edited by: Mike Olpin ]  |  IP: Logged Steve Scott Phenomenal Film Handler Posts: 1300 From: Minneapolis, MN Registered: Sep 2000 posted 05-15-2004 08:44 AM                     What kind of projector is this, if it has a turret you may need to adjust the positioning of the lenses within the turret, or the whole assembly may be off some. If it's got a lens barrel, though, I'd agree with Mike, and check the plate.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 05-15-2004 08:55 AM                        If you have side masking, it could be that the masking stops are set wrong. The best way to check any of these issues is to run a loop of RP-40 (aka PA-35) with the aperture plate removed. This will show you where the edges of the image are supposed to be.  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 05-15-2004 01:03 PM                    I agree it sounds like an aperture problem. In flat, issues with misaligned lamps usually mean hot spots on the image, since flat is a smaller aperture than scope. So I doubt very much that your problem has anything to do with the bulb alignment.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 05-15-2004 01:47 PM                        If you're runing an XL series projector with a trap, the gate might be adjusted to place the film too far from the aperture. That can cause this effect by itself.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 05-15-2004 02:43 PM                     quote: Darryl Spicer In flat, issues with misaligned lamps usually mean hot spots on the image, since flat is a smaller aperture than scope Although this is probably not his problem, it could be that his screens have fixed masking at 2:1 and the lamp was tightly focused down on the scope format, creating dark sides on flat films. Regardless Brandon HAS to post more info about his system for anyone to give reasonable advice. I am going to start instigating a policy where if someone posts a problem and does not list all equipment involved that the thread is deleted if this sort of thing continues. All it does is waste people's time. In this instance all we know is that a 2K Cinemeccanica lamphouse is involved. Well...what model lamphouse? What model projector is blocking the light in front of it? Is there a turret involved? Are the dark sides straight vertical, or is there a curve to the sides? Etc, etc, etc  |  IP: Logged Brandon Lokesak Film Handler Posts: 34 From: Johnstown, PA USA Registered: Mar 2004 posted 05-15-2004 07:58 PM                     Its a century model SA. We have no side masking we have no lens turrent,The lines are perfectly straight down on both sides no curves. I dont know if its the apertures because its the same on both screens and the apertures are not in the wrong projectors. I dont know how much more information I can give to you about this problem. The apertures are rather worn maybe I will see about ordering 1 replacement for now to see if this fixes the problem. Sorry for the lack of information I thought I made it clear in the first post but I guess not. Sorry for wasting your time....  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 05-15-2004 08:25 PM                     quote: Brandon Lokesak We have no side masking we have no lens turrent That's great and all, but do you have any top or bottom masking??? Remove the aperture. Turn on the projector motor and xenon. Lift the douser (don't run it this way for very long - to be safe limit it to 20 seconds). Now tell me if you still see those dark sides or not.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 05-15-2004 08:53 PM                     I guess I will ask my queery in this dilema Is this shadow a clearly defined dark band that is parrallel to the edge of the picture or is the shadow having a larger darker area in the corners than in the centre of the sides If it is parrallel and clearly defined (the apperture in a SA is usually very sharp) then I would place bets on it being the plate or possibly the heat sheild behind it interacting with the lamphouse If it is moreso in the corners then I would look at lamphouse alignment. And on that issue is this a older vertical cinemecanica lamphouse or the modern horizontal version and what make and model of lens is involved.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 05-15-2004 09:01 PM                     TIP OF THE DAY - This sort of troubleshooting would be so much easier if people sent in picture tours of their theater. That way we could not only look at the make and model of equipment, but the way it is set up as well.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 05-15-2004 10:30 PM                     Another useful trick is to pull out the aperture partially and watch if the effect follows it. --jhawk  |  IP: Logged Jeremy Fuentes Mmmm, Dr. Pepper! Posts: 1168 From: Corpus Christi, TX United States Registered: Jan 2004 posted 05-15-2004 11:05 PM                     We have the same issue. Ballantyne projectors, with different types of lamphouses. Cinemeccanica, Xetron, Strong, and top, bottom, and side masking. Isco-Optic lenses, with turrets. It happens on all 5 of our screens, and they are all different size theaters. I actually fixed it on one of them once, by changing the lens, but our tech told me that I had the wrong lens in there, and switched it back to where it was, and took the other lens with him. I guess he thinks its supposed to be like that.  |  IP: Logged Brandon Lokesak Film Handler Posts: 34 From: Johnstown, PA USA Registered: Mar 2004 posted 05-16-2004 12:15 AM                     Yeah I know pictures would be nice...It would be much easier if I could find the cable to my digital camera ill just have to take some photos tommarow and scan them in. In responce to the top and bottom masking question there is no masking.  |  IP: Logged Carl Martin Phenomenal Film Handler Posts: 1424 From: Oakland, CA, USA Registered: Feb 2002 posted 05-16-2004 12:26 AM                        it sounds like the picture is as good as it's going to be unless you get movable masking. with a shorter lens you could fill the screen side-to-side, but you'd be cropping the top/bottom (some people might prefer that alternative). there's a good chance you're cropping the sides of your scope image as well. what are the dimensions of the visible screen? carl  |  IP: Logged

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