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Author Topic: What causes border shadowing on the screen? Scott Jentsch Phenomenal Film Handler Posts: 1061 From: New Berlin, WI, USA Registered: Apr 2003 posted 02-04-2011 06:04 PM                        I attended a showing of Tangled with my daughter on Saturday at the Marcus Ridge Cinema in New Berlin, WI, and noticed a problem with the projected image, where there was a shadow that appeared around the entire border of the screen. I mocked up a photo to show the effect I noticed: This is the same image without it, for comparison purposes: As misfortune would have it, I ended up in the same auditorium last night to see 127 Hours. Same problem appeared on that movie as well. Given the uniformity of the issue, I'm figuring it might have something to do with the aperture plate? Is this a normal shadow that would not be visible if the image were increased in size so that the shadow would fall onto the masking instead? Something else I noticed last night was that it appeared that a band of the screen was different than the rest. Just left of center, about three feet of screen reflected the light differently, which was quite noticeable in the slow shots of the desert in the movie. Looking at the screen up close after the movie didn't show anything obvious. Any ideas on what caused this?  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 02-04-2011 06:28 PM                     Tandled 2D or 3D? Any idea if it was digital or 35mm? It it was film then in theory you could have been seeing aperture plate shadow on all 4 sides. This certainly seems like the most probable. (If it was digital then you wouldn't have had shadow. Even if the picture was undersized the edges would be crisp with a black border, not a shadow)  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 02-04-2011 07:23 PM                     I might be wrong but, as far as I know, whether the image is projected from a digital projector or a real projector, the borders of the picture can still look feathered (hazy/fuzzy) if the screen masking doesn't come in far enough.  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 02-04-2011 07:39 PM                     How would you get any shadow from digital? The shadow with traditional film projection comes from the distance in the gate between the aperture plate and the film.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 02-04-2011 07:50 PM                        Film apertures are permitted to be 6" into the masking. Good luck doing this in practice with the dirty masking. If you try to keep the picture off of the masking you will get what you describe. Digital, of course, is perfect! Louis  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 02-04-2011 08:37 PM                        quote: Randy Stankey I might be wrong but, as far as I know, whether the image is projected from a digital projector or a real projector, the borders of the picture can still look feathered (hazy/fuzzy) if the screen masking doesn't come in far enough. I can confirm that you are indeed incorrect on this. The edges of the digi-picture are sharp. The picture described by the O.P. is definitely caused by the aperture plate being just a hair too small, or the masking not coming in far enough.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-04-2011 08:57 PM                     Some people INTENTIONALLY file their apertures like this, using the incorrect logic that the picture should not be on the masking. The entire PURPOSE of masking is to give a crisp, sharp edge and the "fuzz" or "shadow" from the edge of the aperture is supposed to be covered up by the masking. What you saw was an improperly setup projector.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 02-04-2011 09:29 PM                     My digital projector shows feathering/shadow around the edge of the picture but it's a Christie HD8K, not a digital cinema projector. The effect is less than that of our 35mm projector but it is noticeable. Cinema projectors are probably different. Still, I believe that the effect seen is due to improper aperture or masking. If, as you all say, this does not happen with digital cinema projectors then I would conclude that the image in question was projected via 35mm.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-04-2011 09:45 PM                     Oh you vidiots....I can "set up" all of your DCinema projectors to have that EXACT type of shadow show up. If you have a digital projector and see such a thing occur...call your tech immediately though...it is an indication that your integrating rod is miss-aligned. If you see shadow on only a side or two (not all four) then it is more likely a folding mirror. The problem with a misaligned mirror/integrator is that the DMDs are designed to reflect light...the parts outside of the image area, are not and a misalignment will put excess heat on those parts. However, an improperly masked image with film projection is the most likely explanation in this case. However, to completely discount the possibility of DCinema because "they don't do that" would be wrong. -Steve  |  IP: Logged Victor Liorentas Jedi Master Film Handler Posts: 800 From: london ontario canada Registered: May 2009 posted 02-04-2011 09:49 PM                     Was the dark fuzz around the image as even as your example photo? If so it's astonishing how carefully wrong it is! Usually you see one side,top or bottom showing aperture plate due to sloppy projectionists who don't get it or even see it! Perhaps it was perfect and a Magna-com lens got zoomed down a tad.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 02-04-2011 10:03 PM                        An incorrectly aligned lamphouse can also cause the issue you describe.  |  IP: Logged Paul Linfesty Phenomenal Film Handler Posts: 1383 From: Bakersfield, CA, USA Registered: Nov 1999 posted 02-04-2011 11:27 PM                     The original Valley Plaza Cinema in Bakersfield also showed this effect, but as there was the proper slight image on the masking, I always assumed it was being caused by the theatre's flat masking with the screen's slight curvature behind it. Both the top masking (used only for 1.66 and, presumably, 70mm) and side masking as well. They just didn't fallow the curve of the screen.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 02-04-2011 11:45 PM                     And of course, some idiot could have carefully put masking tape on the projection window to keep the image off the masking. I see this done all the time - apparently they think the big huge fuzzy fucking shadow is somehow palatable.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 02-05-2011 01:16 AM                        quote: Sean McKinnon An incorrectly aligned lamphouse can also cause the issue you describe. I was going to say the same thing.  |  IP: Logged Jeremy Weigel Phenomenal Film Handler Posts: 1062 From: Edmond, OK, USA Registered: Mar 2007 posted 02-05-2011 10:29 AM                     quote: Eric Robinson And of course, some idiot could have carefully put masking tape on the projection window to keep the image off the masking. I see this done all the time - apparently they think the big huge fuzzy fucking shadow is somehow palatable. I've had to this before when someone got "file happy" and way over cut the aperture plate. It was better than having the picture bleed way off on to the white side curtains until a new plate came in.  |  IP: Logged

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