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Author Topic: What causes border shadowing on the screen? Richard P. May Expert Film Handler Posts: 243 From: Los Angeles, CA Registered: Jan 2006 posted 02-06-2011 11:45 AM                     The lens focal length could be too long for the size screen + throw, causing a smaller image than it should be. Filing aperture plates out too far would be more likely to start showing edges of the film that aren't intended to be on the screen, such as DTS timecode.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-06-2011 12:57 PM                     Then the proper lens should be ordered or the masking adjusted. A visible shadow around the screen edge is simply wrong...and here is a great example of a terrible aperture. If you look at the right side, the bottom half, the tech almost got it right. However everywhere else  |  IP: Logged Jeremy Weigel Phenomenal Film Handler Posts: 1062 From: Edmond, OK, USA Registered: Mar 2007 posted 02-06-2011 02:33 PM                     I like to place a few pieces of white copy paper on the masking and mark the 6" bleed over limit mark so its easier to tell when I'm getting close to the limit. The thickness of the plate can also make it difficult to eliminate the shadow completely, before over cutting past the 6" allowance. I like to bevel the back of the opening on Simplex plates to make for a thinner plate at the opening for this reason. My favorite plates to cut are the Christie's due to the thinness of the aperture. They are much easier to get no shadow with very little bleed on the masking.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-06-2011 03:09 PM                     Christie definitely beats all other projectors hands down in this department. Probably the worst out there is the Kinoton. Cutting the plate diagonally is a must, but that edge must be carefully smoothed out and tested to ensure there is no aperture scratching happening to the film.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 02-06-2011 03:13 PM                        Ug. I know what you mean about the Simplex plates. I am not a fan.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 02-06-2011 06:06 PM                        Nothing is wrong here with the projector, lens or plate, assuming his plate is cut properly to PA35 -- if so, then it's just a matter of adjusting the masking correctly to cover the fuzz, not trying to get a lens to overshoot the masking. Besides, that little bit of fuzz won't be fixed with the next step down FL lens as that would enlarge the picture much more than necessary and the masking would have to be adjusted anyway. Not to mention that it would also screw up his scope image.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 02-06-2011 10:04 PM                     quote: Jeremy Weigel I like to bevel the back of the opening on Simplex plates Would it not make more sense to bevel the opening outward (towards the lens) so that the edge closest to the film is sharp and defined?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-06-2011 10:34 PM                     Masking systems should be adjusted to be as close as possible to ideal on PA-35 test film. Then the aperture plates should be filed to the masking, not the test film. This way curved screens and other factors such as off-center projectors and downward tilt are taken into account when filing to produce a pleasing and sharply defined image. If this wasn't the case and every theater was absolutely perfect with one projector, dead centered and with 0 degree tilt, aperture plates wouldn't be supplied as "undersized" with the intention of filing.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 02-07-2011 12:12 AM                        quote: Eric Robinson Would it not make more sense to bevel the opening outward (towards the lens) so that the edge closest to the film is sharp and defined? That's what he's saying. The side towards the lamp should be sightly bigger than the side towards the film.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 02-07-2011 12:27 AM                     quote: Joe Redifer The side towards the lamp should be sightly bigger than the side towards the film. What you are saying would imply that the aperture plate is between the lamp and the film. I'm talking about aperture plates which are between the film and the lens, not between the lamp and the film.  |  IP: Logged Chase Pickett Expert Film Handler Posts: 142 From: Irving, Texas, USA Registered: Nov 2010 posted 02-07-2011 12:56 AM                     Honestly I think that theater cracked a flat lens, and replaced it with another from an different auditorium with a different throw and/or screen size. Although it could very well be the aperture plate too. I had to do the same thing after a flat lens decided it didn't like it's place in the lens turret. We luckily have schneider flat lenses that offer "a unique variable iris feature" that allows us to widen/shrink the image. Before adjusting anything, after just swapping lenses, the image looked very similar to the one you posted.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 02-07-2011 01:13 AM                     I am not a fan of Magnacom or variable iris lenses. The booth monkeys always seem to change the lens settings (even when locked down) and then the picture looks like ass.  |  IP: Logged Chase Pickett Expert Film Handler Posts: 142 From: Irving, Texas, USA Registered: Nov 2010 posted 02-07-2011 01:31 AM                     quote: Eric Robinson I am not a fan of Magnacom or variable iris lenses. The booth monkeys always seem to change the lens settings (even when locked down) and then the picture looks like ass. haha I can't agree with you more. The "lock" on the schneider lenses we have are way too easy to turn. I can honestly stick a pen cap in place of a hex key to rotate it. But, we have strong projector heads, and to be honest, I think their lens turrets are garbage because of shadows being caused by the lenses coming out of alignment. Even when closed/opened very very very gently. Plus I swear you unlock the lens, adjust it, then when you go to tighten the locking bolt you will knock the lens out of adjustment again. Needless to say, with those lenses and projector heads, I'm constantly battling shadows.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 02-07-2011 02:11 AM                        quote: Eric Robinson I'm talking about aperture plates which are between the film and the lens, not between the lamp and the film. What bizarre, non-common Simplexes are you threading?  |  IP: Logged Scott Jentsch Phenomenal Film Handler Posts: 1061 From: New Berlin, WI, USA Registered: Apr 2003 posted 02-07-2011 03:27 PM                        The presentation was film, not digital. Marcus is a chain that desperately needs to replace all of their film equipment with digital, because they seem to have a problem getting jump and weave under control. Those two issues were pretty much missing in screen #11, so I guess I have to choose the lesser of their evils... I looked back at the booth window, and there was no tape on the glass (that was my first thought). The effect was pretty close to what I showed in the example. Nearly uniform all the way around the image. Thinking back on it, the amount of shadow was probably greater, but the example is pretty close. The auditoriums at this location are all over the board. If you look at my Reader Comments for the Marcus Ridge, screen #5 had an alignment issue with Kings Speech on 1/8 and Harry Potter was about right masking-wise on 12/22. I haven't written about Tangled and 127 Hours yet, as I wanted to get some confirmation of what I was seeing before mentioning it. I usually go to Showtime Cinema in Franklin, which does a better job, but convenience of showtimes and the need to burn some gift card balances has sent me to Ridge more often in the past two months than in the past two years.  |  IP: Logged

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