Film-Tech Forum ARCHIVE: Weird shadows on the edge of frame

This is topic Weird shadows on the edge of frame in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008035

Posted by Dan Chilton (Member # 2288) on 05-27-2006, 09:52 PM:

This just started recently: a slightly dark area along the top and bottom of the frame (more noticeable on the bottom). I've checked the aperture plates, and they seem fine. Cleaned out the projector, as usual. Cleaned the port glass, etc.. What could be causing this?

Here's what it looks like (created in PhotoShop)

Posted by Brad Miller (Member # 2) on 05-27-2006, 10:45 PM:

Remove the aperture plate and let us know if the fuzzy edges are still there.

Posted by Dan Chilton (Member # 2288) on 05-27-2006, 10:51 PM:

Brad: I wiggled the aperture plate, and the fuzzy/dark lines move with it.

Posted by Brad Miller (Member # 2) on 05-27-2006, 11:24 PM:

There ya go! Odds are someone moved aperture plates around between auditoriums. Regardless, give your tech a call and let him know you need an aperture plate trimmed or a new plate cut.

Posted by Martin Ubilluz (Member # 3769) on 05-28-2006, 01:32 AM:

you might need to focus your bulb also i would think if you have never moved your apature plate ever its prob you bulb focus

Posted by Monte L Fullmer (Member # 2797) on 05-28-2006, 01:40 AM:

adjustable masking settings slipped out of time? . seen many of that .. - Monte

Posted by Randy Stankey (Member # 64) on 05-28-2006, 09:07 AM:

Does the projector have a lens turret?

Could be the turret slipping out of position, moving the picture slightly off the screen and onto the masking.

The same thing can also happen if the projector doesn't have a turret but it's a lot more common with turrets.

Posted by Brad Miller (Member # 2) on 05-28-2006, 09:23 AM:

Bulb focus and masking stops are good suggestions. It's not your turret, as you said it was on both the top and the bottom.

I always forget about those stupid top/bottom masking auditorium designs. The masking theory will only affect those. What is your setup?

Posted by Dan Chilton (Member # 2288) on 05-28-2006, 12:06 PM:

No turret. One auditorium. No masking. We've used the same aperture plate since we opened, but the problem just started. Quite a conundrum indeed. How does one go about focusing a bulb without calling my tech and having him drive 4 hours to do it for me?

I'm on a Simplex XL with an old ORC lamphouse.

Posted by Jason Miller (Member # 2341) on 05-28-2006, 12:55 PM:

could the ap plate have annealed? might just need some touch-up work.

Posted by Martin Ubilluz (Member # 3769) on 05-28-2006, 02:48 PM:

deff bulb focus my lamp house has a bulb focus slot on the side of the lamp house that you need to stick a screw fdriver in you migh have to play with the verticle and horizontle too whitch on my lamp house is found on the same place play with the focus first though

Posted by John Wilson (Member # 269) on 05-28-2006, 10:53 PM:

quote: Dan Chilton
No turret. One auditorium. No masking.

No masking? I would think this is a normal look then.

Posted by Tommie Evans (Member # 2674) on 05-29-2006, 08:24 AM:

You also have another problem. . .

X-Men 3 is scope! [thumbsup]

Posted by Monte L Fullmer (Member # 2797) on 05-29-2006, 01:59 PM:

Tommie - you didn't read his descript: He did a photoshop of a scene from XM3 - prob scanned this scene from an ad page then touched up that scene to make it look like the imagry that is on his screen.

Posted by Tommie Evans (Member # 2674) on 05-29-2006, 05:00 PM:

quote: Monte L Fullmer
Tommie - you didn't read his descript: He did a photoshop of a scene from XM3 - prob scanned this scene from an ad page then touched up that scene to make it look like the imagry that is on his screen.

Hey, I was just joking. . .

Posted by Richard Hamilton (Member # 321) on 05-29-2006, 07:19 PM:

quote: Dan Chilton

No turret. One auditorium. No masking.

Also no theater.... I drove to Springfield and could not find the theater!!!, or the problem!!

Posted by Monte L Fullmer (Member # 2797) on 05-29-2006, 10:55 PM:

Sorry...didn't mean any harm then...

Posted by Glen Rich (Member # 1150) on 05-30-2006, 02:58 AM:

Can't say I actually know this kid, Chilton, but I have been reading his blog on setting up and running his and his wifes small cinema. Got the following from their web page,

Springfield's Premiere Independent Cinema • 408 W. Walnut, Springfield, MO 65806 • 417.429.0800

http://www.moxiecinema.com/

I'd check the lamp focus. Go to the manual for your lamp house, if you haven't got one you may well find it in the manuals supplied here, it will show you where the focus and lateral adjustment(horizontal/vertical), knobs/screws are. Take your time, it's one of those jobs you can do in a few minutes with practice. Be patient...

Posted by David Ingalsbe (Member # 2433) on 05-30-2006, 03:52 AM:

of coarse I think we missed something he said when he moved the ap plate the shadow moved with it so i would check for dirt fuzz or random crap stuck to it. or it may have been really heated up and re-aniled.(sp?)
or if i miss read the thread and missed something please excuse my own dumbness [Big Grin]

Posted by Richard Hamilton (Member # 321) on 05-30-2006, 06:42 AM:

quote:
Also no theater.... I drove to Springfield and could not find the theater!!!, or the problem!!

My bad, I was in Illinois.

Posted by Mark Gulbrandsen (Member # 72) on 05-30-2006, 07:35 AM:

quote: Jason Miller
could the ap plate have annealed?

FWIW: Yes, the brass could have annealed if the lamphouse you are using gets the brass hot enough to do so. That much heat typically comes from 3kw and higher lamp wattages though or from an improperly operating lamphouse without adaquate heat filtering(like missing hot mirrors). When the brass anneals it generally shrinks just very slightly but always all the way around... not just on one side. I've had many a high power lamp/projector that I filed the plates very tightly for only to have to go back and touch them up a month or more later.

Your problem looks to me like the projector has tilted up just slightly and you're seeing the bottom edge of the plate. Keep in mind that all buildings expand and contract with changes in the seasons and a slight re-aiming of the projector may be necessary. I see this all the time on systems with very tightly filed plates. Also lens mounts are not always that repeatably accurate... like old Simplex's with the stretching lens mounts that can no longer be tightened properly, or Simplex's with TU-2000 turretts and the dam nylon stopper screws that change dimension every time you close the turret. At new locations that have that dam carpeted booth syndrome the projectors slowly sink into the carpet and also require re-aiming.

Just some thoughts you can easily check out.....

Mark

Posted by Dave Macaulay (Member # 813) on 05-30-2006, 08:45 AM:

I've never seen an aperture plate get smaller unless someone peened the edges which would be quite obvious.
I've seen this phenomenon before, and it turned out to be a loosened rear lens element. The picture was focusable but smaller, like a zoom effect.
You might check that the rear element retaining ring is screwed in all the way.

Posted by Richard Hamilton (Member # 321) on 05-30-2006, 09:14 AM:

Possibly a Magnacom?

Posted by Dan Chilton (Member # 2288) on 05-30-2006, 11:59 AM:

I think Mark Gulbrandsen hit it on the head - the projector has been tilted up by just the smallest amount as the building continues to settle in the heat. We're in a very old building with a concrete slab foundation. Our auditorium has a 10" slope from the back to the front that was not planned... that's just the way our old building has settled. I'm going to file the plates back a bit and go from there.

As always, thanks for all your help guys! And yes, we're in Springfield, MISSOURI, not ILLINOIS... or MASSACHUSETTS.

Posted by Rick Raskin (Member # 1561) on 05-30-2006, 03:49 PM:

Why not just adjust the projector tilt instead?

Posted by Richard Hamilton (Member # 321) on 05-30-2006, 04:33 PM:

quote: Rick Raskin
Why not just adjust the projector tilt instead?

Because that could effect the weight distribution of an unstable building. Also if you tilt it, which way? The shadows appear on the top and bottom. Maybe the building is shrinking? Also , be prepared to buy new plates when the building gets cool again [Wink]

This is quite the conundrum!

Posted by Dan Chilton (Member # 2288) on 05-30-2006, 06:23 PM:

quote:
This is quite the conundrum!

I told you so.

Posted by Mark Gulbrandsen (Member # 72) on 05-30-2006, 08:21 PM:

Again, I see this all the time in older theaters. Generally some aperature plate size can be reached that works for hot and cold seasons providing that you have good quality masking to spill over onto. People rarely notice the spill over onto the black masking as their attention is normally focused on the moving image thay paid to see. So in your case touching up the plate would probably be appropriate thing to do but I would still run a target loop to be sure the projector is aligned to the screen properly before filing any plates out.

quote: Richard Hamilton
Because that could effect the weight distribution of an unstable building.

Thats an odd thought. Most of the very old theaters that I service are built alot better than almost any of the new construction being done today..... Its the new construction in which I would be seriously concerned about weight distribution. Light weight steel truss joists are just no substitute for a large set of old iron I-beams. Many of todays booth floors have condsiderable bounce to them after being loaded with all the booth gear.

Mark

Posted by Richard Hamilton (Member # 321) on 05-31-2006, 06:43 AM:

Dan,
I don't have anything scheduled for the rest of this week. If you are willing to cover my travel expenses, I could come over and look at the problem. I am 250 miles away, so it would cost you about 100 to 150 bucks(my car guzzles gas!)

Rick