This is topic Scope going off bottom of screen in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Richard Greco (Member # 2032) on 12-08-2003, 07:33 AM:
 
Whenever I run a film in one of the DTS houses that is in scope, It always seems to run off the bottom of the screen, It is in frame, but it seems like the screen isn't tall enough. Great example is Haunted Mansion. It runs off the bottom. Any Ideas?

Also, as a side note, I can't understand why my theatre decided to book Brother Bear and Gothika in the same house. They even booked them in a house meant only for flat films, not scope. So, when I run scope in there it ends up on the wall. Do theatres typically do this? I'm not complaining about it, just curious is all.
 

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Posted by Darren Briggs (Member # 1071) on 12-08-2003, 07:41 AM:
 
Sound like your cinema was designed and installed badly.
The lens sizes don't match your screen and a badly cut apperture plate will cause the image to spill off the sides of the screen.
The wrong focal length lens will cause the image to be too big for your screen, a combination of the two is not acceptable really.
Get some new appertures plates cut if new lenses is not an option.

Darren
 

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Posted by Richard Greco (Member # 2032) on 12-08-2003, 07:52 AM:
 
I also did notice that one of my plates that I was using for Elf had 2.00 printed on it. The other plate doesn't have a number with it.
 

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Posted by Jason Black (Member # 684) on 12-08-2003, 08:43 AM:
 
Richard,

SOunds like you could have plates that are cut wrong, or that have been inadvertently swapped between houses.

Throw coudl be off on the lens as well. The masking could be set incorrectly... there are a number of things that *could* be wrong. First and foremost, if you have a house with no movable masking, your manager shoudl have known better than to put a Scope film in that house. There are no excuses that would cover her reasoning in doing so, as this is a fine example of "Film Done Wrong" .

My suggestion to you is that you ask who your PM (Preventative Maintainance) tech is and ask to be able to spend some time with him on his next routine visit. The PM tech normally will spend up to a couple days at a given location, depending on screen count, doing realignments, repairs, adjustments, etc...

Taking the time to walk around with them and helping them will bring you invaluable knowledge that will not only help you perform your daily tasks better, but will also help you have a better understanding of what is *really* going on in the booth.

I don't think you manager shoudl have any objection to this, as someone from the theatre is required to meet with the PM tech anyway. It may as well be someone who gives a damn about what's happening in the booth, right?

Good luck.
 

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Posted by John Walsh (Member # 168) on 12-08-2003, 08:47 AM:
 
That plate with "2.00" on it suggests that you are projecting a 2:1 ratio for all formats. Do you have adjustable masking?

You really need a length of the 35PA test film. Projecting it would help find the exact problem. It costs about $4-5 a foot, but you only need about 8ft.
 

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Posted by John Pytlak (Member # 331) on 12-08-2003, 08:53 AM:
 
If your dealer doesn't sell short lengths of SMPTE 35-PA (RP40) for making loops, you can buy 50 feet directly from the SMPTE for $180:

http://www.smpte.org/smpte_store/test_materials/

Loops are fine for checking image size, but do NOT use a loop for critical evaluation of resolution, focus uniformity, or steadiness.

Here's my article "Caring About Composition":

http://www.kodak.com/US/en/motion/newsletters/pytlak/spring2001.shtml
 

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Posted by Darryl Spicer (Member # 711) on 12-08-2003, 09:01 AM:
 
Wait a minute here. Lets not start talking about plates until we know a little more about what type of equipment he is using. Some questions need to be asked, Some may have been asked.

First off what type of equipment are you using. Are you using lens turrets that just need adjusting. Do you use an auto apeture changer or do you have to remove the plates when you change from each lens? Does your theater use top masking or side masking. Provide us with a little more information. How many ausitoriums do you have. Can the two films in question be moved to a different auditorium?

Was this 2.0 plate in the wrong projector?
 

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Posted by Scott Norwood (Member # 30) on 12-08-2003, 09:10 AM:
 
I'd ignore any numbers stamped into the plate. lots of places have Academy and 1.66 plates that are stamped "1.85" or some such. Almost all plates are "undercut" from the factory and filed out to whatever size is needed.

Agreed that we need more information. Do you have the correct plate and lens in the correct projector? Is the plate backwards/upside down? Has anything happened lately that might have caused the masking system to malfunction? Do you need to adjust the projector tilt when changing formats (easy with Simplex or Century pedestals, but almost never done with consoles)? What kind of projector? Turret or single-lens?
 

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Posted by Richard Greco (Member # 2032) on 12-08-2003, 10:06 AM:
 
My apologies for the lack of information.

I am using Century SA Projectors, Strong Lumex and Super Lumex lamphouses. I have 8 auditoriums. I checked the plates and the 2.00 plate is the standard plate at all projectors for Flat shows. The Scope plate doesn't have a number on it. I have to change the plate when I change the lens. I'm not sure what you mean with turett or single lens.

I use manual side masking in all auditoriums. The only automation is with the light system. I haven't been told to adjust the tilt for different shows. So I don't.

Is that enough information? If you need any more, I can find out.

I honestly don't know when my tech comes around next time.
 

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Posted by John Pytlak (Member # 331) on 12-08-2003, 10:19 AM:
 
You really need to look at the actual projected image area for each format, as measured with the SMPTE 35-PA (RP40) test film. Hopefully, you are showing close to the SMPTE 195 standard 0.825 x 0.446 inch ("flat" 1.85:1) and 0.825 x 0.690 inch ("scope" 2.39:1) image areas. If not, it should be corrected by proper choice of aperture image area, lens focal length, and screen masking.
 

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Posted by Manny Knowles (Member # 1171) on 12-08-2003, 10:33 AM:
 
I recently solved a problem where the aperture plates were a little suspect at first but turned out to be okay in the end. The trouble was with the alignment of the lenses and the aiming of the projector.

That location was using a lens turret and automated aperture plate.

By running a loop of RP-40 test film and switching between flat and scope lenses, I could plainly see that the images were not centered relative to one another. In this case, the scope image was too low.

The wonderful Align-O-Tron and a pinhole aperture plate helped get those lenses centred relative to the gate.

Suddenly -- with the lenses properly aligned to the gate area -- BOTH my flat and scope images were hanging below the screen. We had to re-aim the projector. We used the scope image (with no aperture plate) as our guide.

Once the scope image was properly presented on-screen, I went up to the screen and gently taped a piece of electrical tape to mark the centre of the diamond pattern.

Switched over to flat and noted the slight difference -- not nearly as drastic as before. Rather than fiddle about with the alignment of the flat lens -- which is handicapped due to reduced light output -- I decided to re-aim the projector to get the flat image to centre on the little piece of electrical tape.

Back to the scope lens -- tweak the alignment of the lens for matched centres on-screen.

Reinserted the suspect aperture plate and -- guess what? -- perfect fit!

...and then I removed the electrical tape from the screen (there was that one time that I forgot to remove it and I haven't forgotten again since then.)
 

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Posted by Antonio Marcheselli (Member # 373) on 12-08-2003, 07:32 PM:
 
Manny

There's somenthing I do not understand. You use align'o'tron to align the lens holder with the center of the aperture plate and you verify that, after the correction, the image was projected below the screen. Then you aligned the projectow using scope image without aperture plate. What about the frame knob? Does that projector has a "zero" point?

I dont know if I was clear...

Bye
A
 

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Posted by Randy Stankey (Member # 64) on 12-08-2003, 08:10 PM:
 
Try taking the aperture plate out of the projector while it's running and see what happens. (Wait till there aren't any customers in the theater! )

What will happen is that the picture will appear to go all over the wall, spilling onto the masking and maybe even onto the floor and ceiling. You should then be able to judge where the center of the image is. Once you have found that, try to tell if it's centered on the screen.

If the image without aperture is centered on the screen then it's almost a sure bet that somebody has mixed up the aperture plates you. (Sort them out and put NUMBERS on them to match the house numbers they belong in. )

If the image is NOT centered then you could have some kind of alignment problem. It could be that the lens is off kilter. It could be the projector has been aimed wrong.

If it's the lens, you'll probably have to call your tech. There are several funky things that could be wrong. If it's simply the projector being aimed wrong, that COULD be easy to fix!

If it's vertically off center, there may be an adjustment wheel on the projector base somewhere. Dial that baby in till it's back on the screen. 15 seconds and you're back in business! Virtually ALL projectors have a height adjustment. Some are easier than others. That's all.

If it's horizontally off center, it's time to "Play Croquet"!
Get a piece of 2 X 4, about 1 foot long. Lay it flat on the ground, right up against the projector base... A STRONG part of the base! Use a sledge hammer and "bump" the 2 X 4 as if you're playing a game of croquet. You should only have to swing the hammer in strokes of 6 inches to one foot distance. After 3 or 4 bumps check the picture. Keep bumping the projector until it's back in alignment with the screen.

One last thing... If you're getting anywhere near a projector with any kind of tool, let alone a sledge hammer, you should get your boss to come help you! That way you don't get accused of messing up the equipment.
 

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Posted by Steve Kraus (Member # 476) on 12-08-2003, 09:14 PM:
 
Sledge hammer? Why not a pry bar or very big screw driver?
 

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Posted by Randy Stankey (Member # 64) on 12-08-2003, 09:31 PM:
 
Well, then, let me rephrase.

Use some sort of tool to apply lateral force to the projector base and cause it to move in small increments until the picture is centered.

I've done it many ways, including simply kicking it with my foot. I guess it depends on how big and heavy the thing is or whether the base is sturdy enough.

Come to think of it, a crow bar is good.
 

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Posted by John Hawkinson (Member # 1135) on 12-08-2003, 09:34 PM:
 
You want a sledge hammer because you want to lightly tap the pedestal base in small steps. If you use a crowbar or a screwdriver, you're prying, which isn't desirable here. You just want to inch it over.

--jhawk
 

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Posted by Manny Knowles (Member # 1171) on 12-08-2003, 10:12 PM:
 
Antonio:

There is no "zero point" for framing my projectors -- actually, there is (kind-of) but it is not marked.

To find the zero point, I ran some RP-40 with the pinhole aperture plate in position and used the hole in the plate as the target for the diamond on the test film.

It is important to align the centre of the lens to the centre of the gate/aperture and not just the film.

-- Manny.
 

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Posted by Richard Greco (Member # 2032) on 12-08-2003, 11:39 PM:
 
The thing is, if I adjust the projector vertically, then the picture will be on the top curtain off screen. I am getting Stuck on You in that theatre Thursday, I'll see how that fares out. Could it be maybe the movie in the auditorium? I have Haunted Mansion in there right now.
 

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Posted by Darryl Spicer (Member # 711) on 12-08-2003, 11:50 PM:
 
What does your other screens look like. Do they have problems with the Scope image. It could be possable that the plate is the wrong one for that house.
 

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Posted by Richard Greco (Member # 2032) on 12-08-2003, 11:52 PM:
 
Darryl, all of the other screens (aside from the 3rd, which only does flat) play scope fairly well. I did notice that this screen seemed to be curved more on the left than the right.
 

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Posted by Gordon McLeod (Member # 33) on 12-09-2003, 12:11 AM:
 
Pinhole plates often are punched uncentred
I use the 35PA and adjust the framer to produce an equal location setting at the extreme edges of the projected trap
 

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Posted by Antonio Marcheselli (Member # 373) on 12-09-2003, 03:22 AM:
 
Manny

I agree, but then you said that you align the (aligned) projector using the scope image without aperture plate... How can be sure that the frame setting is correct? You said that you set the frame using the pinhole aperture plate, ok (if the hole is in the center).

Gordon,
If Pinhole aperture plate has not always the pin in the center of the plate, how can a aperture plate be made? Since I adjust the plate basing on RP40, how can be sure that RP40 is in perfect frame?

I still don't know if I'm clear! ask if necessary!!

Bye
A
 

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Posted by Manny Knowles (Member # 1171) on 12-09-2003, 08:46 AM:
 
Gordon:

Ordinarily, I would defer to your deeper level of experience with a variety of equipment. I am sure that you have seen many a funky-looking pinhole plate so I'm not going to disagree on that point.

In my case, however, these pinhole plates look just fine to me. Sure, they *could* be off-centre by a millimeter or so -- I never measured -- but I'm not really interested in splitting hairs over that.

I'm using the same pinhole plate for each projector and I think that gives me a better shot at consistency than just "eyeballing it."

-- Manny.
 

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Posted by Randy Stankey (Member # 64) on 12-09-2003, 10:14 AM:
 

quote:

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Antonio Marcheselli: How can be sure that the frame setting is correct?

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I don't know how others think about this but, for the problem at hand, I don't think exact centering of the frame is called for. I think that all Richard needs to do is get the picture back on the screen then log the problem so that the tech. can look at it later. (Political factors aside.)

Therefore, in this case, it would be sufficient to pull the aperture plate to see whether the image is generally where it's supposed to be. From that point, minor, temporary adjustments can be made to keep the show on the screen. (Literally! )

Dialing the projector up or down is something that can easily be "undone". If the projector is bumped laterally, there should be no problem bumping it back if it must. I don't think most techs would get bent out of shape for things like that. They probably WOULD if other adjustments were made without his/her permission!

What's got me concerned is that Richard gives me the impression that somebody in management has "cheaped out" and has bought only one lens for some of the projectors.

Do you have two lenses and two aperture plates for each projector?

Don't worry about whether the masking moves on the screen. (Either manual or motorized.) Some companies "cheap out" and make a "One size fits all" screen. It's not the best thing to do but, if this is what has been done, you'll have to live with it.

What I think is happening is that somebody has come along and switched lenses and aperture plates between projectors. I think there may have been some lenses damaged (lost?), which is why some houses only seem to play one format.

Before going around and moving/adjusting any projectors, what *I* would do is make an inventory of lenses & aperture plates for each projector. If there is any clue that plates and lenses have been swapped around I would ensure that they are all back in the places they are supposed to be before going any further.
 

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Posted by Antonio Marcheselli (Member # 373) on 12-09-2003, 12:11 PM:
 
Randy,

Yes, I was Off topic, my questions were about centering the projector!

Bye
A
 

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Posted by Gordon McLeod (Member # 33) on 12-09-2003, 12:38 PM:
 
Antonio said "Gordon,
If Pinhole aperture plate has not always the pin in the center of the plate, how can a aperture plate be made? Since I adjust the plate basing on RP40, how can be sure that RP40 is in perfect frame?

I still don't know if I'm clear! ask if necessary"

The 35PA is shot in a pin registered camera and it is the reference to the recomended practice 40

All one has to do is open the pin hole up with a dremel tool and file to the correct dimensions for the format desired

I have seen punched out plates all over the map for location
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 12-09-2003, 12:50 PM:
 

quote:

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how can be sure that RP40 is in perfect frame?

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quote:

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You want a sledge hammer because you want to lightly tap the pedestal base in small steps. If you use a crowbar or a screwdriver, you're prying, which isn't desirable here. You just want to inch it over.

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I make tiny corrections with my bases all the time (re separate discussion about lens mount misalignment) using a crow / pry bar. I have no problem making millimeter changes. This is with a conventional base (later Ballantyne) with leveling screws in use not a console with with long leveling screw legs.
 

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Posted by John Pytlak (Member # 331) on 12-09-2003, 01:02 PM:
 
The center of the aperture opening (or pinhole) should be on the exact optical centerline of the lamphouse and lens. It's that simple.

With cast iron bases, gently prying it into place is less risky than hitting the brittle metal with a sledge hammer. Use a piece of wood to spread the stress of the prybar and not damage the base.
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 12-09-2003, 01:11 PM:
 
I too have used a crowbar for years to make small adjustments of the base on a screen with a 300' throw. Never had a problem. In fact using a crowbar allows for more precise movement than any sort of mallet.
 

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Posted by Antonio Marcheselli (Member # 373) on 12-09-2003, 02:01 PM:
 
Uhm, no, it wasn't what I mean.

If I center the lamphouse and the len's holder with the center of the lamphouse, I'm sure that my projector is internally aligned, right? My question is: When I thread 35PA I can move its position using the frame knob. If I project the image without aperture plate how can I be sure that the 35PA is perfectly in frame, since I have to use it to center the entire projector on the screen? While I was writing I found the answer by myself: put the align'o'tron in the previously centered len's holder and frame the PA35 until the center of it is on the laser. Right?

And what about if I don't have align'o'tron? Frame PA35 by eye don't seems to me the best solution.
 

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Posted by John Pytlak (Member # 331) on 12-09-2003, 02:09 PM:
 
Do you have a lens jig for doing "string" alignment? On many aperture plates, the horizontal center line of the desired image area is also the horizontal centerline of the plate itself.
 

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Posted by Daryl C. W. O'Shea (Member # 1303) on 12-09-2003, 02:29 PM:
 
You don't frame it by eye looking at the trap, you look at the 35PA image projected on the screen and wall. The outline of the trap acts as an aperture. You know the trap outline in centred, so you just have to centre the framing based on the trap outline as it is projected.

If somebody can take a picture of 35PA being projected without an aperture I think Antonio would understand what we're talking about.
 

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Posted by Antonio Marcheselli (Member # 373) on 12-09-2003, 04:54 PM:
 
Trap is the gate?

I understand, but what about when your window is not big enough to project the trap shadow on the back wall? and what about when the 35PA is projected on the ceiling? How can I center the 35PA if half of them is projected on the ceiling?
Again, I can reply by myself: put a piece of something (paper?) in front of the projector to project the whole image. I didn't know that the gate outline is reliable to make this adjustments.

Did I miss something?

Bye
A
 

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Posted by Gordon McLeod (Member # 33) on 12-09-2003, 05:50 PM:
 
If you have aligned the guides and lateral guide roller to the intermittent sprocket (another issue) then the window of the trap is accurate
 

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Posted by Steve Kraus (Member # 476) on 12-09-2003, 06:19 PM:
 
But that's horizontal and I would think the 35PA/RP40 image would be the most accurate there. It's the vertical position I wonder about since the test film will be naturally affected by framing adjustment. You have to start somewhere so I guess a position halfway between gate or trap components is as good as any.
 

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Posted by Gordon McLeod (Member # 33) on 12-09-2003, 06:29 PM:
 
Using the trap as a apperture and adjust the framer to centre the 35PA image in that window (I often put a card on the porthole and focus it on that) and that wil be the centre to align the lens mount to and then file to
 

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Posted by Richard Greco (Member # 2032) on 12-12-2003, 09:33 PM:
 
Hey guys,
Foud out the problem. It seems that the aperature plates were changed before I got there. I looked at the plate for the projector in question and it said it belonged to projector 1. I go to projector 1 and sure enough, there is an aperature plate that is filled in on the bottom. It works now, but it seems to be too narrow. Any ideas on that?
 

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Posted by John Pytlak (Member # 331) on 12-15-2003, 03:41 PM:
 
The bottom line is show as much of the image area specified by standard SMPTE 195 as possible, measured using the SMPTE 35-PA (RP40) test film:

http://www.kodak.com/US/en/motion/newsletters/pytlak/spring2001.shtml

You need the correct focal length lens and aperture plate for each format, to just overshoot the black screen masking that defines the actual image area by a little bit. If people mixed up your aperture plates, lenses, and masking stops, you should ask that a service engineer look at what you have and make the necessary recommendations.
 

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Posted by Randy Stankey (Member # 64) on 12-15-2003, 04:40 PM:
 
Richard,

Bonus for you! You solved a projection problem and you didn't have to use tools and adjust machines to do it!

What do you mean by "...seems to narrow..."?

If the rectangle of light coming out of the projector matches up with the edges of the screen/masking it's likely you're OK. (Or at least as OK as you're going to be, anyway.)

What some theater builders do to save money is to make a "One-size-fits-all" screen. The sides or top of the screen masking are stationary and don't change when you go from FLAT to SCOPE. (Or vice versa.) The problem is that you end up cutting off some of the sides of the picture when you show a SCOPE movie and you end up cutting off some of the top/bottom of the picture when you are in FLAT. It's a sucky way to do things but you're going to have to live with it and make the best of it. There's not a lot you can do to change things at this point.

The easiest way to tell is that when you go from FLAT to SCOPE the picture seems to stay the exact same size. If you're watching a SCOPE movie, when you see credits on the screen they'll probably go right to the edge of the picture, even though you know they're not supposed to. If you're watching a FLAT movie and you are in a closeup shot, it'll look like some of the tops of people's heads are being cut off and parts of their chins are chopped off.

Now, if the picture doesn't fit the screen exactly (or nearly exact) they there is another problem. If the aperture plates have been swapped around on the projectors I can't imagine why the same person or persons couldn't have moved lenses around too! If this is the case it could be hard to figure out which lens goes where unless you're up for a fair bit of "trial and error".
 

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Posted by Richard Greco (Member # 2032) on 12-15-2003, 05:33 PM:
 
What I mean Randy is when the picture seems to narrow, I noticed that the plate was filed wrong on the soundtrack side. It was filed at an angle.
 

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Posted by John Pytlak (Member # 331) on 12-16-2003, 09:11 AM:
 

quote:

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What I mean Randy is when the picture seems to narrow, I noticed that the plate was filed wrong on the soundtrack side. It was filed at an angle.

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