Film-Tech Forum ARCHIVE: Simplex X-L Aperture Plates(replacement/filing question)

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Posted by Ethan Dutcher (Member # 8319) on 06-19-2014, 12:42 PM:

Hello all,

I've recently started at a location with a Simplex X-L and my current aperture plates are casting shadows on screen. The scope is a slight shadow on the top of the image in the upper right corner, starting in the middle and getting larger as is approaches the right side(in addition I am slightly bleeding past the lower right of the screen, this doesn't seem to be a lens issue since I've made numerous adjustments and the image looks great without the plate). My flat plate casts a shadow down the right side of the image. I'm wondering if anyone knows of a place to get replacement plates(I realize they won't be new, just if anyone somewhere has older pre-cut ones to sell)? Or possibly if someone could give me a little direction on filing the plates myself, the shadows are so slight that most of the people here had not noticed them before I pointed them out. The top shadow on the scope plate doesn't even completely block the image, just makes it slightly darker than it is supposed to be.

Posted by Victor Liorentas (Member # 5272) on 06-19-2014, 01:00 PM:

Do you have any RP40 test film?
It's good to have because it tells you what should be visible on screen without guessing.
If these plates are under filed then they could be filed a touch more to put shadow on masking. That is if they are under filed. If they are already filed to the limit,you will get unwanted crap on screen and masking.
Your scope lens could also be crooked? Need to check that as well as flat and scope being centered.

You should still be able to get test film,new aperture plates from a supplier. The best file for the job would be a flat file from Lavezzi Precision Inc.

Posted by Ethan Dutcher (Member # 8319) on 06-19-2014, 01:33 PM:

No test film unfortunately, I've been using green band for that purpose(old trailers). I suppose I could try to test the alignment of the lenses. They are obviously already seated in the adapters for the X-L projector, I was hoping to avoid reseating in those assemblies. With the flat lens/plate I can get the image looking good if I loosen the lens locking and clamping screws a bit and hold the lens in place, and also use a 'shim'(just a small piece of metal) behind the plate to push it forward(it is a little loose in the gate assembly). But the moment I let go of the lens, or tighten the locking/clamping screws, the image drifts to the left and I get the shadow on the right. The scope lens assembly has too tight a fit in the front of the projector to move the lens in anyway once it is fully inserted(it is actually a real pain to get in). I would honestly rather a slight bleed onto the masking than a shadow on screen, I think the bleeding is far less noticeable.

Posted by Dave Macaulay (Member # 813) on 06-19-2014, 01:51 PM:

The scope image sounds like your lens is rotated a bit from where it should be. That is easy to fix, loosen the mount and the stop ring and turn the lens until the image fits the screen. The stop ring should be positioned so the focus rack is centred, scope and flat lenses should match focus so no adjustment is needed when swapping lenses. On a new setup you need RP40 for the good vertical and horizontal lines to set the anamorphic position plus the focus charts to set the anamorphic focus, but assuming the lens and plates were set up correctly once and haven't been buggered with then a little touchup on the anamorphic position should be all it needs.
If you do need to file the plates, be very cautious - you can file them larger but it's quite a trick to file them smaller. The lens reverses everything: to move out the top left image corner you file the bottom right plate corner. This is where beginners usually mess it up. The filed edge should bevel away from the film side, a flat edge makes a much softer shadow edge than a beveled one.

Posted by Victor Liorentas (Member # 5272) on 06-19-2014, 02:07 PM:

What about shifting the projector itself a bit sideways and also raising or lowering?
That is sometimes necessary.
If flat needs to move,you can loosen lens locking ring and rotate the lens barrel while running your test film.Lock it down when its closest to the right position and then tighten ring back in place. Dave gives good advise above! [Smile]

Posted by Scott Norwood (Member # 30) on 06-19-2014, 02:17 PM:

Somewhere in the archives (which I cannot find now...argh!), Brad posted a good set of instructions of how to do this.

It basically came down to making sure that the lamphouse is aligned with the projector and that the projector is aligned relative to the screen before cutting anything. The worst thing to do is to waste time cutting new plates before realizing that your setup has unrelated issues that need to be resolved.

Assuming that you have movable masking, you need the RP40 loop in order to find out if the shadow represents an issue with your masking stops or with your aperture plates. It is also possible that there is a lamphouse alignment issue that is causing the shadow. If you have a changeover booth, make sure that the lenses and/or plates have not been inadvertantly swapped from one machine to the other.

If you are really on a budget or pressed for time and have no chance to get RP40 (been there, done that), get a good copy of an SMTPE leader (the clock-sweep one) and make a loop out of it. It has vertical and horizontal lines that you can use to center the image on the screen left-right and top-bottom. The outer circle represents the top and bottom limits of the Academy (1.37:1) frame, while the inner circle around the number represents the top and bottom limits of the 1.85 frame (there is nothing for 1.66, unfortunately). Using this, you can at least make sure that your image is centered on screen and that your scope lens is not twisted.

And, yes, you should get the Lavezzi aperture files (you need the flat one for edges and the half-round one for corners).

Posted by Ethan Dutcher (Member # 8319) on 06-19-2014, 02:21 PM:

Thanks guys. I know the projector was moved at least once to make room for a DLP, I'll look into getting some real test film. This is my first non-turret system so lens alignment was rarely an issue at my previous theatres. I'll spend some more time with it and see what I can do.

Posted by Rick Raskin (Member # 1561) on 06-19-2014, 03:36 PM:

An old trick is to project some film without an aperture plate installed. The image on screen will tell you if your plates are filed correctly or if you masking needs to be adjusted. You can also rack up the frame line to see if your machine is leveled. It also works for scope to get the horizontal alignment set. I do recommend an RP40 loop if you can get one.

Posted by Jack Theakston (Member # 4484) on 06-20-2014, 02:50 PM:

Do NOT cut all the way out to the edges. There's a certain amount of protection area in the Academy spec that may or may not actually have printed image depending on the camera gate and printer gate.

The only correct way to do this is with a test loop.

Posted by Gary A. Hoselton (Member # 3447) on 06-20-2014, 11:21 PM:

For RP-40 test loop, last fall American Cinema Equipment in Portland OR had some 35mm Schneider version of RP-40, which puts a nice test pattern on screen--every aspect ratio known to man I think. Contact Tom McGowan as he knows where the stuff is, which was in the basement. You'll need 10' for a Simplex XL, and, after splicing it into loop, very lightly wipe it with FilmGuard or similar light lubricant before running or the rails in the trap may eventually wear into the filmbase.

Posted by Monte L Fullmer (Member # 2797) on 06-20-2014, 11:37 PM:

Even digital projectors gets bumped out of center also and that's fun to get back in the middle, esp if your port windows are small.

Ya, do the PA-35 (RP-40) thing through a FLAT lens without aperture plate to get things back in center.

Then, if SCOPE without aperture plate is all but wiggered out of center, the prime section of the lens in the adapter clamp for the XL could be off-center a bit.

Always do FLAT first.

Monte

Posted by Dave Macaulay (Member # 813) on 06-21-2014, 10:19 AM:

I think I have a roll of SMPTE RP40 in a bin somewhere, I can send you enough for a loop. I don't have a need for it except on very rare occasions now.

Posted by Ethan Dutcher (Member # 8319) on 06-23-2014, 12:15 PM:

Once again, thanks for all the input everyone. The scope lens was just slightly twisted, I got that adjusted and did some very minor filing to get it looking great. I'll be looking at the flat lens again once I get in some test film(I was able to get some ordered). I appreciate everyone's advice, it really helped.