Film-Tech Forum ARCHIVE: Print causing horizontal unsteadiness

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Posted by Joshua Burnham (Member # 1640) on 09-01-2004, 05:44 PM:

I run Christie Projectors M35 heads, SLC consoles. On our print of "Exorcist: the beginning" last evening it started weaving back and forth horizontally during the beginning of the fourth reel. I came in to check out the situation and sure enough there was a problem. First I had assumed my lateral guide roller just took a dump on me so I replaced the trap assembly. To my disbelief I still encountered the same problem. Fortunatly this happened during the last show with no one it (Big surprize). So after the showing had got out I ran a different print in the same house. The second film I ran Yu-gi-oh played all the way through without a hint of unsteadiness. So this morning I came in backed off the exorcist to check for anything done incorrectly, after having not found any problems I went ahead and ran the exorcist in a different house and IT STILL DOES IT! So now film-techers I am baffled. Has anyone been victim to this pain in the ass?

Posted by Steve Kraus (Member # 476) on 09-01-2004, 06:13 PM:

Are you saying it ran steadily originally, that the unsteadiness was not in the printing?

A sure way to tell is to pull the aperture plate and try to see the projected image of the sprocket holes. Their visibility will vary with the projector but if you can see them or part of them and they are steady then the projector is doing what it's supposed to do. Printer induced unsteadiness is not uncommon--in that case you would see steady perforations while the image bounces around.

Posted by Joshua Burnham (Member # 1640) on 09-01-2004, 06:29 PM:

Steve,

Thank you for the excellent response I have work in the booth for about 4 years now and have never encountered a problem like this. I unfortunatly could not tell you if it has been unsteady since its first run because I did not build or screen the feature. On my watch I do regular checks but it occurs during the middle of the movie and until now I wouldnt have known what I was looking at. Ill will try your idea and see what the results are. what could it be if not a print issue?

Posted by Steve Kraus (Member # 476) on 09-01-2004, 06:49 PM:

Well if the problem moved with the print (and another print showed the projector to be fine) then it has to be a print issue, no? But while it's possible that it's some physical issue with the print I'd bet it's simply crappy lab work. If it was a film anyone was watching you could ask for a replacement reel.

Posted by John Pytlak (Member # 331) on 09-02-2004, 05:31 AM:

As Steve notes, pull the aperture plate and project a bit of the print film perfs on the screen. If the perfs are rock steady, your projector is doing its job, and the image unsteadiness is upstream in production or printing. If the perfs are moving, your projector is not properly guiding the film, or the print has been damaged in some way.