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Author Topic: shaky picture - ? - however... Jim Henk Master Film Handler Posts: 364 From: San Diego, CA Registered: Feb 2006 posted 10-08-2013 02:38 AM                     Century JJ running 35 - gate band pressure dialed all the way clockwise - some cartoons and trailers are mostly steady on the screen, while others still jitter in the gate pretty seriously. Time for a new set of bands, is it?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 10-08-2013 03:28 AM                     Trap probably isn't aligned. Turret or single lens?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 10-08-2013 07:26 AM                        JJ's are especially sensitive to the "gate closure amount". that is the fully closed position of the gate. Does it just "kiss" the bands or does it bottom out squeezing the band tight against the rails that hold the aperture plate? This is adjusted by the four large screws that hold the gate knob assembly to the mainframe. They are slotted holes and have wandered a bit over the years. They are quite sensitive vertically so be sure to leave them square or you will have focus problems. If they were full forward, you could have the problem you describe. I am assuming that the alignment of the lateral guide roller to the intermittent sprocket is right, just as Brad mentioned. Louis  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-08-2013 09:39 AM                     And there IS actually a distance spec for that and it's best set with a gauge block so you can be sure the gate is set absolutely parallel to the trap... I am pretty sure it's in the manual. Louis????  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 10-08-2013 10:50 AM                        If some prints look better than others, part of the issue at least could be in the films themselves. Are the wobbly ones mainly older (and therefore slightly shrunk) acetate prints?  |  IP: Logged Jim Henk Master Film Handler Posts: 364 From: San Diego, CA Registered: Feb 2006 posted 10-08-2013 11:10 AM                     Single lens, some stock as recent as a trailer for Midsummer Nights Dream (Kevin Kline version), will have a close look at the manual when I get home tonight, gauge block? Gonna have to look that tool up... Much to examine. Thanks!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-08-2013 11:49 AM                     The clearance on the SA was set to .250 for acetate film between the actual bronze casting of the trap and the flat plate the curved runner is screwed to. I do know the JJ is different...  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 10-09-2013 06:48 AM                        We used a long 1/4 inch allen wrench for the SA.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 10-09-2013 08:30 AM                     quote: Jim Henk gauge block? Gonna have to look that tool up... Much to examine. Rectangular blocks of steel ground and lapped very accurately flat, parallel and to size. Several different grades are available and the higher grades are very expensive; the normal 'workshop' grade are affordable, but not cheap. Often known as 'slip gauges'.  |  IP: Logged

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