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Author Topic: Why makes the edge of a print more prone to have lines? Alan Gouger Jedi Master Film Handler Posts: 501 From: Bradenton, FL, USA Registered: Jul 2000 posted 06-06-2007 09:39 AM                        I am mostly talking used prints but what is it that almost all scope prints have lines on the extreme edges. The print can be like new in every other sense. I do not see any projector or transport design reason for these lines. I do not see how miss handling can predictably cause lines on the edges. Whats causing them ?  |  IP: Logged Jeremy Weigel Phenomenal Film Handler Posts: 1062 From: Edmond, OK, USA Registered: Mar 2007 posted 06-06-2007 10:11 AM                     With "used" prints it would be most likely due to someone breaking down the film at too high of speed. The film guides can't spin fast enough past a certain amount of speed since they rely on friction from the film. Once the film is coming off the platter at a faster rate than the friction can keep a "grip" on the film the film begins to glide over the guide surface.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 06-06-2007 11:00 AM                        I think the cause is more likely platter rollers (or other rollers) not turning properly.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 06-06-2007 11:48 AM                     It's usually pad rollers not adjusted properly or failsafes (the older 80s type).  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-06-2007 02:44 PM                     ...and shouldered rollers... -Monte  |  IP: Logged Frank Dubrois Jedi Master Film Handler Posts: 896 From: Cleveland, OH Registered: Mar 2005 posted 06-06-2007 04:12 PM                    ...another vote for pad rollers.  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 06-07-2007 06:38 AM                     Well, since Monte posted a picture of it, I'll ask. What is the point of those rollers? I never understood. Most of the Christie machines I used to service had those as their pad rollers.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 06-07-2007 10:39 PM                     So did older Simplex/Century projectors too Ken.  |  IP: Logged Alan Gouger Jedi Master Film Handler Posts: 501 From: Bradenton, FL, USA Registered: Jul 2000 posted 06-07-2007 11:39 PM                        Thanks for all the replies. The picture of those rollers looks like the same as what my projector uses. Im not doing anything high speed through it though but I can see where if those were used on a transport at high speed it could be an issue.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-08-2007 02:12 AM                     I need to add this comment on my pict: this pad roller came from the middle pad roller assembly which this roller is mounted on the front of the pad roller arm and this roller is holding the film as it leaves the intermittent sprocket to the middle constant speed sprocket. If the lower loops are built too small, the inside of the lower loop is what is making contact with the inner shoulders of this particular roller and doing the base side scratching. Chek with your local supplier for non-shouldered rollers to replace these shouldered rollers for your make of machine. -Monte  |  IP: Logged Peter Mork Expert Film Handler Posts: 181 From: Newton, MA, USA Registered: Jun 2002 posted 06-08-2007 03:02 AM                     I agree. I've long since replaced all those double-flanged rollers (or whittled off the inside flanges) wherever I found them, and never had a problem as far as them keeping film in place. Maybe the idea was to give an extra bit of insurance when running beat-up prints with nicks and split-off edges - something you don't see much in the polyester era.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-09-2007 11:56 PM                     I do believe that the shouldered roller concept came from the nitrate era - to keep the film securely centered on the sprocket since the constant speed sprockets on those early machines travelled a lot faster in rotation speed (16tooth) and a tighter film wrap making it prone for film hop off the sprocket. The 24tooth XL sprocket was a blessing in the long run by slowing down the rotation speed and making a larger film wrap around the sprocket, thus less curve stress on the film. Also, those early machines had brass pad rollers equipped with the same inner shoulders.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 06-10-2007 08:48 AM                        Monte; remember the tps (teeth per second) is the same! Louis  |  IP: Logged

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