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Author Topic: What would cause this kind of damage to a film? (pictures) Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 10-26-2005 02:43 PM                     Brad, so do I understand this right, what this accomplishes is that the kelmar rubber doesn't touch the film? That's what it appears in the pic.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-26-2005 03:47 PM                     What it kinda looks like converting over to a "Cinemeccania-type" unit to where the lateral guide roller flanges are the only thing contacting the film,in as well as pressing down on these edges of the film to keep the film tension over the scanner drum, thus eliminating any roller contact("treadmarks") in the picture (emulsion) area. Course, the next question would be on this conversion is that if a print that was FG'd, would the print want to slip around the drum since there is no pressure to keep the print in contact with the drum with the removal of the larger rubber roller? I bet that one could go down to an auto part store, buy some gas line neopene hose to do this conversion with. How close am I? -thx Monte [ 10-26-2005, 06:13 PM: Message edited by: Monte L Fullmer ]  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 10-26-2005 09:40 PM                     Both of the above posts are on the money. This way the pinch roller simply becomes a spacer and tension is maintained by the roller just before the holdback sprocket. And yes it works just fine and dandy with FG'd prints.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-27-2005 01:20 AM                     Thus, the viscous dampened snub roller behind the lower pulldown sprocket is keeping things snug around the drum to maintain the tension. Once again, a "Cinemeccanica wannabe" trick...-pretty slick. Now, next question: we know how "5-star" heads, when they start, the film gets a little crazy (wanders back and forth some) until the scanner drum spins up to speed to even things out. With this conversion, does this "craziness" gets eliminated? Going back to the 3rd picture: With my mentioning of the "shouldered" roller, here is a roller pulled from that middle constant speed sprocket pad roller assembly. As you can see, where the sprocket teeth passes through, are these two shoulders - the inner one and the outer shoulder which is part of the outer flange. This shouldered roller was located in the front part of the assembly (which was removed to be replaced with a non-shouldered roller). The picture below is what happens durng film travel between sprocket and roller (with me making the loop and resting the roller over the loop), and you can see how the inner shoulders are making contact with the film (base out) as if the film was passing over a sprocket and under the shoulders. thx-Monte  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 10-27-2005 03:10 AM                     Nice pictoral explanation Monte. Anyone running those kind of pad rollers really needs to replace them with the type that doesn't have that inner flange. Monte, I found that post-modification ALL of the issues went away, including warble from an idler roller with a flat spot on it.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-27-2005 08:13 AM                     I have had more grief from the pad rollers without the inner flange allowing buckling and scratching than with those the important point is the 2 fim thickness clearance  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-27-2005 01:03 PM                     True, there is the two film thickness with the arm rollers, but this roller is from the front of the arm when receiving the loop from the intermittent sprocket. Thus, if the loop is a bit too small, the loop is touching the roller first (and the shoulders) before being pulled down by the sprocket. Why the front roller should be the non-inner shouldered variety on this one arm. Others are okey and I can see the potiental problem(s) as mentioned with the non-shouldered rollers. -thx Monte  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 10-28-2005 09:22 AM                        1, The inner flanges cannot be adjusted not to scratch; should either be turned down or discarded. 2. Brad's modification may work well enough on a 5 star. However, even though the same parts are in use, this will not work on a SH-1000, XL or RCA soundhead. My concern for any modification of this kind is that the wow & flutter content is affected. On a Simplex, which has no Davis loop, w/f is already more than discernable. Worse is unacceptable. Louis  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-28-2005 01:14 PM                     quote: Louis Bornwasser this will not work on a SH-1000, XL or RCA soundhead.... ... since you don't have a tension roller to keep things snug being that the lower roller is designed as a snub roller than with these earlier models being that they have no other form of snubbing the film outside of the pressure roller doing the job of snubbing the film. You'd have W/F like nobody's business without any form of snubbing. -Monte  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 10-28-2005 01:40 PM                     Odd, who was it that said this??? quote: Brad Miller Maybe more people will listen and heed my advice running 5 Star models to do the pinch roller modification to prevent this. Older RCA type soundheads will forever be a shitty soundhead though, as there is nothing that can be done to it's design to fix it. Just giving you boys a little crap. Louis, in every instance I've done this I have achieved a better result, but then again I have not tried comparing it to a brand new pinch roller. It's possible it may be slightly higher, but even so, it sounded great on the machines I converted and when comparing it to the film damage that occurs when running film on these machines, it was a no-brainer. The question is would it work with 5 Star SRD basement readers? Maybe Louis could have one of his guys do the mod and report back since he has a perfect facility and staff to do this?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-28-2005 03:34 PM                     quote: Brad Miller The question is would it work with 5 Star SRD basement readers? Maybe Louis could have one of his guys do the mod and report back since he has a perfect facility and staff to do this? I could give this a try since I do have a Component Engineering basement reader mounted in my 5-star head at my theatre and make the report to all. -Monte  |  IP: Logged Jon Miller Jedi Master Film Handler Posts: 973 From: San Diego, CA, USA Registered: Sep 1999 posted 10-28-2005 07:50 PM                     quote: Monte L Fullmer You'd have W/F like nobody's business without any form of snubbing. I performed the modification on the SH-1007 X-L soundhead on my home setup and on an RCA 9030 which preceded the X-L head. As long as I thread up with just one sprocket hole of slack, the lateral guidance assembly provides a little snubbing action and I hear very little flutter, if any. Allow more slack and the sound turns a fluttery mess and I can feel the lateral guidance assembly shake. Odd.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-28-2005 09:19 PM                     the principal of the slack loop design is that there is 3 perfs of slack so the double flywheel can damp out both the wow and the flutter components  |  IP: Logged

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