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Author Topic: Simplex PR 1050 Gate/Trap Tension Michael Elam Film Handler Posts: 84 From: Clarksville, IN, USA Registered: Mar 2001 posted 08-18-2005 02:55 PM                     On a Simplex PR 1050, what is the best way to determine how tension is to be on the Gate/Film Trap? Just enough to keep the film still?  |  IP: Logged Dan Lyons Jedi Master Film Handler Posts: 698 From: Seal Beach, CA Registered: Sep 2002 posted 08-18-2005 03:06 PM                     Run your loop of RP-40 and slowly increase your tension until image is steady.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-18-2005 03:12 PM                        quote: Dan Lyons Run your loop of RP-40 and slowly increase your tension until image is steady. That's fine, but I really suggest optimizing the tension for each film you run, as things like process machine drying conditions and the age of the print can affect the optimum setting. Yes, slowly increase tension until steadiness is good, then go no higher. If you have to use very high tension, something else may be wrong.  |  IP: Logged Dan Lyons Jedi Master Film Handler Posts: 698 From: Seal Beach, CA Registered: Sep 2002 posted 08-18-2005 03:49 PM                     quote: John Pytlak That's fine, but I really suggest optimizing the tension for each film you run You've got to be joking. That would be reasonable if someone was going to be running an old brittle 4-track mag print (anyone who would ask about this wouldn't or shouldn't be running that type of thing to begin with), but I'm pretty sure the question here was about setting the tension for poly prints at your run of the mill multiplex.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-18-2005 04:02 PM                        It's a "suggestion" for getting optimal quality. You "tweek" focus when you start each feature, don't you? How long would it take to "tweek" the tension too?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-18-2005 04:17 PM                     is your trap and gate assembly, the flat gate style, or the curved gate variety? If the curved gate, you'll have to watch out for excessive band wear, especially at the top of the bands where the upper loop can make contact when the film enters the trap. I always maintain the tension knob at the "1" position for curved gates. Flat gates can be variable if needed. Now, if you're having trouble with picture steadiness and having to send the tension up to the max, the trap and gate assembly has an adjustment for closure. And that adjustment is the gate stop allen screw located on the trap side assembly below and right of the aperture plate . This screw is what stops the gate at a precise point. Adjust this screw to where the gate can close a bit tighter with the setting knob at minumum to where the picture is steady and the film is actually running smooth through the assembly. This is a step method of adjustment-by taking off the gate, adjust the screw a bit, rethread to see if steadiness is there, if not, repeat the cycle until the goal is achieved. -Monte  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-18-2005 04:38 PM                     quote "Run your loop of RP-40" there is no such thing as a loop of RP40 The test film in question is 35PA Also it is on BW stock typically and a different sprocket pitch so again it isn't the best choice Also there is differences between print runs and labs for the amount of moisture in the print and also the amount of lubrication so it needs to be adjusted on a per print basis The minimum tension required to maintain focus and steadiness is all that is wanted  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-18-2005 04:48 PM                     Nope, John was not kidding...tension should be checked on a print by print basis with the lowest tension needed to do the job. On a Simplex and Century with just 5 detented positions this might seam crude but on other brands, the tension is quite variable and in the case of a Norelco AA2, can be easily mal adjusted when the gate is opened. As to setting gate depth as a form of tension adjustment...that is just plain silly. Generally, without binding the film, you want the gate as close to the aperture but allowing for the film to swell such that it never can blister into the aperture plate. With higher wattage lamps, about 1/8" is a good starting point, with smaller lamps a closer gap can often be had but make sure you don't bind the film as it exits or enters the gate. The closer you get the gate to the aperture (again with out binding or blistering the film) the less of a "fringe" area you will have and less bleed on the masking. Tension bands don't come into play on this...depending on the projector, there are other tricks of the trade to get them optimised and for Simplex and Century, ideally set to "1" for most films.  |  IP: Logged Gordon Bachlund Jedi Master Film Handler Posts: 696 From: Monrovia, CA, USA Registered: Aug 1999 posted 08-18-2005 05:38 PM                        RP 40 is the specification for 35-mm Projector Alignment and Screen Image Quality Test Film.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 08-18-2005 06:23 PM                     Yes, but RP40 can refer to both 35PA (black-and-white) and 35IQ (on color stock). --jhawk  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-18-2005 06:28 PM                     actually it isn't can but does refer to the use of either test film the point being there is no RP40 test film  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-18-2005 08:13 PM                     quote: Dan Lyons You've got to be joking. Well the Simplex(Pile-O-Pot Metal) trap/gate is quite crude but it can work well if one pays attention to what you are running through it. Not only does the trap band tension adjustment affect steadiness it also can affect how well the image focuses on the screen. Merely running a tst loop won't do much good. You have to pay attention to the film you are running through at any given time and get used to how your particuluar machine behaves and then set it to achieve best steadiness and flatness of focus. I find that normally the tension knob will lie somewhere between the first and third click stop. Mark  |  IP: Logged Dan Lyons Jedi Master Film Handler Posts: 698 From: Seal Beach, CA Registered: Sep 2002 posted 08-18-2005 10:28 PM                     So we should all "ride" the tension knob and also adjust for each trailer we run. quote: Gordon McLeod Also it is on BW stock typically and a different sprocket pitch so again it isn't the best choice I've run two features printed on stock with that type of sprocket pitch in the past year, both ran just fine and looked good on screen.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-19-2005 02:03 AM                     quote: Dan Lyons So we should all "ride" the tension knob and also adjust for each trailer we run. ..I've done that a few times...sometimes with old acetate stock, and "green" prints. There is no such thing as perfect film just as there is no such thing as a perfect machine, for each roll of stock (or even emulsion) could be a few microns difference in thickness, but generally most machines, if adjusted correctly can "forgive" this difference of thickness per each roll. -Monte  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 08-19-2005 06:16 AM                        I've run a number of Century "C" projectors that give a perfectly steady image at the minimum tension setting possible (without removing the nuts completely). Is this a sign that something is wrong with the gate/trap assemblies? (On the other hand, Century JJs running mag 70mm _definitely_ require tension adjustments for every film and, sometimes, every reel of every film.  |  IP: Logged

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