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Author Topic: Strong Millenium heat shield/shutter contact Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-24-2007 09:44 PM                     The published figure for the DP-70 is 54%. As for the other two its pretty simple and not very confusing although neither projector has an actual published spec... But to get the same efficiency as the Simplex Christie sped their shutter up and it is closer to the film by 50% than the Simplex shutter. Anyone here that can't see what they did to make up the difference is blind as a bat! Mark  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 10-24-2007 10:05 PM                       As I remember, this projector had a reputation as a light sponge. The bronze gearbox also could not stand any heat so the next step in a long line of fixes was to eliminate the gearbox with the twisted belt and essentially the same bow tie shutter with pretty low rotational speed. Somewhere along the way it went to a one wing shutter to improve the output. All else being equal, the Christie should put out as much light as out beloved DP70, but we know it does not.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-24-2007 10:45 PM                     You and Steve seem stuck discussing things that haven't existed in the Christie world for over a decade. Mark  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 10-24-2007 11:31 PM                       Like I said, the whole topic is absurd, like who makes the best wagon wheel. It is very hard to forget a projector that had such humble beginnings and has so much to be humble about.  |  IP: Logged Bryan M. Montgomery Film Handler Posts: 47 From: Chillicothe, Ohio Registered: Jul 2007 posted 10-25-2007 01:28 AM                        Lose the baffle, or keep it? Is it possible to get a consensus? I have already moved the baffles to the rear of the L-bracket like you said Mark, and they still make contact at times. One thing I forgot, I only have this problem with our projectors mated to 3K lamphouses. They are the only fussy ones.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-25-2007 04:14 AM                     Interesting that you still got 'shutter ping' coming from that moving. Wonder, if that baffle then is warped to where the leading inside edge is so warped that it's pinging the face of the shutter still. When you took it off, did you have to straighten it some?  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-25-2007 07:38 AM                     Not only can that baffle warp but so can its mount and the entire back plate that the mount goes onto as well as the shutter housing... humble schumble oei vie! Its not really as common on newer machnes but the plague with the old black ones since none of those castings were heat treated.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 10-25-2007 08:15 AM                     Do you have water cooling, by any chance? Those cooling tubes on the Simplex get routed over the intermittent and come VERY close to the shutter. As to Christie...I've been in a single complex, doing studio screenings and had mix of both shutters. Mark, you seem to look at the things that interest you and ignore the rest. The Simplex shutter cuts the aperture nearly square...the same can not be said of non-conical shutters, period. While, yes the smaller cone of light that Christie is cutting does go towards their efficientcy, I have yet to find that the single-wing Christie is as light efficient as either the DP70 or the Simplex...but more on the order of Century. However, as the shutter moves closer to the film plane, the shutter also moves into the focal point of the lens and will have a more pronounced flicker to come with it...you can even see it with Simplex as compared to Century...that is Simplex has a pulsation to its image that Century does not. As to DCinema...sure it is coming in at the moment but it does not negate the issues of film in the present day. I, for one, am still installing mostly film systems with video augmentation. Steve  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 10-25-2007 10:33 AM                       I'm not so sure the pulsating is due to the closeness of the shutter to the film. It's there, but why is not proven.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-25-2007 01:05 PM                     only time I see that pulsation is if the bulb focus is a bit too close ..and the pulsation is really noticable on the end credits. That tells me to back the bulb up a bit to where the light just begins to dim on the screen.  |  IP: Logged Bryan M. Montgomery Film Handler Posts: 47 From: Chillicothe, Ohio Registered: Jul 2007 posted 10-27-2007 01:47 AM                        You guys are killing me...  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-27-2007 03:33 AM                     Welcome to Film-Tech! You get tons of information here.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 10-27-2007 08:16 AM                     Sam, I'll conceed there is no study that out and out proves a pulsation that relates the shutter to aperture...however, it certainly passes the "duck test." Find a shutter in close proximity to the aperture and the image will generally have a pulsation. I am rationalizing that the shutter is closer to the focal plane and is therefore being observed opening and closing. I don't see this same thing on Century projectors where the shutter is notably farther away and creates more of a dissolve. Monte, the pulsation we are referring to is not the same as an over focused lamp...every Simplex XL or later exhibits it (as to Christies). It is most easily perceived on end credits (white letters on black backgrounds). Haven't you ever played "name the equipment?" Go into a theatre you are unfamiliar with to watch a movie and predict what they are using by just using your eyes and ears watching the movie...after the show...see if you were correct. Some projectors have "tells" and Simplex, Christie and Century definately have them. Likewise with speakers...they may look alike on an analyzer after tuning but I can tell you when I'm hearing an EV DH1 compression driver rather quickly. Likewise with the various digitals...I still find it unsettling that I like the sound of SDDS the best overall. Steve  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 10-27-2007 09:34 AM                     quote: Steve Guttag Mark, you seem to look at the things that interest you and ignore the rest. Steve, Thats hardly the case... If you read back you'll see that I agreed that the bow tie Christie shutter was a problem and does flicker. However I tend to live in the present(at least on my customers behalves) and not in the past which as far as the Christie you seem to be best at. Christie uses and has now for over 10 years a double speed single blade shutter and not a bow tie version. If you have customers with GP machines and haven't been converted to single blade shutters do them a favor and do so, its an inexpensive conversion and image quality goes from a 5 to a 9.5. The flicker problem of the bow tie shhutter is why they went to the single blade version and it got rid of all the annoying flicker problem. At least for myself I have but one P35C single blade shutter machine left running and gobs of 35GP's that have all been converted to single blade if they didn't have them. Also, Your claim of the shutter cutting the aperture squarely stands with no proof of relationship to light efficiency, in fact I'll say it has way more to do with velocity then the angle of attack. If you look at the DP-70 shutter blade which is also VERY close to the film plane it is clearly the highest velocity blade of the bunch you'll find that it cuts the aperture somewhat diagonally but it still is the most efficient mechanically based shutter with a published spec of 54%. Another interesting projector with an annoying flicker problem was the Motiograph AA. Either its double or single shutter versions both had a similar flicker problem. Motiograph even admitted this but was never able to do a "fix" for it because they thought the problem lie in "lost Motion" in the 21 pair gear train. Interestngly both the AA versions used drum shutters that ran at the same velocity. The double shutter was abandoned both because it didn't do anything to get rid of the flicker and it was difficult as hell to replace the double shutter bearings. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 10-27-2007 09:58 AM                     Mark, all the single blade shutter did was reduce the flicker (and double the velocity which improved efficientcy)...it did not eliminate the flicker. I don't live in the past but certainly work with much that is in the past. I tend to put in most of the latest and greatest too. I'm dying to meaure the new Kinoton Premier shutters...they look to be substantially more efficient than 50%! Their improvements come from a faster intermittent allowing a shorter closed time. The blades are just over 80-degrees.  |  IP: Logged

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