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This topic comprises 3 pages: 1 2 3
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Topic: kinoton pk-60 vertical unsteadiness
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Larry Shaw
Expert Film Handler
Posts: 238
From: Boston, MA, USA
Registered: Mar 2000
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posted 08-14-2007 06:16 PM
After a nice vacation I return to see a number of strange comments about Kinotons.
First, note that Mr. Wetzel writes "when i run test film...such as RP-40 the image is stable, however, when an actual movie is shown the shaking is noticable". That of course is a clear indication that the problem is unstable images on the prints, not a projector problem. Also, let me point out that the auditorium in question, which I have visited on a courtesy call, has an enormous screen, perhaps 80' wide. That is why only that one house in the complex has a Kinoton...the previous projector (as used in their smaller screens) looked nasty on this giant screen.
Second, as far as I and my colleauges here and in Germany know, there have never been any Kinoton or Philips coupler interior made of metal of any sort. We also have original vellums of nearly all the Philips parts and the couplers are clearly made of Delrin. If anyone has such a thing I'd love to see it, but I sincerely doubt it ever existed. It is true that some few years ago production of the couplers changed from Philips to Kinoton. This is because Philips, who now is an enormous manufacturer of all sorts of things, just wasn't interested in making parts (framing couplers) for types of products they no longer made. Kinoton now makes the couplers, which are very nearly the same as the Philips-produced ones. Regarding MiT or others making knock-off couplers and the use of "a ten cent part", I have seen the manufacture of the new couplers which include high precision injection molded components as well as the metalwork and individual testing and I can assure everyone that this is not an inexpensive part to make, and that the startup costs to make the first ones would be extremely high.
My experience with lots of these machines gives me insight to to issues related to all this talk of a lowering of stability.
One problem is heat. There is no question that extreme gate tempratures result in less stability. Kinoton has always offered gate cooling kits and water coolers (with actual heat exchangers or chillers; not the inefective pump-in-a-bucket things), and reccomended them over 3kW. Most projection engineers will tell you that running high wattage lamps without cooling is a poor idea on several counts. Some consoles with metal reflectors have particularly high heat output and when run without heat filters are almost guaranteed to produce a poor picture. As lots of theatres now have large bulbs, this is a more prevalent problem.
A second problem is gate tension. Kinoton uses Delrin in the gate because it is a slippery plastic that lets the film glide through the gate more easily reducing film damage and producing a more stable picture. Over the last few years I have seen the following scenario that ends up making the Kinoton gate design look bad due to a lack of understanding. A print comes in that is unstable (due to the giant print orders now common; Deluxe Toronto routinely prints 10-15 million feet a day). The operator tries to correct the movement by increasing gate tension. There is no, or little, change. Either shoulders are shrugged or a new print is ordered (good luck). What usually does not happen is that the gate tension is reduced by the old technique of lowering it 'till there's a bit of jump, then increasing it just a bit. So the gate tension remains very high wearing away at the skate, runner strip and coupler. This same thing happens to all machines treated thusly, but the wear shows up sooner on the Delrin parts. And as Brad mentions, we do make steel runner strips...we also have harder, longer lasting skates. But the real answer is to keep the gate tension at a minimum, something I was taught a zillion years ago as an apprentice.
Theatres that run Kinotons with adequate cooling (water and/or filters as needed) and low gate tension generally have very long lives for their couplers and gate parts. And places like studios and DI facilities use Kinoton projectors with Delrin parts because they want the most stability available. I think the bigger issues here are not equipment quality, but application and operation.
Larry
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Samuel Andrew Wetzel
Film Handler
Posts: 16
From: Appleton, Wisconsin, USA
Registered: Apr 2006
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posted 11-08-2007 12:07 AM
Larry,
Didn't mean to scare you with any comments about kinotons. They are amazing machines...and I did realize that if the RP-40 or schneider test loops run with almost zero bob or weave that the vertical shaking is due to a combination of print problems, heat, and, like you mentioned, the incredible amount of magnification for a 35 mm print. I had to simply plead ignorance because, being the only kinoton in operation here, I didn't know too much at the time about it...and I was looking for ways to minimize the shaking even with the negative factors. Although we have a pretty worthless water circulator, changing the skates and pressure pads frequently, making sure the pad is tight against the intermittent sproket, and keeping it clean keep the shaking to a level unnoticeable by the general public. It was interesting to hear that you've been at our location...must have been a while before I started working here though.
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