This is topic Simplex XL Curved Gate Flexibility in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Steve Scott (Member # 630) on 05-30-2006, 01:16 PM:
We have three XL's from three vintages: Late 50's, late 60's & one that was installed new in 1999. These are all curved gate, PR-1014's. I noticed, on the two older machines, that the round metal pieces which fit against the right-angled tops of the gate bands have some horizontal play to them; whereas, on the new vintage these metal pieces do not move.
Is this a design change by Strong as of late, or do the older machines' gates need repair?
Posted by System Notices (Member # 2357) on 02-05-2012, 09:04 PM:
It has been 2077 days since the last post.
Posted by Victor Liorentas (Member # 5272) on 02-05-2012, 09:04 PM:
Has anyone ever noticed that there are two types of curved pressure pads on the XL?One is curved even from top to bottom and the other curves further close to the intermittent.
I believe the newer design has the slight difference at the intermittent.
Is one better than the other?
I hope to hear something before 6 years passes. ![[Smile]](smile.gif)
Posted by System Notices (Member # 2357) on 03-30-2014, 01:06 PM:
It has been 783 days since the last post.
Posted by Victor Liorentas (Member # 5272) on 03-30-2014, 01:06 PM:
Well only 2 years have passed since the last question. ![[Big Grin]](biggrin.gif)
Lately I have been in discussion with some very knowledgeable lens technicians and there is some controversy about a curved gate design!
This surprised me because I thought it was uncontroversial,curved gate better focus.
The higher lamp wattage , the more benefit but also better at any wattage.
How does everyone feel about curved vs flat gates?
Posted by Louis Bornwasser (Member # 3063) on 03-30-2014, 06:01 PM:
Steadier, sharper picture especially over 1kw.
Posted by Mark Gulbrandsen (Member # 72) on 03-30-2014, 07:21 PM:
In the late 1930's before WW-2 started Kodak did a lot of research into just this question and it is the subject if an article that was featured in International Projectionist of the time. I actually have that issue. They also shot high speed film of what happens to a film frame when the shutter opens and closes. The film actually bulges away from the light source and then falls back when the shutter closes and Kodak engineers managed to come up with a way to measure how much the film frame bulged. They used a Simplex E-7 for the tests. The article was not so much aimed at curved gate vs. straight gate because curved gates were not in use back in the late 1930's plus these tests were done with nitrate film. The idea here was to provide detailed information for optical designers so they could design lenses with adequate depth of field to keep the image in focus.
But today, curved gates beat the heck out of straight gates and they manage to eliminate at least some of that bulge that occurs when the shutter opens and closes. If optical designers you talk to are still favoring straight gates they are living in outer space somewhere. I can't think of a modern cinema projector that has a straight gate.
Mark
Posted by Gordon McLeod (Member # 33) on 03-31-2014, 08:28 AM:
BTH discovered on the Supra machines that curved gates had focus issues as well
Posted by Victor Liorentas (Member # 5272) on 04-01-2014, 12:20 PM:
I was thinking of machining one of my extra curved gate shoes from an XL,shaving a bit of the curve off. I keep thinking perhaps wrongly that less curve would benefit a 2500 watt lamp-house.
It would be interesting to see the result anyway.
Posted by Mark Gulbrandsen (Member # 72) on 04-01-2014, 10:28 PM:
I think the Apogees have a longer gate which means a shallower curve....