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Author
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Topic: Enlarging a gate for 16mm Scope?
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Claus Harding
Phenomenal Film Handler
Posts: 1149
From: Washington DC
Registered: Oct 2006
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posted November 18, 2007 11:01 PM
Hi Again,
Not being much of the engineering type, but definitely of the curious kind, here is a question:
Would enlarging an Eiki SSl-type gate be something feasible and worthwhile?
Here are the basics: I am now running an Eiki 3500-series with a good anamorph in front and I would love to see a more 'true' 'Scope image, given what is on the film.
With 16mm locked into the 2:1 ratio, it would be nice to get some leverage on films so you wouldn't have quite as severe a 'width-vs.-height' issue regarding the frame right from the gate, if the printing of the film permits.
I'd be happy to take a gate from one of my SSls and get more headroom if possible. I am assuming something like a Dremel-tool, to grind things with precision might be the thing, but you tell me.
My main concern is not to do something that leaves burrs or imperfections that would scratch the film.
Best,
Claus.
--------------------
"Why are there shots of deserts in a scene that's supposed to take place in Belgium during the winter?" (Review of 'Battle of the Bulge'.)
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John Whittle
Jedi Master Film Handler
Posts: 791
From: Northridge, CA USA
Registered: Jun 2003
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posted November 19, 2007 09:24 AM
Claus,
Don't attempt to widen the gate. First what's one the film? It's the SMPTE standard of .284 x .380 and it's the 1.33 aspect ratio. Your scope lens has a compression ratio of 2x which means it will expand the picture by a factor of 2.
There is no more information on the film and what you have in fact has been cropped from the 35mm original which is 2.39:1. The first 35mm Cinemascope pictures were 2.55:1 but when the optical track was added, image area was reduced in width and the picture was changed. Over the years this standard has changed slightly since early scope pictures when shown in their full ratio would show splice lines on the screen.
As for the Eiki aperature. You'd need a small hard cutting stone (National Camera was a source when they were in business) and you would have to work very slowly and constantly check your results on screen to make sure you didn't wind up with slanted edges.
It's common practice in 35mm to "file aperature plates" but these are undersize and used to match the projected image to screen size and normal result in a picture actually being less than what's on the film but fitting the screen. This was very important when running a dual projector booth and you had to change lenses and aperature plates when going between 1.33, 1.85, and scope. And you had to change screen masking as well.
As far as I recall, in the portable projector line, there was only one version of the Bell & Howell 302 magnetic sound projector which had an adjustable aperature plate for 1.85. It was either the "K" or "L" but everytime I see one on ebay with good pictures, I can't see the little lever on the top of the aperature plate that changed the top and bottom size. Also since the B&L didn't have optical framing, you had to adjust the aspect ratio and then re-frame and often readjust the tilt of the projector. This whole effort was not for scope, but rather hard matted 1.85 prints which were few and far between.
John
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Claus Harding
Phenomenal Film Handler
Posts: 1149
From: Washington DC
Registered: Oct 2006
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posted November 19, 2007 01:30 PM
Maurice and John, thanks for your responses.
I didn't write this quite the way I thought about it; what I had in mind was the height of the gate, not the width.
Unless I am missing something here, with a working ratio in 16mm of 1:2.66, the print in question ('The Bounty', 1984; shot in 1:2.35) would have to be matted off top or bottom when made to maintain the extra width for 16mm.
However, when moving the framing lever, there is some more picture information before I hit the frame lines, so hence my question, to try to re-establish as much of the height as possible. Or is this a wild goose chase ![[Smile]](smile.gif)
How did we get to have one 'set-in-stone' aspect ratio in 16mm when it came to scope? Or were variations made?
Claus.
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"Why are there shots of deserts in a scene that's supposed to take place in Belgium during the winter?" (Review of 'Battle of the Bulge'.)
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