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Topic: (Travel) Ghostbusting this Halloween

John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 10-28-2003 12:57 PM

In this thread:

http://www.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=4;t=000669

Don Anderson wrote about travel ghost:

quote:
Some credits are nice and crisp, while others are overburned ( I guess thats the word I'm looking for). But, you are right about the ghosting. I had a few people walk out 3/4 way through the film, saying ...."why would anyone one pay to see this s#@!. But, hmmmmm, they did pay to see it

I replied:

quote:
Of course, travel ghost (the shutter not completely blocking the light during film pulldown) is most visible on white titles against a black background, like closing credits. It's usually more visible on the right hand side of the image. If you see travel ghosting, by all means adjust the shutter timing or consider changing the shutter to a larger blade. Be sure you do not have excessive "play" in the gear train between the intermittent drive and the shutter shaft. If I see travel ghost anywhere, I bring it to the attention of the theatre so they can fix it.

Being Halloween week, do any others have tips and techniques for evaluating and fixing "Travel Ghost" problems?

Other than simple timing problems, insufficient shutter blade size, and excessive play in the gear train, has anyone encountered unusual sources of "travel ghost", such as a shutter blade warped or burned by excessive radiant energy?

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Dean Kollet
Jedi Master Film Handler

Posts: 591
From: Florida State University
Registered: Jul 2003

posted 10-28-2003 02:21 PM

people walking out the ghosting was that bad? We have had circumstances where the ghosting was horrible but you could only really tell when words where on the screen (beginning and ending credits). I'm not very knowledgable about projection yet, but we adjust the ghosting knob or we check to see if the shutter blade is intact, especially in our 7k house...

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 10-28-2003 02:40 PM

quote:
We have had circumstances where the ghosting was horrible but you could only really tell when words where on the screen (beginning and ending credits).

Even if the travel ghost is not severe enough to be visible in the picture, I would consider noticeable travel ghost in the closing credits to be "Film Done Wrong" [Frown]

. And most movies have at least a few scenes with lights against a dark background (e.g., car headlights, streetlights, lit buildings) where even a bit of travel ghost would be distracting. [thumbsdown]

Hope you can get it fixed ASAP.

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David Stambaugh
Film God

Posts: 4021
From: Eugene, Oregon
Registered: Jan 2002

posted 10-28-2003 05:56 PM

I find travel ghosting *very* distracting. Nip it -- Nip it in the bud! [Wink]

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 10-29-2003 06:44 AM

Ghost in the top half -- shutter is late

Ghost in the bottom half -- shutter is early

...or is it the other way 'round?

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 10-29-2003 08:18 AM

Ghosting above titles or other item of interest means you're seeing the frame leave the gate (downward film travel projecting upwards on the screen due to the lens flipping the image) which means the shutter is late and didn't hide the image before the film travel began. Ghosting below means the shutter is early as you are seeing the image projected just as the film is coming to a stop.

Ghosting both above and below means you have an undersized shutter blade incapable of hiding the entire pulldown period or some lamphouse vs. projector issues where the physical size of the shutter blade is unable to completely block the cone of light.

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 10-29-2003 08:34 AM

If the severity of the ghosting seems to waver, coming and going, check for excessive play in the gear train between the intermittent drive and the shutter shaft. If it is perfectly constant, it's likely due to incorrect timing (ghosting above OR below light areas), or insufficient shutter blade size (ghosting above AND below).

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 10-29-2003 12:08 PM

Also if the projector is belt drive check belt tension

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Travis Hubrig
Expert Film Handler

Posts: 175
From: Minot ND, USA
Registered: May 2003

posted 10-30-2003 03:19 PM

From time to time I will make a new test strip for checking timing (travel ghost)...

I will cut the credits from a few old trailers, it is very easy to adjust when looking at the dark background.

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Ken McFall
Jedi Master Film Handler

Posts: 615
From: Haringey, London.
Registered: Apr 2001

posted 10-30-2003 03:55 PM

Simple way to remember how to adjust the shutter is BRAT...

Bottom Retard, Advance Top. One of those silly little things I was told many years ago by a seasoned engineer that has stuck with me.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 10-30-2003 05:42 PM

Even easier...trails up, turn shutter blade up...trails down turn the blad down.

Steve

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