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Topic: Wavy lines

Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 08-03-1999 05:13 PM

I have a question:
What the hell are those horizontal wavy lines that sometimes come and go on a certain reel of some movies? I assume this is the labs fault, so why hasn't anything been done to correct this? I was told by one guy that it was caused by a guy at the lab wearing a striped shirt! Yeah, that must be it =P
It annoys me greatly and I'm sure annoys the audience as well. It must be stopped.

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Gordon McLeod
Film God

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

posted 08-03-1999 05:21 PM

One cause can be the film winding unevenly so that each layer is at a different hight and then being flattended out by wand in effect puting horizontal cinches

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Christopher Seo
Jedi Master Film Handler

Posts: 530
From: Los Angeles, CA
Registered: Jun 99

posted 08-03-1999 05:46 PM

I think I've seen horizontal cinch marks... sort of like raindrops falling horizontally? But I don't think I've ever seen wavy lines.

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Mike Blakesley
Film God

Posts: 12767
From: Forsyth, Montana
Registered: Jun 99

posted 08-03-1999 07:03 PM

I think he's referring to a lab problem. It isn't scratches...it looks like a wavy pattern of darker/lighter that moves down the screen for brief moments. Looks almost like a cinema version of TV interference would.

I've noticed this happening more frequently lately...thought there was something wrong with the projector at first, but it happens only on certain movies and only at certain moments, so its gotta be the film.

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Gordon McLeod
Film God

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

posted 08-03-1999 07:45 PM

One thing I have found as also distracting is when you get the image of the heat pattern from the xenon lamp showing up in a bright scene

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Gordon McLeod
Film God

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

posted 08-03-1999 07:46 PM

One thing I have found as also distracting is when you get the image of the heat pattern from the xenon lamp showing up in a bright scene

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Mark Ogden
Jedi Master Film Handler

Posts: 943
From: Little Falls, N.J.
Registered: Jun 99

posted 08-03-1999 08:20 PM

I think I know what you're talking about, this turns up on "Runaway Bride" about the fourth reel or so, the scene where Julia Roberts and Joan Cusack are having a talk in the beauty parlor, it's just that one scene. I have no idea what this is, it can't be a printer problem because it's just that one sequence. Trouble in the original photography? Maybe a problem with the camera shutter? Hard to belive, but possible, I guess. Look carefully and you'll see a wavy light-dark-light waterfall effect throughout the scene (unless it's just us, but we've got two
prints and it's on both in the same scene). Anybody else see this?

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 08-03-1999 08:42 PM

I know exactly what you're talking about. It drives me crazy. I've got a trailer where the 2nd half of the green band is like that. Talk about annoying! It was Star Trek 7...so that gives everyone an idea of how long this has been going on.

It looks like an old tv antenna with bad reception with rolling lower contrast lines. Typically it only lasts for several seconds, but it is highly distracting. It is definitely a lab problem as I've never seen it on two prints of the same movie in the same spot. The most recent one I've noticed it on was Thomas Crown Affair.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 08-03-1999 11:37 PM

I noticed this one one of our prints of Runaway Bride as well, towards the end. I haven't checked out our other print. Does this happen on Fuji film stocks?

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John Pytlak
Film God

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

posted 08-04-1999 09:27 AM

Joe contacted me directly on this, and reading the other postings now gives me enough information to indicate that the horizontal wavy lines are probably "printer bars". In a contact printer, the negative and print film are brought into contact on a 64-tooth printer sprocket, and exposure occurs via a very narrow slit of light coming from the additive lamphouse. If the printer speed varies slightly, or there is slippage on the sprocket, the exposure time varies slightly as the film is transported past the slit of light, causing faint horizontal density bars. These printer bars are most apparent in scenes that were underexposed, since the printer aperture needs to close down for these light negatives, narrowing the slit of light even more. They will definitely be scene and printer dependent. If you can provide details (feature name, print number(s), reel number(s)), Kodak can get back to the lab and work with them to adjust the printer.

------------------
John Pytlak

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 08-04-1999 02:02 PM

Thanks for the lab info, John! I don't think there's anyone here who has done any serious motion picture printing work, so the info is much appreciated.

I will start taking notes on this occurence. I have noticed it to be less frequent as of the last year or two, but it still pops up nonetheless. (Wish I could remember when it happened in that print of Runaway Bride I screened.) If anyone sees this, post the info here. Perhaps Mr. Pytlak can take such info to the labs and assist in taking care of this problem.

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David Stambaugh
Film God

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

posted 04-16-2002 10:11 AM

This topic came up in the review thread for "Changing Lanes"; bumping it up. I notice this wavy, rolling line thing in maybe 1/3 of the movies I see. The print of "Changing Lanes" I saw definitely had it. Many others still do as well. Surprising that it doesn't get mentioned more often here. If I notice this in the future I'll try to remember to mention it in my "reviews". The first time I noticed it I thought it was a projection problem, but that clearly isn't the case.

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John Pytlak
Film God

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

posted 04-16-2002 12:55 PM

The "Changing Lanes" description of looking like a faint "roll bar" on a CRT display seems to fit the "printer bar" or "flutter bar" explanation. Was it most apparent in scenes that were underexposed (e.g., the scenes also tended to have low density "milky" or "smoky" blacks)?

"Flutter Bars" are described in the book "Motion Picture Film Processing" by Dominic Case, Focal Press Media Manuals, ISBN 0-240-51243-X, page 100.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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David Stambaugh
Film God

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

posted 04-16-2002 01:07 PM

Since I have nothing better to do today (I'm still a downsized unemployed loser, 6 months now...), I may go see "Changing Lanes" again, but at a different theater. I will pay particular attention to 1) Focus, and 2) Wavy Lines.

Hopefully Cinemark hasn't banned me for life yet. "No soup/movies for you!"

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John Pytlak
Film God

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

posted 04-16-2002 01:21 PM

Try to notice if the scenes most affected with the "rolling bars" also tend to be lower in contrast, with "smoky" blacks and more grain --- typical signs of underexposure. As I noted, underexposed negatives are much lower in density, making the printer reduce the light beam used for printing to a very narrow slit, so even the slightest speed variation in the printer shows up as a faint density variation "bar" across the image.

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