Film-Tech Forum ARCHIVE: Filmguard & SR-D

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Posted by Jack Ondracek (Member # 1466) on 08-03-2003, 02:16 PM:

Seems this should be here somewhere, but I couldn't find it. If so... sorry.

John P. mentioned the wear caused by abrasion on the sprocket areas of a print & how it can eventually cause dropout problems.

I imagine Filmguard lessens this abrading substantially, and I'm curious what SR-D users experience... with/without. We're putting a Dolby into one of our screens, so I'm wondering what to expect.

Posted by Steve Guttag (Member # 268) on 08-03-2003, 03:04 PM:

Film Guard with Dolby SR*D is definately a huge + [thumbsup]

If you note what your film is running on the error thermometer when it is new...then run it with a film-cleaner and film-guard as directed (every show, if possible) you will find that within 2-weeks the error number has dropped by as much as 2 numbers! Yup 4s turn into 2s. Yesterday at the Uptown, I noted that Seabiscuit is now running "0" on some areas...not even "0." but a solid "0"

For you Kinoton users out there (or others with delrin contact parts)...Film-guard will generally double to triple the wear life. Normally a Kinoton skate is good for about a year. With Film-Guard used regularly, we are seeing over 2-years!

Since Film-Guard has some of the properties of "wet-gate" printing...that is, it fills in abbrasions, the Dolby Digital reader has less work to do. I think it also helps with contrast so video processor has less work in differentiating between a "1" and a "0" in "bit-speak."

Lastly, if you use Film-Guard on all shows...any debries that may be caused by the sprockets/gate are suspended in the Film-Guard and carried to the film-cleaner on the next pass...thereby reducing the wear yet further since it isn't just left there to grind in again.

I'm sure SDDS and DTS also benefit similarly but I haven' t done nearly as close a study (don't have SDDS at the Uptown and never had an issue with DTS to begin with).

Another nifty benefit I noticed was the Film-Guard acts like a mini "heat-filter"...you are far less likey to blister film that is Film-Guarded...particularly a silver-rich stock like Vision Premier

Steve

Posted by William T. Parr (Member # 677) on 08-03-2003, 03:31 PM:

Jack, I have to second what Steve has said about the error rate. I have 1 Dolby Digital unit in my complex Before we run film guard on the print in there we are seeing 3 and 4's on the error counter. After the second pass of film guard it is down to 2's and 3's. After we get the third run over with we see .0's and 1's consistently so there has to be a lot of truth to the claims of the product, by the way I also have 3 dts and 1 SDDS unit as well and the seem to do better over the life of a picture running with film gaurd than we were before we started using it religiously

Posted by Brad Miller (Member # 2) on 08-03-2003, 03:53 PM:

A few years back I used the QC program and documented Episode I on it's first pass in a certain auditorium with SDDS that had just had a full reader alignment. Then some 4 months later when the print was on it's last week I moved it back into that auditorium which had not been touched in 4 months (but did have 4 month of use on it) and the results were much, much improved. So yes, SDDS benefits just as much as Dolby Digital does.

On my Dolby Digital screens where FilmGuard is ran, 0-2 are common readings, even on the cat701 readers. At the Chinese in Colorado with the Christie basement readers, after getting them aligned most of them would sit at 0-2 and a couple that I could never quite get the alignment ran between 3-5 consistently. When I left and returned a couple of weeks later to visit, the projectionist reported that they were having dropouts on ALL of their SRD screens and a couple of the larger houses were having focus flutter. These were the same operators that worked there for a few months before and the only thing they had changed was they stopped using FilmGuard. Upon looking at the film closely, the gate bands had accumulated hard deposits from the print shedding and had literally laid scratches right into the SRD data blocks. He said they were cleaning the projectors between every show. Of course that doesn't do much to help the last part of a movie as the buildup increased, and skipping the cleaning once or twice would permanently ruin the SRD track.

I don't think dts would really benefit much one way or the other since it is only carrying timecode on the print and not the actual audio data.

Posted by Jack Ondracek (Member # 1466) on 08-03-2003, 04:12 PM:

Thanks for the info!
I figured it would at least slow down any deterioration. I hadn't considered it might actually improve performance over a new, untreated print. I wonder what's with that?

Posted by Brad Miller (Member # 2) on 08-03-2003, 04:22 PM:

It's mostly shipping dust from the dirty reels and the dirty cans, although abrasion of the film from the lab also plays into account.

Posted by Josh Jones (Member # 447) on 08-03-2003, 04:51 PM:

For what its worth, a year or so ago, We played "trainspotting" for one of our late shows. The print was pretty scabby, and the dolby would not track at all. Seeing as how the film was to run another night, I ran home, got my film cleaner and film guard, and put it on the projector the next night. I was pretty thrilled when the processor was reading constant F's started doing consistent 5's, which is this house usually gets 3-5 on the error rate. all this with just one application [Smile]

Josh

Posted by John Pytlak (Member # 331) on 08-04-2003, 08:29 AM:

Although Kodak VISION Color Print film has lubricant in the formula for both back side and emulsion side, for optimum projection life, post-process lubrication is still recommended by the Kodak processing specifications and by SMPTE Recommended Practice RP 151. Proper lubrication greatly reduces projection wear of the print, especially along the edges and perforations where the film can be abraded by the projector gate, intermittent sprocket shoe, and rollers (which happens to be where current bits-on-film digital sound is printed).

Posted by Steve Kraus (Member # 476) on 08-04-2003, 07:43 PM:

We may have talked about this before but do labs do edgewaxing or other lubricating step anymore?

What is the on-screen visual effect of Film-Guard on a first pass?

Posted by Brad Miller (Member # 2) on 08-04-2003, 07:51 PM:

I think John said although Kodak recommends edge lubrication that few still do.

The first application has faint lines that look like water on the image. In your situation being a screening room, if you were to use it you would want to mount the cleaner on your rewind bench and simply rewind the reels through it before showing. Plus that way you only need one film cleaner.

Posted by Phil Hill (Member # 371) on 08-04-2003, 08:10 PM:

While at Iwerks, I did many tests with edge lubrication and generally found it a waste of time and $$$ and not worth the effort.

If a projector is setup correctly and maintained by competent people, there is no reason for it.

We commonly got over 12,000 passes on prints loaded in loop cabinets. The color would fade due to the lamp UV before the media would wear out.

>>> Phil

Posted by John Pytlak (Member # 331) on 08-04-2003, 08:27 PM:

Phil:

What type of projectors? What type of edgewax (e.g., paraffin, carnauba, silicone, Teflon/Vydax?) Concentration? How applied?

The tests and paper Kodak published in the early 1980's showed properly edgewaxed 35mm prints had much less projector wear than unlubricated prints. Edgewaxing has been shown to have significant benefits ever since the early days of the movies. (See the 1920's publication "Film Mutilation" that Brad just posted on Film Tech).

Posted by Phil Hill (Member # 371) on 08-04-2003, 08:42 PM:

John, All types of lubes...

The projectors were Iwerks' modified Ballantyne 870's and Pro35 projectors.

BTW: these tests were conducted in the late 90's and did not rely on any old Kodak "papers".

The hastle was just not worth it in our findings...

>>> Phil

Posted by John Pytlak (Member # 331) on 08-04-2003, 09:04 PM:

I'm sorry that you feel 80 years of practical experience (including Kodak technical "papers") are irrelevant. Your lack of problems is a tribute to the lube that Kodak is able to put in our print film. [Smile]

But proper post-process lubrication would have improved print life even more, especially along the edges and in the perforation area that are heavily abraded by some projectors.

Did iWERKS print any digital sound or data that would be subject to projector wear in those abraded areas?

Posted by Gordon McLeod (Member # 33) on 08-04-2003, 09:30 PM:

Deluxe edge waxes there prints

Posted by Richard Fowler (Member # 893) on 08-04-2003, 09:43 PM:

Competent service and projection on special venue is light years ahead of the typical cinema situation. Most of the loop cabinets we used ( Carter, after rebuilding the drive systems and Treiste ) had air squeegee and anti-static devices prior to running through the projection head. In our cabinets we where experiencing 9000 + passes with image fade the reason for replacement, with the then new VKF sprockets [Wink]

. The fact that our booths ran in laboratory type conditions also was a great help.
I have a friend who owns an advertising ad company who has 700 - 900 prints in rotation and is experiencing greatly less image
and especially sound track complaints ( and saving him replacement print costs ) since I introduced him to Film Guard.