The American Society of Cinematographers

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Return to Table of Contents September 2007 Return to Table of Contents
The Bourne Ultimatum
DVD Playback
Points East
Post Focus
Chace Audio
Saving Sound Tracks

Cinematographers are understandably interested in image permanence and motion-picture restoration, but ever since Al Jolson uttered the words “You ain’t heard nothin’ yet!” in The Jazz Singer 80 years ago, it has been a fact of movie life that sound goes hand in hand with picture. It is equally true that if a talkie lacks its sound track, there’s a fair chance the image will be left to rot as well. Although the artist may rebel at the notion, from a commercial perspective what’s the point of spending money to preserve the image if the dialogue, music and effects can no longer be heard?

In many ways, sound elements are even more fragile than picture elements. For most of the last 50 years, movie sound was mixed and mastered on acetate-based, oxide-coated magnetic film stock, which is subject to the same sorts of degradation that can occur with acetate-based images: it can shrink, warp and become brittle. The adhesives that hold the magnetic coating can dry out, and the “rust” that carries the precious sound modulations can flake off and clog delicate sound heads, making it difficult to create a new sound transfer.

“Vinegar Syndrome is the layman’s term for a complex chemical reaction that occurs in acetate-based film stocks and causes them to decompose,” says Thom Piper, manager of preservation and senior optical recordist at Chace Audio in Burbank. “As acetate film breaks down, it releases water and acetic acid, which causes the vinegar smell. This decomposition affects both picture and magnetic sound acetate-based films, but not equally — the catalyzing effect of the iron oxide in the magnetic coating of sound film can intensify the problem significantly. A 1,000-foot reel of 35mm acetate film can generate over a quart of ‘vinegar,’ and sound elements from as recently as 30 years ago are generating gallons of the stuff. As magnetic film decomposes, the plasticizers appear on the magnetic surface as a thick, white powder. During a transfer, this powder builds up on the sound head, causing loss of contact and dull, muffled transfers.

“When a film comes into Chace for sound preservation and restoration,” he continues, “it’s logged into our vault and tracking system and then sent to our film-preparation department, where it is cleaned and repaired if necessary. We have proprietary procedures that can get rid of mold and water damage, reduce vinegar syndrome, and solve other problems. Film preparation is really the key to starting the preservation and restoration process. In extreme cases, with a track that exhibits strong indications of vinegar syndrome, once the film has been cleaned, repaired and exposed to air there’s only a short window of time in which to make a transfer. Decomposition takes place over time, but once it reaches a tipping point the process can accelerate significantly. Once the film has been cleaned, we’ll immediately have a copy made and bag the original to limit its exposure to the air.”

Sound elements are also subject to the effects of mold and mildew, which can also make them unplayable. As part of the preparation for vinegary and moldy prints, Chace has developed a “magic box” they call the “Stinkerator.”  Michele Winn, manager of Chace’s film-preparation department, explains, “The Stinkerator cabinet uses negative ions and UV-light technology to inhibit and neutralize the growth of mold and mildew. It also safely reduces the vinegar smell from elements prior to handling. Inhaling the vinegar fumes may have negative health consequences for the technicians handling the film, and we need to neutralize the acetic-acid smell as much as possible so they can safely do their work. Other safety precautions include air filtration and purification, eye goggles and breathing equipment. We also use our Multi-function Magnetic Film Cleaning Machine, which automates several processes needed to prepare magnetic-sound film for transfer. The unit can remove excessive dust and plasticizer in one pass, replacing what might otherwise take 40 hours of hand-cleaning.”

But what to do if a soundtrack is essentially beyond recovery?

Chace Audio was recently contracted by 20th Century Fox to restore the sound for The Diary of Anne Frank (1959), which won William C. Mellor, ASC an Oscar for black-and-white cinematography and notched an Oscar nomination for composer Alfred Newman. “The 35mm four-track stereo magnetic sound master had sections with advanced stages of vinegar syndrome,” says Piper, “and the problem was so severe that in some areas the magnetic oxide was separating from the acetate base. Even the small amount of friction created by running this over a magnetic sound head caused an unsatisfactory ‘chatter’ or ‘screeching’ quality.”

The track elements were effectively unusable, and there was a very real prospect that the soundtrack would only survive in monaural sound rather than the stereo format originally heard in theaters by road-show audiences. But Piper has developed a proprietary lubricant for use on deteriorated soundtracks that Chace Audio has dubbed “ThomSlick” in his honor. “It took me about a year, on and off, to come up with the formula,” says Piper, who declines to be specific about ingredients but says they contain no carcinogens. “Others have used WD-40 to lubricate mag film, but we’ve found petroleum-based products rapidly accelerated the decomposition of the film. What we came up with doesn’t do that; it works as a lubricant, we didn’t get any buildup on the sound heads, and it didn’t affect the high-frequency response of the recordings. It doesn’t work for everything, but for mag films that are decomposing and generating a lot of head buildup, it works great.

“ThomSlick is sort of like The Blob: it doesn’t like being contained, but once it’s on the film it stays there,” he continues. “The longer it stays on the film the better the film starts to look, because it causes the film to relax so it lies flat and runs more smoothly.”

With a laugh, he adds, “When I first came up with the formula, I spilled some on the rubber floor mats in my truck, and when I got in the truck, I literally slid out as soon as my feet hit the stuff! I had to throw the mats out, but the stuff works wonders on deteriorating acetate film.”

The application of ThomSlick revitalized Anne Frank’s aging stereo masters and allowed them to be transferred without screech or chatter, preserving the audio in the configuration the filmmakers intended.

Chace Audio, (818) 842-8346,

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