President's Message
January 2009

1.  Saving Film Soundtracks by Robert S. Birchard

In many ways, the sound elements of pictures are even more fragile than the picture elements. For the last 50 years movie sound was mixed and mastered on acetate-based, magnetic oxide coated film stock [before that it was optical]. "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. The catalyzing effect of the iron oxide can intensify the problem significantly. As it deteriorates, plasticizers appear on the surface of the film as a thick white powder, causing loss of contact and dull, muffled transfers.

They've developed a machine which automates several cleaning processes and replacing what otherwise would take 40 hours of hand cleaning.

Chace was recntly contacted by 20th Century Fox to restore the sound for The Diary of Anne Frank (1959). The 35mm four-track stereo magnetic sound master had sections with advanced stages of vineger syndrome. The deterioration was so severe that the oxide was separating from the acetate base. Even the small amount of friction created by running this over a magnetic sound head can cause an unsatisfactory "chatter" or "screeching." There was a strong prospect that the soundtrack would only survive in monaural sound. Thom developed a proprietary lubricant Chace dubbed "ThomSlick." "It took me about a year, on and off, to develop the formula." says Piper, who declines to be specific about the ingredients,but says they contain no carcinogens. "Others have used WD-40 to lubricate mag film, but we've found that petroleum-based products rapidly accelerated the decomposition of the film. What we came up with doesn't do that. 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." The application of ThomSlick allowed the masters to be transferred without screech or chatter, preserving the audio in the configuration the filmmakers intended. [I wonder if it would work on audio tapes that have dried out?-- DBH] American Cinemaphotographer SE 2007.

2.  Movie pirates are going after Blu-ray, using a technological twist that makes their illicit copies both cheap to make and tough for consumers to spot. Pirates are taking advantage of the fact that many viewers can't tell the difference between Hollywood's new high-definition higher priced Blu-ray movie format and a bootleg format--called AVCHD--tha's a gradelower: AVCHD uses 720 horizontal lines of resolution instead of Blu-ray's 1080, but still offers a sharper picture than an ordinary DVD on high-definition television sets. The movies are pulled off Blu-ray discs using easily available software. Because of the lower resolution, they can be put on ordinary blank DVDs instead of more costly blank Blu-ray discs. That makes them quite profitable for pirates to make. WSJ 12Nv08

President, Boston Audio Society

email me HERE


The Boston Audio Society
PO BOX 260211
Boston MA 02126

problems? email Barry:

updated 2/7/09