CBC Digital Archives

Preservation & Restoration

Videotape lasts longest when it's stored in cool, dry conditions. But even then, it doesn't keep forever. The most common aging problems are dirt build-up and decayed tape oxide that falls off the tape backing. When this occurs, the heads on the player have trouble reading the signal and they will get clogged up. Every tape is run through a cleaning machine before you're able to make a quality copy.

In the normal cleaning cycle, the tape is first wiped free of dirt with a couple of small tissues. Next, it is rubbed up against a small blade that removes any loose magnetic oxide particles. The final step sees the tape passing over a third tissue on the take-up reel. Then the whole process is reversed. None of this should affect the TV show on the tape.

Even tapes in pristine condition may still have video "noise" and other imperfections that reflect their age and the type of equipment from which they were produced. If so, a technician uses a "video noise reducer" that removes imperfections before copying. Colour loss and other imperfections can often be corrected at this time, too.

For tapes with serious oxide decay - it can be literally peeling off - there is another option: the ovens! No, not to burn them, but to warm them. Over the years, people working with old tape have learned that gentle heating - for anywhere from six to 24 or more hours, at temperatures ranging from 35°-65° Celsius - can actually cause the magnetic oxide to re-bond with the tape backing. The tape can then be run through a player and copied - but usually only once. The shock from the heating and re-bonding often renders a tape more fragile, so that it falls apart completely after that one last play. Such an all-or-nothing strategy is only tried when nothing else will work.

Compared to magnetic audio or video tape, 16mm film is quite durable. As a result, most of the work done in the CBC Archives with old film has had to do with preservation and copying, rather than restoration.

In terms of storage, the biggest effort has been devoted to re-canning. That meant taking tens of thousands of film reels out of metal cans and placing them into ventilated plastic "cans." Slightly more care and attention was required for the several thousand reels afflicted with vinegar syndrome.

Beyond that, transferring film to digital Betacam format -- usually done when someone needs a copy for fresh use or re-sale - is a straightforward process. First, a technician reviews the films using an editing machine (typically on something called a Steenbeck). The technician then combines small reels onto larger ones and makes minor repairs to damaged splices and damaged sprocket holes. The technician also makes sure all picture and sound elements are synchronized.

The next step is washing. For this, the film is loaded into a machine with a cleaning tank at the bottom, filled with fast-drying, environmentally friendly liquid. The film passes through the liquid, over buffer rollers and Particle Transfer Rollers that help remove dirt and then through a "sonic shaker" that frees up more particles. The PTR rollers work like little "lint brushes" to remove dirt from the film.

Once film is clean, it is turned over to a technician in one of two "video transfer suites" or "scanner rooms." The equipment in here is part of a sophisticated, computer controlled system that permits the operator to do quick colour and contrast corrections before copying. Sometime the before-and-after results are spectacular. At least two digital Beta copies or a BetacamSX are made of any film that passes through the transfer suite, sometimes more (either Beta or VHS).

The Radio Archives began taking shape as early as the late 1950s and early '60s. The first serious preservation and copying work began in the late 1970s, when technicians in the department began copying audio from old acetate discs to tape.

Acetate discs are durable and once they are vacuum-cleaned to remove dust and dirt, they are relatively easy to copy. The trickiest part is making sure you have a turntable that can play them. (Do you have a 78-rpm record player lying around at home?) Those used by the CBC have two pick-up arms - one for playing back discs that are engraved from the inside out, and the other for playing commercial outside-in recordings.

The principles behind cleaning magnetic audio tape is much the same as video tape, but the process is different.

To clean 1/4-inch audio tapes, the tapes are mounted to a tape player and then run through the machine at high-speed. If the tape is dirty, a sticky film will collect on the rollers that are used to set and balance tension. The operator then takes a cotton swab and some rubbing alcohol and wipes the rollers clean.

As with video tapes, those audio tapes with serious problems magnetic oxide decay can successfully be "baked" in the ovens before copying.

Cleaning up sound is different process. For cleaning up hisses, scratches, pops and other sound impurities, the archives rely chiefly on several technology systems, including Pro Tools.