Those of us who have recorded video and audio on magnetic tape have by now learned an essential truth: magnetic media does not last forever.
Like all known storage media, tape is not permanent. Sadly, no one knows exactly how long the recorded content will play on old tapes. This is all trial-and-error stuff.
After Orson Welles died in 1985, I was offered a collection of his old tape and disc recordings of the Mercury Theatre radio shows from the 1930s through the 50s to edit and enhance for a retrospective called “Theatre of the Imagination.” I did the project, but had no idea what I was getting into.
Not only did the project involve gluing together old glass discs of recordings, but I had to bake reels of audio tape in a kitchen oven and then try to get them onto digital media in a single playback. It was quite a tricky business. (Then came the computer process to remove clicks, pops and tape noise.)
Though magnetic wire recording has been around since its invention by Danish engineer Valdemar Poulsen in 1898, it would be 1934 before the German division of General Electric invented the Magnetophone, a device that recorded audio on plastic tape coated with magnetic particles.
In May, 1946, Jack Mullin — introduced to the recorder in England as a soldier in World War II — started improving the Magnetophone and introduced the first demonstration of audio recording in the United States.
Singer Bing Crosby, who hated doing live radio shows for different time zones, invested in the technology and, in 1947, Crosby became the first performer to record a radio program on audio tape. The recording technology Crosby was built by Ampex.
At NAB in 1956, Ampex introduced the Mark IV, the first video recorder using huge reels of two-inch wide magnetic tape. While audio recording was accomplished by pulling the tape past a stationary recording head, video was recorded by spinning the recording heads. An engineer got the idea from watching moving vacuum cleaner brushes.
Now that we have had more than 75 years of experience with traditional cobalt ferric oxide tape and more than 35 years with metal tape formulations, what do we know about the longevity of recordings on tape
According to research done by Sony in 1991, both oxide and metal tape, when stored under normal room environmental conditions of 77 degrees F and at 50 percent relative humidity, “are very stable and have no change in video electromagnetic performance.”
If stored “consistently” under these conditions, Sony predicted both tape formulations would last 15 years without significant degradation. That means today — since 15 years has long passed — most of those tapes are questionable as to playback reliability.
The life of all magnetic tape depends on the decomposition of its chemical components, Sony said, such as plastic base film, binder polymers, back-coating materials, lubricants and dispersing agents. Heat and moisture attack these organic materials in both co-oxide and metal formulations.
Outside of dubbing them to digital formats, here are some tips for protecting magnetic tape:
- Store magnetic tape with a constant temperature and humidity in a dust-free environment. It is best between 59 and 77degrees F with 40 to 60 percent relative humidity. This helps prevent expansion and contraction of the base film of the tape.
- Wind the tape properly. Unevenly wound tape will stretch over time, causing problems in playback.
- Store tapes upright. Do not stack them flat on shelves. Excessive weight can damage tapes.
- Every three years, fast forward and rewind tapes.
- Don’t leave tapes near speakers, motors, high voltage transformer or other devices which generate a strong magnetic field.
- Keep your old video recorders properly maintained. Since video tape uses a thin plastic base film, irreparable wrinkles and scratches can happen when played on a VTR with a faulty tape transport mechanism or tape path.
Of course, let’s be realistic. These recommendations are very tough and hard for most of us to acheive. Orson Welles’s tapes were stored in a cardboard box in a garage for more than 30 years!
For most of us, video tape is comfortable in the same kind of environment that makes people comfortable. Just don’t let tapes get too hot or cold.
Finally, and perhaps most important of all, if your tapes contain valuable or one-of-a-kind content, make new copies to digital media as soon as possible and do this every few years. It is a good rule to backup old video programming every five years to the latest, most reliable archival medium.
Remember, no video or audio tape is forever. So don’t take backups for granted.