TECHNOLOGY TO WATCH SHELF LIVES AND VIDEOTAPE Now they tell us: Memories recorded on VHS tape may not last for more than a decade.
By ROBERT ZIMMERMAN This article is adapted from the September/October edition of The Sciences (800-843-6927) and appears with permission.

(FORTUNE Magazine) – Since the 1970s the videotape and electronics industry has been trying to persuade Americans to throw out their movie cameras and buy VHS camcorders to preserve family histories. Videotape is cheap, relatively easy to edit, no problem to set up and watch. Then, consumers have been told, they can share with their descendants priceless documentary footage of births, bar mitzvahs, marriages, and other memories, say, 30 or 40 years down the road. If you're taking that advice, maybe you'd better keep a diary. Few people outside the industry know that the life expectancy of half-inch VHS videotapes is much shorter than originally predicted -- perhaps as short as ten years. | Recent technical reports by the Sony, Ampex, and Agfa corporations and the Institute of Electrical and Electronics Engineers suggest that unless magnetic tapes like VHS are carefully stored and maintained, their lives can be fleeting. The problem, it seems, is bad chemistry. Videotape is made from a base of polyester, which is coated with polyurethane. The coating acts as a binder, trapping magnetic oxide particles -- the carriers of the magnetically encoded information -- within the tape. That binding system is fragile: High temperatures and humidity can play havoc with it, causing the urethane particles in the coating to react with water, break free, and migrate to the surface of the tape. The next time the tape is played, the oxide particles, no longer encumbered by their binder, peel off, taking with them all evidence of baby's first steps, Tad's graduation, or that zany trip to Cancun.

But all is not lost: Sony, Ampex, and other manufacturers have put out a list of recommendations -- some verging on the draconian -- for extending the life of videotapes: -- Store the tapes at a temperature between 59 degrees and 77 degrees Farenheit and a relative humidity between 40% and 60%. -- Fast-forward and rewind your tapes at least once every three years. That should keep the polyurethane binder from sticking to adjacent layers of a tightly wound tape. Adhesion will either prevent the tape from running or, if the tape does run, will tear the oxide particles from the base, thereby destroying the tape and gumming up the recording machine. -- Before storing your videotapes, rewind them from end to end in one complete, uninterrupted procedure, preferably with a separate rewind machine that applies a constant tension to the tape. -- Buy only the highest-quality tape. It is coated more evenly and therefore lasts longer. You can spot high-quality tape the way you spot high-grade gasoline: Tapemakers call top-of-the-line offerings ''gold'' or ''premium'' and charge extra for them. There is more. Seal the tapes in plastic bags, to protect them from dust, smoke, and moisture; store them vertically, with the tape wound entirely onto the bottom spool; don't play them right away if they've been out in the heat or the cold; keep them away from strong electromagnetic fields -- such as the ones created by stereo speakers and television sets. It's enough to send a video jock off to the flea markets for an old Super 8.