Laser Discs: Measuring A "Lifetime"

It has been almost 2 decades since the first Laser Discs rolled off the production line in 1978. Back in those days, manufacturers were making incredible "last a lifetime" claims. At one show in 1981, I actually saw the salesman take a Brillo pad to a disc and then play it to prove just how indestructible the Laser Disc was. While the disc that received the Brillo treatment played fine, I asked him to play a copy of the now out-of-print CAV Discovision release of Coal Miner's Daughter that I had earlier seen running at the display. The resulting shower of colored sparkles that cascaded through most of the disc did not seem to bother the salesman. "It must be dust getting into the plastic molding equipment at the plant. I'm sure they will correct the problem" This is all the man could say about a problem that affected at least half of the demonstration discs at the display booth.

The Laser Disc Industry has learned much in the many years that have passed. Indeed, the only problem that has yet to be solved are salesmen (egged on by the people at the factory) giving glib responses when confronted with problems they would rather not deal with publicly. While answers and solutions to Laser Disc quality control and shelf life seem to be at hand, the manufacturers have been very reluctant to provide detailed information that may be useful to consumers. Even the caution that reads "Store in a cool, dry place" only shows up on some disc jackets, and does not explain the all important "why?". After months of research, and considerable resistance from the industry, we have assembled a number of facts about what affects the life all aluminum coated Laser Video and Compact discs:

Humidity

We put this one at the top of our list as the most problem causing environmental factor. High humidity forces moisture to actually travel into the plastic layer of the disc. This causes the plastic on each side of the laser disc to expand. If one side expands faster than the other, than severe but temporary warpage will occur. The problem subsides as soon as both disc sides acclimate to the environment's humidity level, but can return when there is a substantial humidity change. Combined with other adversities, humidity can also play a key roll in destroying the disc's vital aluminum reflective layer. By itself, however, moisture cannot damage the aluminum coating.

Heat

Under short term conditions, Laser Discs can withstand temperatures more than 135 degrees (fahrenheit). It is sustained low level heat found in summer or tropical climates that is the real danger. An increase in temperature effectively accelerates any chemical processes that may already present in the disc. Older discs with continimates in their adhisive coatings will "rot" much faster when exposed to both heat and humidity. Warm temperatures can also aggravate warpage problems, particularly when humidity changes are also present.

Reactive Chemicals

The key to premature aluminum coating failure is to combine both humidity and a reactive chemical. Sea salt, combined with the warm humid climate found at summer shoreline locations is one such example. Other sources of danger include oil furnace exhaust, swimming pool chemicals, or any household cleaners that contain chlorine or sulphur. Manufacturers must also make sure that reactive chemicals do not find their way into the disc during manufacturing. The majority of problems found in older discs are caused by chlorine in wash water or sulpher in adhisives. Purity in manufacturing adhesives and washing agents is essential for long disc life.

What You Can Do

Select a room for your discs that can be isolated from the outside environment, and make sure the air is kept dry. Air conditioning in the summer, along with heat in the winter, will usually keep the humidity down to an acceptable level. If you do not have central air, a small window unit can be purchased for under $350.00 from a discount appliance store. A dehumidifier may be a less expensive choice, but will tend to further heat up the room in summer. Given the proper care, the life of your discs should be measured in decades, and even poorly manufactured discs can survive for years.