(Eerie organ music is heard, fog rolls in and covers the half obscured tombstones. Strange shapes move about in the pale moonlight. A figure, dressed in black, walks toward you. He steps into the flickering candle light and begins to speak. A wolf howls in the distance)
Well, your worst fears are realized: A whole Audio Society column about laser rot. Yes, put the children to bed, lock up small pets and gather the loved ones close, for this column will not be pretty.
"But what's this?", you say, "I thought Compact Discs were supposed to last forever." So did I, dear reader, so did I. I can even remember reading all of Philips' advance documentation and promises about near infinite life spans. Well, you and I and the engineers at Philips forgot one thing: Aluminum is a very reactive substance. (How many 75 year old aluminum mirrors do you have around the house, anyway?). That's the problem in a nutshell - aluminum really wants to become aluminum oxide. If you go back and play my videodiscs from 1984 and earlier, you will find that they are slowly turning to colored snow. Some are worse than others, yet all are showing some signs of oxidation, or as one wag put it, laser rot. Now Pioneer says that they have the situation under control, and all laser discs from 1985 onwards are free from oxidation problems. But as recently as February 1990 the problem popped up again as 3M announced that all discs manufactured prior to February 1990, may have a problem with aluminum oxidation if kept in a warm, moist environment (such as your shower - never keep your discs there.) The third, major laserdisc manufacturer, Technidisc ran into this problem in 1989, and only guarantees that their discs manufactured from 1990 onward are free from laser rot. And there is no proof that any of these companies have really solved the problem. Only time will tell.
"Okay", I hear you saying, "but I don't have Laser Discs, I have CD's." Fair enough, except that the same technology used to make Laser videodiscs are used to make CDs. Plus, CDs are missing one side. Laser Videodiscs are two sided, with an insulating layer of latex between the aluminum layers. CDs are one sided, with a thin lacquer coating over the aluminum, upon which is printed a label. If the inks in this label aren't made according to Philips specifications, they will "corrupt" the aluminum layer, making the disc unplayable. Sound implausible? Well, I thought so too, until this very problem happened to me. The disc in question: "Technique" by the pop group New Order. This CD, pressed by Discovery Systems, for Qwest/Warner Brothers, has a custom label. Visibly there appears to be nothing wrong with the CD. In fact, for about a year I enjoyed trouble free, crystal clear sound. Until one day, I pulled the CD out of its jewel box, placed it into my CD player, pushed the play key, and heard tremendous bursts of snow, pulsating in time to the drum beats. I thought I might have some dust on the CD so I pulled it out of the drawer. Nope, it was clean. Put it back in the player and pressed play again. Nope, still heard snow. Tried it in different players. Same thing. Then a friend suggested I check some of my CDVs, (Compact Disc Videos) since they were being recalled in Europe. Sure enough, most of the gold colored CDVs pressed by Philips in Europe (including major American CDV releases by Madonna and the Cure) had colored flecks in the picture that weren't there before. Then my brother tried his Dire Straits CDVs (also pressed by Philips in Europe). They were far worse. The "Money For Nothing" CDV actually had visible signs of oxidation. In fact, the label side of this disc actually came off on his fingers when he touched it.
So to put this in perspective, of my 470 CDs, about 14 are showing signs of oxidation, 13 of which are CDVs. The CDVs are still playable. The CD is not. About 10 Videodiscs (out of 213) have deteriorated quite noticeably. Unfortunately for me, the videodiscs are primarily Japanese imports, which are probably irreplaceable. Why the discrepancy between the video mediums (CDV and Laser Disc) and the audio only compact disc? Glad you asked that. You see, the video on CDVs and Laser Discs is an analog signal. Any imperfections present on the discs shows up as video noise (in this case, colored "flecks") and is therefore readily noticeable by the eyes. However, CDs are a digital medium, and as the surface deteriorates, and errors happen more and more often, the error correction circuitry just interpolates the missing data, and keeps going. No audible deterioration is noticed until the surface of the disc gets so corrupted that the missing data cannot be interpolated. Then, the error correction circuits will basically "give up" and either mute the outputs of the player, or let it play what the laser is reading, regardless of the consequences. So, as far as you're concerned, your CD will sound flawless right up until the point where it dies forever, with no advance warning, no way to make a back up copy. Your favorite CD, the one you bought on that hot, muggy day in Australia, could be deteriorating minute by minute, waiting to surprise you that fateful day when you put the disc into your player and all that comes out is digital snow, or maybe not. That's the real kicker. There is no way of knowing which discs will rot, and which discs won't. I have some Dire Straits CDVs as well, and they're in much better shape than my brother's. Also, I have some 1981 Japanese Videodiscs, and they're fine.
So what can I tell you? If you ask Pioneer, 3M, Technidisc or Philips, they will tell you that they had problems with oxidation in warm, moist climates, but that's a thing of the past, and the new accelerated aging tests prove that they have solved the problem. But they originally ran accelerated aging tests to prove the validity of the medium, and this still happened. No, I'm afraid that we are the world's most expensive optical medium life expectancy laboratory, and it will be up to us to keep accurate track of our laser based mediums. Maybe we gave up on the record a little too easily. For all their faults, vinyl records are still around from the 20's and 30's, and with proper care, will still be around.
Note: From all the evidence that I have seen, the 24 Karat Gold Ultradisc, by Mobile Fidelity Sound Labs may be the only solution. Theoretically, (and I'm not a metallurgist, so don't quote me) only Gold would seem to have the neutral properties required of long term storage. However, the price of 24 Karat gold coatings would make the CD a rather expensive item, defeating the very reason Philips went to aluminum in the first place. And there's still no guarantee that the gold may not evaporate off the CD surface, like some the aluminum based CDs have done.
Unfortunately, we don't have time to talk about why all the Ampex studio recording tape manufactured from 1970 to 1980 is slowly fusing together and all the major studios are trying to salvage what albums they can. Or why DAT headwear is turning out to be a real problem and how your DAT tapes could, theoretically, be unplayable within a few years. But, those stories will wait until next time. So... friends.... Until next month.... Pleasant.... Dreams.... (Sound of creaking door is heard, and maniacal laughter.)
Last Updated: April 12, 1996