Is our music safe on CD?

[Vanhalen 0]

Compact discs were sold as the durable alternative to vinyl - but anyone who opens the case of an ageing CD may be in for a nasty surprise.

Earlier this year, US web designer Dan Koster found 15% of his 2,000 CDs had begun to rot, and were unplayable and worthless as a result.

 

Holding his CDs up to the light, he said: "I was shocked to see a constellation of pinpricks, little points where the light was coming through the aluminium layer."

 

As we increasingly convert CD tracks for use on portable digital players and copy songs and photos onto CDs, there is renewed interest in the format's longevity. What causes CDs to deteriorate, and how wide is the problem?

 

Still vulnerable

 

Soon after compact discs came onto the market in 1983, owners realised that - while they were indeed more durable than vinyl or cassette tape - the CD was by no means indestructible.

 

Each CD comprises an aluminium layer which holds its data, sandwiched between polycarbonate and a protective lacquer.

 

The inlay booklet that came with your copy of the first big-selling CD, Dire Straits' Brothers in Arms, warned that the disc remained vulnerable to heat, cold, light, dust, fingerprints and scratches.

 

Stacking discs horizontally was bad for them, as was any Tomorrow's World stunt involving jam, drills or bulldozers. By obeying these rules, we were promised "a lifetime of listening pleasure".

 

That claim has since been questioned by CD owners including Jessica Ross, editor of Consumer Association magazine Computing Which?

 

"I have several that are unplayable a few months after buying them," she said. "To say they will last for 100 years simply isn't true."

 

Yet manufacturers maintain that bad handling is the main cause of problems with compact discs.

 

"Most people believe the underside of the CD is its most vulnerable part, when in fact it is the side with the label on," said Roy Varley, managing director of CD manufacturer Spool Multi Media.

 

"A slight scratch on the label side can damage the metal and cause the CD to skip or become unreadable."

 

Compact discs were made commercially available in 1983

 

However, this does not explain why careful CD owners have found discs in a worse condition than when they left them.

 

Eleven years ago thousands of compact discs in the UK became unplayable after they changed colour from silver to gold in a process known as "bronzing".

 

This was initially blamed on a reaction between the CD's lacquer and chemicals within the cardboard cases which housed them at the time.

 

But two months later, CD manufacturer PDO said all affected discs had been made in the late 1980s at its plant in Blackburn, Lancashire, which had used a silver coating on its discs instead of the standard gold.

 

Rusting effect

 

Spool Multi Media said while "most CD manufacturers aim for high standards", faults still occasionally develop.

 

"When the CD is made, protective lacquer is dropped onto each disc, which is spun to spread the lacquer to its outer edges," said Mr Varley.

 

"If this is not done properly, the lacquer may not cover the disc, enabling air to penetrate and oxidise the aluminium. Over time, this rusting effect can ruin the CD."

 

Record companies Warner Music, EMI, BMG, Sony and Universal declined to comment on the deterioration of compact discs.

 

Similarly, a spokesperson for CD manufacturer Sonopress would only say: "We tend to distance ourselves from being linked with CD deterioration."

 

But Philips, which co-developed the compact disc with Sony, said CD deterioration was an isolated problem.

 

"The reason for the huge success of the compact disc is its robustness, durability and quality," said communications manager Jeannet Harpe.

 

"Millions and millions of compact discs have been made and problems have only been found with an absolute minority of them. This can happen with any product."

 

Digital duplicates

 

Philips and Sony list the specifications of audio CDs in a manual known as The Red Book, which all compact disc manufacturers are required to adhere to.

 

"There is no problem with those specifications," said Ms Harpe. "If they are followed when a compact disc is made, it will last a lifetime."

 

No matter how remote the threat, the possibility of losing treasured albums, singles or digital photos will inspire many to duplicate their digital information onto a computer hard drive or recordable compact disc as a precaution.

 

"But recording your own CDs is not an exact science because home technology is not as sophisticated as professional CD manufacture," said Mr Varley.

 

"Computers can also develop faults - no format is completely 100% reliable. With that in mind, the compact disc is still the best format there is."