Some CDs once thought to be indestructible are now rotting

May 27, 2004

A while back, we reported about the issue the risk of 'DVD Rot' and why it is recommended to make a backup of original discs. Now there is news about the 'CD Rot' issues of music CDs; particularly those manufactured up until the late 80's. When Tomorrow's world first demonstrated how 'robust' CDs are and how the contents are unaffected by surface contaminants and jam, it was reported that CDs were pretty much indestructible. Now music lovers are finding many of their early CDs have started having playback issues or are totally unplayable despite even proper handling.

If the lacquer (coating) is incorrectly applied to the CD during its manufacturing stage or is of the wrong type, it can react with the ink from the printed inlet/booklet or allow the aluminium reflective layer to be exposed to the air and oxidise (also known as CD Bronzing). In either case, it will make the affected section of the disc or entire disc unplayable. CD Rot is visible as either red spots or scratches near the disc edge or pin holes in or perforating of the aluminium layer when held up to the light.

In laboratory testing, CDs have been found more likely subject to 'CD Rot' if mishandled or subject to damage or scratches on the label side. CDs should be handled as delicately as records, kept clean and placed in a jewel case when not in use. Most CDs from the 90's onwards are estimated to last 50 or more years if handled properly.

WHEN they first appeared in the late 1980s, CDs were hailed as an almost indestructible form of storing music.

But to the dismay of rock fans, recordings by artists such as Bruce Springsteen, David Bowie and Pink Floyd have begun to suffer from CD rot.

Music fans may not notice at first when little red spots and scratches start appearing at the edge of the shiny discs.

But when they try to listen to their favourite album they will find the CD skips, jumps or is completely unplayable.

"I don't understand how plastic and metal can rot," said Sarah Hopkin of Edinburgh, who said she was disappointed to hear that her extensive CD collection may not last forever.

"I remember when CDs first came out, Tomorrow's World said they were indestructible and you could cover them in jam. Now it seems that's not true.

Read the full article here.

This gives another reason why it is recommended to make a backup of precious or limited edition CDs, even if subject to proper handling. So far, I have only seen rotting of CD recordable, especially those early 'low cost' CD-R's. However in this case, I have seen the coating deteriorate in a matter of weeks if it does happen, for example one Memorex CD-R I kept in a CD wallet for about a month had a 5mm circle of corrosion on the label side making part of the disc unreadable.

I would recommend checking the edges and surface of all CDs (especially pre 90's and CD-R's) for any sort of deterioration or pinholes once every few months and make backups if necessary.

Feel free to discuss about CD and other optical disc issues on our Media Forum.

Source: NEWS.scotsman.com