inSync reader Rod C. recently inquired about using CD recordable media in CD players. "Occasionally, I run across a CD deck (almost always "consumer" type) that will play part of a song then skip uncontrollably. Someone told me that those disks actually use an optical process to be recorded, and if it sees too much sunlight, it will deteriorate so that some players will not play them. Is that hogwash?"

There are many reasons why a CD might not play in a player. Sometimes if the CD has mild scratches or scuffs it can misplay in one player while working fine in ten others. If a CD player's laser is slightly mis-aligned it may have trouble with discs that aren't quite perfect for one reason or another.

There are several studies under way testing the long term viability of various optical media technologies. The general understanding of the write once CD's is that they are not absolutely permanent. Some degradation does occur over time. I am not sure what effect sunlight would have on the degradation, but I speculate that it could cause discoloration of the plastic coating which would ultimately compromise the performance of the disc. The recordable CD's do use a laser to be recorded, but given that it heats the inside of the CD to around 2000 degrees during the recording it is unlikely that normal sunlight would effect it very much in that way.

The other possible problem is that consumer machines use all different types of error protection schemes. In rare cases some of these schemes may not be compatible with a particular type of recording scheme one of the write once CD recorders uses. More specifically, they may not be able to completely correct certain types of errors that recordable CD's have. I have personally observed this problem at home with my Yamaha CDR100 recorder and an old Sony hi-fi CD player. All CD's have errors, but sometimes the types and quantities of errors produced by recordable CD's are harder for some machines to deal with.