CD / DVD Care & Preservation

Breaking the Myth: CD/DVD Damage and Deterioration

Clever marketing describes CDs and DVDs as nearly indestructible, but that’s a myth. CDs/DVDs are more vulnerable than you might think. To understand disc damage, it helps to understand CD and DVD construction and how the CD/DVD player reads them.

CD/DVD Construction

The production of a CD or DVD begins with a 1-mm thick polycarbonate disc that has the data pattern impressed on one side as tiny pits. The disc’s data side is then coated with a reflective aluminum film that is only a few atoms thick. Next, a very thin acrylic layer (1/3 the diameter of a human hair) coats the aluminized layer and dries. Finally, inks with the label information cover the acrylic layer.

Reading a CD/DVD

CD/DVD readers rely on laser light reflected from the aluminized layer to obtain the digital signal. The disc is ingeniously designed so the light reflected from the pits has opposite phase from the non-pitted light reflection. This appears to the reader as a flickering light that is read as a series of ones and zeros. In turn, this digital signal gets decoded into music and video.

CD/DVD Damage Can Occur in Two Ways

1) Damage on the Read Side

When the laser in your CD/DVD player reads the digital information from the shiny side of the CD/DVD, it must see every microscopic “pit” of the digital code. Dirt, fingerprints, or scratches that come between the laser and the information prevent the correct reading of the musical or video information. The disc contains redundant information it uses correcting errors, but sooner or later a build up of dirt and/or scratches will take away from the musical or video experience. A large scratch may cause “skipping” or prevent playback entirely.

Buff with cloth, moving straigh outward to the edges, not in a circle

Preventing and Repairing Damage to the Read Side: The LAST CD/DVD Cleaner and Treatment is an exclusive formula that cleans dirt and fingerprints, repairs minor scratches, and polishes the surface of the disc, improving the optical quality and allowing for more accurate reading of the data. The LAST CD/DVD Cleaner and Treatment also makes it more difficult for dirt and fingerprints to stick to the surface.

2) Damage to the Aluminized Layer (the label side)

Any oxygen that penetrates to the aluminized layer can permanently damage your CD/DVDs. When oxygen combines with the aluminized layer, it forms aluminum oxide that is transparent and CANNOT reflect the laser beam. The lack of a reflected signal confuses the CD/DVD processor such that you may hear distortion or see degraded video.

The acrylic layer (on the label side) is very thin and any pinholes formed during manufacturing or any scratches in the acrylic can expose the aluminized layer to the damaging effects of oxygen.

Double-sided DVDs are unlikely to have this problem because the thick polycarbonate sandwich protects the aluminized layer.