CD / DVD Care & Preservation

Breaking the Myth: CDs Can be Damaged and Can Deteriorate

CDs and DVDs have been widely marketed as nearly indestructible, but that’s a myth. CDs/DVDs are more vunerable than you might think. To understand how they can be damaged, it is first necessary to know how CDs and DVDs are constructed and how they are read by the CD/DVD player.

How CDs/DVDs are Constructed

The production of a CD or DVD begins with the creation of a 1-mm thick polycarbonate disk that has the data pattern impressed on one side as tiny pits. The data side of the disk is then coated with a reflective aluminum film that isonly a few atoms thick. Next, a very thin acrylic overcoat (1/3 the diameter of a human hair) is applied over the aluminized layer and is allowed to dry. Finally, the inks with the label information are applied on top of the acrylic layer.

How a CD/DVD is Read

CD readers rely on light reflected from the aluminized layer to obtain the digital signal from the CD. The CD is ingeniously designed so that the laser light reflected from the pits is exactly out of phase from the light reflected from the nonpitted areas of the disc. This appears to the CD reader as a flickering light that is read as a series of ones and zeros. In turn, this digital signal is 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 or DVD player reads the digital information from the shiny side of the CD/DVD, it must see every microscopic “pit” of the digital code. Any dirt, fingerprints, or scratches that come between the laser and the information prevent the correct reading of the musical or video information. 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 most importantly, it polishes the surface of the disc, improving the optical quality and allowing for more accurate reading of the data. The same polishing action makes it much 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 in such way that you may hear distortion or see a degradation of the video image.

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.

DVDs that have read surfaces on both sides are highly unlikely to have this problem, because the aluminized layer is well protected by being sandwiched between two thick polycabonate layers.

Preventing Damage to the Aluminized Layer: You can apply Digi-LAST Protective Shields to the label side of your CDs or DVDs to seal them from oxygen and the damage it causes.

DIGI-Last shields are made from a unique film that adheres to the CD/DVD label side without glues or adhesives and never becomes sticky or gummy.