Better yet, let us transfer your LP albums and 45 records for you onto quality CDs so that you can enjoy them without adding wear each time you listen.

• before storing, when surface contamination is visible
• before recording, when surface contamination is visible
• before playing, to prevent surface contamination from being “flung off” while the disc is spinning in the disc drive
• when readability (playability) is impaired and surface contamina-tion is visible

In general, avoid using organic solvents. Harsher solvents (ac-etone, benzene) will dissolve the polycarbonate and damage the disc beyond repair. Mild solvents (isopropyl alcohol, methanol), however, may be used. These mild solvents evaporate quickly and will not disthe polycarbonate.

Other solutions that are not harmful are water-based lens clean-ers or water-based detergents (with mild soap) formulated for clean-ing CDs or DVDs.

The polycarbonate substrate is a relatively soft and transparent type of plastic. Each time a disc is wiped, rubbed, treated with some solution, or otherwise manipulated for cleaning, that substrate, and thus the disc itself, is at risk of scratching or contamination.

If the disc needs cleaning, remember these tips:

• Use an air puffer to blow off dust.
• Use a soft cotton cloth or chamois to wipe the disc.
• Try cleaning with a dry cloth first, before using any cleaning solutions.
• Do not wipe in a direction going around the disc.
• Wipe from the center of the disc straight toward the outer edge.
• Avoid using paper products, including lens paper, to wipe the disc.
• Avoid using anything abrasive on the surface of the disc.
• If the disc has a heavy accumulation of dirt, try rinsing it with wa-ter first.
• Use commercially available water-based detergent formulated for cleaning the surface of optical discs.
• Use isopropyl alcohol or methanol, as an alternate to water-based detergents, to clean the disc surface.

The inks in markers vary in chemical composition and are formed from pigments or dyes, and solvents. Inks are divided into three basic categories according to the type of solvent used: water-based, alcohol-based, and aromatic solvent-based. Within these cat-egories, inks are further divided according to their permanence and their application to different surfaces.

Markers themselves also vary in form: there are fine-point, extra fi ne-point, rolling-ball, ballpoint, soft felt-tip, and chisel-tip. Some are ideal for CD labeling; others can cause damage. Numerous CD vendors have noted that the thin protective lacquer coating can deteriorate from contact with certain solvents in markers. To eliminate the risk, water-based markers are recom-mended for CD labeling. As a solvent, alcohol is generally less damaging than xylene and toluene, which are common in aromatic solvent-based markers. According to anecdotal reports, alcohol-based markers can be used to label CDs without causing perfor-mance problems. However, there are no explicit lab test results to show what effect solvents in markers have on different CDs or DVDs, particularly over the long term. The vulnerability of the metal in CDs, because of its proximity to the surface, should be considered when choosing a marker. The metal is particularly susceptible to damage from scratches, scrapes, or denting caused by surface marking. A felt tip marker will mini-mize the risk of scratching or denting. As mentioned before, CDs and DVDs look similar, but their layer structures differ. The recording layer of a CD is located just beneath the labeling side. On a DVD, the recording layer is in the center of the disc. In theory, solvents from a solvent-based marker will not penetrate to the center of a DVD through the polycarbon-ate layer on both sides of the disc. Consequently, the data and met-al layers in the center, in theory, should not come in contact with any harmful solvents. Nevertheless, the same precautions taken in labeling CDs are advisable for DVDs. The marker used to label a CD will work just as well on a DVD. Restricting oneself to the CD-safe marker will also eliminate the potential for mix-ups in the use of distinctive CD or DVD markers.

Many vendors sell CD-safe markers, and they vary in ink so-lution. They should not contain any solvents harmful to CDs or DVDs but should have a permanent quality. For risk-free labeling of any disc, it is best to mark the clear inner hub or the so-called mirror band of the disc, where there are no data.

Scratches on the Laser-Reading Side of CDs and DVDs

Even assuming a scratch is deep or wide enough to influence laser focus, error detection and correction coding in the disc drive can in many cases recover the misread data. However, scratches that are deep, wide, or bunched together can adversely affect the readability of the disc. These scratches can cause the laser to misread enough data to make error correction coding ineffectual.

While data errors generated from scratches that run outward from the center of the disc stand a good chance of correction by the error correction firmware, scratches running in the direction of the track, the same direction as the laser reads the disc, are more likely to cause uncorrectable errors. If scratches are deep enough to damage the data or metal layers on the reading side of a disc, the data cannot be read or repaired.

Scratches on the Label Side of CDs
Scratches on the label side of discs can be a more serious problem. Because the reflective metal layer and data layer are so close to the surface of the label side of the disc, they can be damaged very easily. A slight indentation, or pinhole in the metal from a scratch, pen, pencil, ultrafine marker, or other sharp object will destroy the reflectivity of the metal in that area on the other side (laser reading side) and the readability of the data by the laser. This type of damage cannot be repaired.

As with scratches on the laser-reading side, optical disc drives are usually able to read through minor damage easily, even if the damage is caused from the label side. The difference is that this damage is permanent. If the error detection and correction firmware in the disc drive cannot correct the data, it will not be recoverable. Scratches that do not reach through the thin protective lacquer coating should have no immediate effect but may ultimately expose the metal to moisture, air pollutants, or other adverse environmental influences.

Adhesive labels, though also somewhat vulnerable to adverse environmental influences, can provide CDs with extra protection from scratches. The extra layer on printable discs likewise offers protection.

Scratches on the Label Side of Single-Sided DVDs
Scratches on the label side of single-sided DVDs are not likely to pose a problem. The metal layer so prone to damage in CDs is in the middle of DVDs. Its location makes this layer almost impervious to surface scratches; it is in fact unlikely to be affected by any but the deepest scratches—those deep enough to reach the center of the disc where the metal and data lie.

1. Handle discs by the outer edge or the center hole.
2. Use a non-solvent-based felt-tip permanent marker to mark the label side of the disc. Over time, some marking inks may penetrate the disk and reach the reflective layer.
3. Keep dirt or other foreign matter from the disc.
4. Store discs upright (book style) in plastic cases specified for CDs and DVDs.
5. Return discs to storage cases immediately after use.
6. Leave discs in their packaging (or cases) to minimize the effects of environmental changes.
7. Open a recordable disc package only when you are ready to record data on that disc.
8. Store discs in a cool, dry, dark environment in which the air is clean.
9. Remove dirt, foreign material, fingerprints, smudges, and liquids by wiping with a clean cotton fabric in a straight line from the center of the disc toward the outer edge. The reason for this is that any scratches that are made will be such that it will have a minimal impact on the ability to have its data read.
10. Use CD/DVD-cleaning detergent, isopropyl alcohol, or methanol to remove stubborn dirt or material.
11. Check the disc surface before recording.

12. For long-term storage store at temperatures between 39°F to 68°F with relative humidity from 20% to 50%.

     

     

1. Touch the surface of the disc.
2. Bend the disc.
3. Use adhesive labels.
4. Store discs horizontally for a long time (years).
5. Open a recordable optical disc package if you are not ready to record.
6. Expose discs to extreme heat or high humidity.
7. Expose discs to extremely rapid temperature or humidity changes.
8. Expose recordable discs to prolonged sunlight or other sources of ultraviolet light.
9. Write or mark in the data area of the disc (the area the laser “reads”).
10. Clean by wiping in a direction going around the disc. There was an item in the DO list that corresponds to this saying to wipe from the hub to the outer edge.

 For CDs especially do not:

1. Scratch the label side of the disc.
2. Use a pen, pencil, or fine-tip marker to write on the disc.
3. Write on the disc with markers that contain solvents.
4. Try to peel off or reposition a label.

Adhesive labels may be well suited for short-term disc usage (less than five years), and can even add a layer of protection from scratches and other potentially harmful contact. On the other hand, such labels are vulnerable to adverse environmental conditions: they can dry out or absorb moisture, and they can be affected by heat or cold even more than the disc itself. Such conditions may cause the label to delaminate. Disc manufacturers advise against using adhesive labels because they can create unbalanced disc spin, resulting in premature wear of the drive. If a label is used, it should be manufactured for use on CDs or DVDs, and an appropriate disc label applicator tool should be used to affix the label. The label applicator tool should center the label on the disc so as to maintain the disc balance as much as possible.