Limited contact cleaning with mild solvents such as isopropyl alcohol or methanol is permitted, as these solvents evaporate quickly and will not dissolve the polycarbonate. They may, however, dissolve or damage labels or optional coatings on the label side of the disc. The effects on optical discs of magnetism, X-rays, microwaves, and radiation can be summarized as follows:. Optical discs should be kept in individual storage containers until used and returned to those containers immediately thereafter.
Typical storage containers, as listed below, isolate and help protect discs from airborne contaminants and other foreign material. They also help buffer rapid environmental changes that can cause stresses to the disc. Cases are designed to keep surfaces of the disc from contact with the inside of the case. Only one disc should be placed on the hub or each hub in the case.
To remove the disc, one should press down on the hub tab while holding the outer edge of the disc with the fingers and then lift up. Bending the disc while lifting it off the hub tab should be avoided. For long-term disc storage, it may sometimes be prudent to remove the label insert or booklet from inside the case and attach it to the outside, perhaps in a sleeve.
In theory, the paper can attract moisture and produce higher moisture content in the case. The paper may also spread moisture by contact with the disc. This recommendation is based on no specific tests of the effects of paper inside a case; it is merely a consideration—one that takes on added significance with large amounts of paper inside a disc case and higher-than-recommended humidity conditions.
Anything on an optical disc surface that impedes the ability of the laser to focus on the data layer can result in missing data as the disc is being read. Fingerprints, smudges, scratches, dirt, dust, solvents, moisture, and any other foreign material can interfere with the ability of the laser to read the data. They can also interfere with the ability of the laser to follow the data track in the disc. Light scratches and fingerprints are very common, and while they both can impede laser reading, their effects on the disc are somewhat different.
Scratches affect discs differently depending on the side of the disc affected, the severity and direction of the scratch, and the type of disc. Scratches generally cross data lines or tracks on the disc, and how bad deep and wide they are will determine the extent of interference with laser focus on the data.
Small or occasional scratches will likely have little or no effect on the ability of the laser to read the disc, because the data are far enough below the surface of the disc that the laser is focused beyond the scratch. 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 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 see page 23 , 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 are not likely to pose a problem. 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.
Fingerprints, smudges, dirt, or dust on the laser reading side of the disc can disrupt laser focus on the data even more than a scratch can. Dirt or dust on the disc will block or reduce the light intensity of the laser.
If severe enough, it will cause the disc drive to miss data as the disc is being read. Fingerprints, smudges, or dirt cover wide areas of data and will cause the laser beam to go out of focus or lose intensity. They will also cause widespread misreading of data along the data lines or tracks, to an extent that exceeds the error correction capability of the disc drive.
Dust can also spin off into the disc drive and collect on the laser head or other internal components. Fingerprints, smudges, and dirt are easier to remove than scratches; it is simply a matter of cleaning them off. To summarize, the effects of scratches versus fingerprints and smudges on the laser reading side of a disc include the following:.
CDs and DVDs, or their containers, are labeled in some form or fashion so that they can be identified and organized. When labeling a CD with markers, the composition of the ink in the marker and the style or design of the marker should be considered. 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 categories, 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 fine-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 recommended for CD labeling. You will need a region free DVD player.
Old firmware - If it's an old DVD player that stops in the middle of a movie or new DVD won't play, then the old firmware may be the cause. The encryption keys in an old drive, whether your PC or Home Theater system, may be out of time and therefore fail to decrypt many newer DVD titles that have special and advanced protections on them.
You may check if the manufacturer provides an update or convert the new DVD movies. You're suggested to refer to the DVD copyright laws in your country before doing so.
Donna Peng's fascination with multimedia began at an early age - shortly after she licked the physical disc and then she's been obsessed ever since.
P I agree with Tex. This new technology isn't as great as people make it out to be When Neo talks to the Oracle and when he talks to the Architecht. The people that encode these films are total muppets. I have a DVD where the pause is mid-sentence!! It's totally out of order. There are machines out there that can minimise the affects of layer break change.
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