The following is a Plus Edition article written by and copyright by Dick Eastman.
Do you think your family photographs, home videos, and digital images of your genealogy documents are safe because you stored them on CD or DVD disks? Think again.
Here are pictures of two CDs that were stored by one of my family members. Both disks are less than two years old:
Notice the “flaking” in the metallic foil along the lower edge of the above disk. This music disk is now unplayable.
The second image is a bit more subtle, so I drew red arrows to point to the problems. Notice the two “holes” in the metallic foil of the disk. This particular disk still works today until the laser encounters one of the holes. Then it aborts. The remaining data or music is lost.
Do your disks have these problems? If they do not yet have the problems, will they develop similar problems in the near future? Many CD and DVD disks are going to suffer similar fates.
The life expectancy of all CD and DVD disks depends upon the processes that created the disks and recorded the information on them. Commercially-produced CD and DVD disks have the data already recorded on them at the time of manufacture. The data is sealed into the disk as part of the manufacturing process. Labels are printed directly onto the plastic surface. The experts disagree a bit over the exact life expectancy, but most agree that commercially-manufactured disks will last 25 years to perhaps 100 years or maybe even longer with no signal change or degradation IF PROPERLY STORED.
Using a home or office PC to record information onto a CD or DVD disk is an entirely different process with different life expectancies. The above pictures show CD disks that were recorded at home; that is, the blank disks were purchased at some office supply store, and the data was added long after each disk was manufactured. The manufacturing process of these blanks is quite different from that of disks created in factories with information already on them.
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