The Harrow Technology Report: "Care & handling of CD's... The independent National Institute of Standards and Technology' has gone into great detail to analyze the different types of disks, their likely lifetimes, how storage conditions can affect their integrity (for example, don't store CDs/DVDs flat for long periods of time; store them in a case, vertically), and the safest methods for labeling and cleaning these polycarbonate packages that can hold your vital business or personal data, or the pictures of your kids.
For example:
- Did you know that the polycarbonate layer(s) that make up the bulk of these disks absorbs moisture, oxygen, and various environmental pollutants? These can eventually oxidize the reflective aluminum coating in stamped (ROM) disks (it's called 'disk rot'), and so reduce or destroy the disk's readability;
- Don't use 'RW' or 'RAM' rewritable optical disks for any archiving, as their dyes are far less stable than those used in the '+R' and '-R' write-once variety; and
- All types of CDs (as opposed to DVDs) are particularly fragile on their 'top' or label side. That's because the reflective metal layer is directly under the disk's top surface, which (surprisingly to most of us) is only a thin lacquer coating! Therefore using a ball point pen or anything sharp or hard on the label surface is discouraged.
Similarly, harsh solvent-based markers (water or alcohol-based markers are apparently OK, but not those based on toluene or xylene) can penetrate the lacquer and damage the essential reflective metal beneath it. (DVDs on the other hand DO have a top layer of thick polycarbonate; the reflective layer(s) are actually at the center of the disk's thickness.) If in doubt, just label the hub area which doesn't contain any data at all.
This paper is interesting and important reading, especially if "your data is your (or your businesses') life." But even if you don't wade through the entire report, do check out the one-page "Quick Reference Guide for Care and Handling" at http://www.itl.nist.gov/div895/carefordisc/onepage.pdf."
For example:
- Did you know that the polycarbonate layer(s) that make up the bulk of these disks absorbs moisture, oxygen, and various environmental pollutants? These can eventually oxidize the reflective aluminum coating in stamped (ROM) disks (it's called 'disk rot'), and so reduce or destroy the disk's readability;
- Don't use 'RW' or 'RAM' rewritable optical disks for any archiving, as their dyes are far less stable than those used in the '+R' and '-R' write-once variety; and
- All types of CDs (as opposed to DVDs) are particularly fragile on their 'top' or label side. That's because the reflective metal layer is directly under the disk's top surface, which (surprisingly to most of us) is only a thin lacquer coating! Therefore using a ball point pen or anything sharp or hard on the label surface is discouraged.
Similarly, harsh solvent-based markers (water or alcohol-based markers are apparently OK, but not those based on toluene or xylene) can penetrate the lacquer and damage the essential reflective metal beneath it. (DVDs on the other hand DO have a top layer of thick polycarbonate; the reflective layer(s) are actually at the center of the disk's thickness.) If in doubt, just label the hub area which doesn't contain any data at all.
This paper is interesting and important reading, especially if "your data is your (or your businesses') life." But even if you don't wade through the entire report, do check out the one-page "Quick Reference Guide for Care and Handling" at http://www.itl.nist.gov/div895/carefordisc/onepage.pdf."
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