John from FL writes:
Is there one brand of CD that is considered better than others? Also, would a DVD be better to record information on?
This is a question not a lot of people think of because they assume CD/DVDs will last forever. Guess what? It’s not true! Regular CDs and DVDs degrade with time and exposure to the elements. So what do you do to keep them as long as possible?
Let’s start with what you can do with regular CD/DVDs.
- Use only CD-R/+R or DVD-R/+R. -RW discs designed to be rewritable are not suitable for long term storage.
- Limit exposure to air and sunlight.
- Store in a proper CD/DVD case – not a paper envelope.
- Wipe the bottom of the CD/DVD clean of any fingerprints or residue with a lens tissue or clean microfiber cloth.
- Make two copies! It’s always better to have a backup.
So what CD/DVDs do you want to buy if you’re concerned about long-term reliability?
When looking for archival CD/DVDs, you should pay attention to what the reflective layer is made out of and what dye is used. This information can be found in the manufacturers specifications for the disc.
The best discs are made using gold as part of the reflective layer. You can identify them by the manufacturer indicating just gold is used. They can be found online for $2.00 a piece in packs of 25. These are rated for 300 years of storage in archival grade storage conditions.
The second best style of CD/DVD are gold/silver hybrids which will mention both gold and silver, and can be found online for a bit cheaper (usually $1 to $2 per disc) in smaller packs.
The lowest quality of archive discs will be silver only. These are better than traditional discs, but not by that much. Usually these cheaper discs are sold for under $1.00 each.
Each of the above types of reflective layers can be made using different types of dyes. The best type of dye to look for is Phthalocyanine, the second best is Azo and the worst performing is Cyanine.
As far as CD vs DVD, there isn’t a difference in physical media that I know of in terms of lifespan – though by nature of there being less information stored on a CD it may be better to lose less of the “total” if you have 10 CDs and one goes bad versus all the information on one DVD. If it was me, I still might just make 3 copies of the same DVD – just in case.