The Ways Recordable DVD's and CD's Can
Fail
(I will be adding more detail to this section later.)
I thought CD's and DVD's were nearly indestructible until I
started researching the issue. After I started checking into it, I
found a number of pieces of evidence that the data on recordable
discs can indeed self destruct over a short period of time.
A commercial DVD of a movie is PRESSED from a glass master disc.
Thus, the reflective surface of the disc actually has little pits in
it which the laser beam reads. This type of disc can last a very
long time under proper conditions.
A recordable disc does not have any real pits. The reflective
surface of the disc is coated with a dye which either evaporates and
changes color or creates a bubble when the laser beam writes to it.
This type of disc may not last nearly as long for the reasons below.
I have talked to a rep at the factory that makes archival grade
discs. He explained several ways that a recordable DVD (or CD) disc
can fail.
A recordable DVD is made by sandwiching a dye coated reflective
layer between two plastic layers, along with various coatings and
glues.
Failure mode # 1: OXIDATION
- I found out that the plastic part of the disc is not waterproof,
despite what we might think. Water vapor can seep through the
plastic over time. Once that happens, it can cause oxidation of the
reflective surface. If the reflective surface is made of a material
that can oxidize, it can become unreadable. Aluminum can corrode.
Silver can tarnish. The best way to
prevent oxidation is to use a material that cannot oxidize. The
best material for that is PURE GOLD. So, an archival grade disc
should have pure gold at its core. Not just a gold color, real
gold. Our discs have a core of pure gold.
Failure mode # 2: DYE FAILURE
- The chemical dyes used in recordable DVD's intrinsically go
through chemical reactions over time that change their color and
reaction to the laser beam. Certain dyes have been proven to have a
shorter life span and others a longer life span. The worst ones can
change in just a few years to the point that the disc is
unreadable. How do you know which is which? The only way is to
look at documented accelerated aging tests on the media. If you
want a buzzword to look for, go for Phthalocyanine (tha-lo-sy-a-neen).
According to my research, this is the best available. However, I
believe this applies only to CD's. Make sure the vendor is
really using this dye, and not just putting it on the marketing
materials. An archival grade disc should
use premium long life dye. Our discs have premium long life
dye. In the case of CD's, our discs use Phthalocyanine, and
the manufacturer we use owns the world wide patent on this chemical.
Failure mode # 3: BONDING FAILURE
- As mentioned above, the DVD is produced by bonding two plastic
discs together with the reflective surface, the dye, coatings, etc.
Some manufacturers don't use as high quality bonding agents as
others. Also, the 'glue' doesn't always extend fully to the edge of
the plastic discs. So, if the disc has bonding problems, and you
drop it on its edge, it might delaminate. This could cause it to
become unreadable. An archival grade disc
should use premium bonding agents and edge to edge coverage.
Our discs use premium bonding agents and edge to edge coverage.
Failure mode # 4: SCRATCHES
- If you've used recordable DVD media very much, you probably know
they're extremely susceptible to scratches. Put enough scratches on
the disc, and it will become unreadable. And, it doesn't take too
many to make that happen. The way to prevent this is by careful
handling and with a scratch resistant coating.
An archival grade disc should have a
scratch resistant coating. Our discs have a scratch resistant
coating.
Failure mode # 5: PRODUCTION QUALITY
- I was told that many name brand disc sellers bid the production
out to the lowest bidder. There aren't many DVD and CD factories in
the world. But, an archive grade disc is not likely to come from
the lowest bidder. Also, some of these brands change factories from
time to time as they get new bids. Therefore, the quality may vary
from batch to batch. An archive grade disc
should come from the same factory all the time which should maintain
world class quality control. Note, I didn't say the
owner of the brand had to manufacture the discs. But it is
essential that they get their discs from a world class factory.
Our discs come from the same factory all
the time which maintains world class quality control.
You WANT the GOLD. You NEED the
GOLD. Get it NOW!
You know you want it! Your data needs to be secure.
And, you don't want to worry about it. Click over to the
BUY! page and get your own GOLD. You
can worry less knowing that you've entrusted your data to the best
recordable DVD and CD media in the world!
Our World Class Manufacturer
My world class manufacturer is none other than Mitsui
Advanced Media - America (MAM-A). Take a look at the
various links on their website
http://www.mam-a.com/ . Browse around their website.
I think you'll be impressed. These are the only kind of DVD's
I'm entrusting my videos to in the future. I would say the
same for data.
I'll be adding more data on this later.
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