On Tuesday, June 30, 2009 11:30 AM, Steven Smolian wrote:

> Is there a reliable recordable DVD for long term storage, 
> independently tested?
>
> How does this compare with the anticipated lifespan of 
> gold-reflective CDs?

On the near horizon there may be a new family of optical
media that is mechanically etched directly into the media
rather than "burned" into an organic dye.

These new optical discs will require a special "etcher",
but the etched disc will be playable in a standard CD,
DVD or even Blu-Ray player.

Estimated life spans could be on the order of millennia (far
outliving the devices used to read the discs).

I've heard from the manufacturer that they can etch a disc,
place it in an autoclave (at temperatures high enough to
curl a normal polycarbonate CD or DVD), remove the etched 
disc from the autoclave, let the disc cool, and then read 
it without difficulty.

I hear these new "etched" optical discs are going into 
beta test (blanks and etchers) later this year at a handful
of select sites.  I hope to visit their manufacturing plant
later this summer.

If you need something equally archival right now, I've had
chemically etched glass CDs (using a photolithographic 
process) produced for my clients.  These are not inexpensive,
on the order of 10-15x the cost of a MAM-A disc.  Aside from 
the fragility of glass, these chemically etched glass discs 
probably have lifespans on the order of millennia.  If the
reflective layer ever fails, you simply recoat the disc.
There are no layers to delaminate.  And they are highly
scratch resistant.  Of course, once again the media will 
outlive the equipment to read the media.

Eric Jacobs

The Audio Archive, Inc.
tel: 408.221.2128
fax: 408.549.9867
mailto:[log in to unmask]
http://www.TheAudioArchive.com
Disc and Tape Audio Transfer Services and Preservation Consulting