Re: [ARSCLIST] DVD stability

[Joe_Iraci@xxxxxxxxx]

A paper will be published shortly in Restaurator that summarizes work that
I have done which compares the relative stability of various optical disc
formats: audio CDs, CD-Rs (azo, cyanine, phthalocyanine dyes with silver or
gold metal layers), CD-RWs, DVD movie discs, DVD-R, and DVD-RW.

In this study, many more disc brands and types were examined than what is
presented in the NIST study. In particular, 11 different brands of DVD-Rs
where tested. I am also currently testing 4 more brands. In summary, the
DVD-Rs faired better than CD-R (azo) and CD-R (cyanine) but no where near
the stability shown by CD-R (phthalocyanine). DVD-Rs are not made with gold
metal layer and phthalocyanine dye. Instead, an azo or cyanine based dye is
used that shows less stability under elevated temperature and relative
humidity and when exposed to light. I will post the reference to this list
once the paper is published.

Also, the NIST study shows good stability of sample D2, but the aging is
for only around 420 hours. My testing has shown that some samples show good
stability for the first 500 hours of testing (at 80 degrees C and 85%
relative humidity), but then degraded significantly afterwards. This was
particularly the case with cyanine dye discs.

Joe Iraci
Senior Conservation Scientist
Canadian Conservation Institute



Further Considerations:

Lacking any further information, and if committed to optical
media, Scenario 1 is the only real choice.  However...

NIST published the results of DVD+/-R HALTs (Highly
Accelerated Lift Tests) in the Journal of NIST, Volume 109,
Number 5, September-October 2004, "Stability Comparison of
Recordable Optical Discs - A Study of Error Rates in Harsh
Conditions".  One of the samples in the study called "D2"
showed very promising archival properties comparable to
archival CDs.  I've made several attempts at contacting the
researchers at NIST who wrote this report, but have not
succeeded in learning the type of DVD corresponding to "D2".
The report states, "Unfortunately, it is very difficult for
customers to identify these more stable media." (page 523
in the Journal article).  Unfortunately, NIST does not shed
any light on how to identify these DVDs either.

This is one of the most valuable reports I've seen to date
on DVD archival properties, and is very important for
archives who are committed to optical media for certain
projects.

If anyone knows more about this NIST report and the actual
DVDs used for the tests, I would greatly appreciate that
information.