Re: [ARSCLIST] DVD stability

[Joe_Iraci@xxxxxxxxx]

Hmmm. Long-life. What does that mean to the manufacturer?

I did test Verbatim DVD-R discs. These were discs from 2 to 3 years ago.
They were made in Singapore and use the metal-azo recording dye. I cannot
say how long they will last, since my testing was focused on relative
stability at elevated temperature and relative humidity (direct comparison
with other brands) and not specific lifetime determination. What I can say
is that I have tested 15 different brands of DVD-Rs and of those the
Verbatim disc ranked in the top 3. Mitsui brand also performed well.
Currently, I am testing a disc branded as Kodak (made in India) and halfway
through the testing it seems to be doing well.

I don't expect these discs to be anywhere near the longevity of gold metal
layer and phthalocyanine dye CD-Rs. However, the top brands have a good
chance of outlasting the technology and if stored under ideal conditions
(lower temperature, lower RH, in the dark, proper storage case, etc...)
will definitely outlast the technology.

Also note, of the fifteen brands tested, 6 did not survive the first aging
interval (21 days at 80 degrees C and 85% RH). One brand, I could not write
to at all. There are a lot of poor products out there.


Joe



             David Lewiston
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             erizon.net>                                                To
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             <ARSCLIST@xxxxxxx         Re: [ARSCLIST] DVD stability
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             13/04/2005 02:02
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             Please respond to
              David Lewiston
             <david.lewiston@v
                erizon.net>






Joe

I found your post most interesting. The latest long-life ad claim comes
from
Verbatim for their "metal-azo" DVDs. Were they included in your study?
Naturally I'm curious, wondering whether you can support or deflate their
claim.

I'm in the process of ramping up for a major archival project (NARAS has
given a grant of $20k to conserve my analogue recordings from many
countries) so naturally I'm anxious to make an informed decision about
media.

Many thanks.

David Lewiston
The Lewiston Archive, Recordings & Documentation of the World's Traditional
Music

>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