Peter Brothers wrote:
One of the primary failure mechanisms that needs more testing is
delamination. In my opinion, from review of the available data, there is
not enough reliable information on the stability and reactive properties
of
the glue used to bond the layers together. If someone has a good, quick
way
to test the glue stability, I would be pleased to pass it on to the
Commission.
Can anyone confirm that glue failure is actually a problem and DVDs are
delaminating all over the place. I have subjected 15 brands of DVD-R
discs,
7 brands of DVD-RW discs, and about 75 DVD movie discs to accelerated
aging
conditions. The total amount of discs tested was close to 200. Not one
disc
delaminated.
Claus Trelby wrote:
Just a suggestion.... I've personally stopped paying attention to
accelerated media testing... I find it useless... history always proves it
wrong...
Actually, accelerated aging can be a useful tool if the results are used
correctly. Actual lifetime numbers predicted via accelerated aging can be
very suspect. However, accelerated aging can provide useful information in
terms of comparisons between the relative stabilities of materials.
I must disagree that history has always proved accelerated aging wrong.
Accelerated aging has been used to correctly predict the dye fading in
colour photographs and the degradation of acetate based film. Some natural
aging testing has confirmed this. There has also been advancements in the
paper field that has produced an accelerated test that is strongly
believed
to mimic natural aging. A long-term natural aging study is underway to
confirm the accelerated results. I would not use accelerated aging results
as the sole factor in my decision making, but I would also not ignore the
information on the premise that it is always wrong. For the most part,
there has been no side-by-side natural aging studies to confirm that it is
always wrong or always right for that matter. It you have specific
examples
of "history proving accelerated aging is always wrong", I think it would
be
an interesting discussion for the list.
Joe Iraci
Senior Conservation Scientist
Canadian Conservation Institute
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