The question is, when it is wrong, why is it wrong?

With recording media, it seems always that a factor additional to those
considered in the test has been the culprit.  Identifying these, determining
which are significant, and deciding how to test them is an additional stage.

Steve Smolian

----- Original Message -----
From: <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, June 03, 2005 9:16 AM
Subject: Re: [ARSCLIST] Testing DVDs

> 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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