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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