> From: Rob Danielson <>
> Good find. Are you betting on the freezer because there's no telling
> what kind of dyes and quality control were used? The coming
> longevity tests may not tell us what we're aching to know if there's
> so much variability in the products. No more bargain discs for me.
> Would it be would be useful to know which companies are practicing
> quality control in making phthalocyanine dye, silver/gold metal
> products? Mitsui possibly? Anyone know the scoop here? Rob D.
I would think that one should be a little careful even with a freezer. I
know in my freezer that anything in there may accumulate frost with
time. And it does that while the product itself is dehydrated.
The tests done did not examine what freezing temperatures might do. For
all we know it might make it worse. It might be a lot better to
refrigerate rather than freeze. Or maybe even room temp is best.
When I last looked into this a few years ago I ended up getting some
Mitsui Gold disks, the kind designed for the slower record speeds. They
(and the HHb version) were the best ratings at the time. At the time you
could no longer find the lower capacity disks, and everything at most
supplies was rated for high speed burning. In order to get high speed
burning the coatings have been somewhat compromised and pit shape
suffers. But you must burn at the speeds the disk was designed for.
Going outside the optimum speeds for that disk will result in higher
error rates. In fact I've found that even with high speed disks using to
lowest speed they are rated for get's the most consistent results.
The slow burn Mitsui's were discontinued at the time I got them. I
assume they reformulated to faster burn for the ones available now. It's
not at all clear in the paper what they were using. The HHb blanks
appear to be the same as Mitsui's if not made by them.
Of course I also avoid this issue somewhat by using 3.5" optical disks
for one leg of my archiving. Their coating system is much better than
any of the CD types. CD's are now often called optical disks, but I
consider them different, and not really archival. Note in the paper that
their idea of archival CD's was 10 years or so. Regular optical disks
are even more durable than MD's, up to maybe 100 years. Of course there
will be nothing to read them by then, but that's a different story.
Walt
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