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[filmscanners] RE: How to label CD backups >Tim



First labels again

there are potential long term problems with labels and their glue/acidic
paper etc, but the biggest problems are short term.

1. Get them wet (spill coffee, a sprinkler goes off, a pipe bursts) and you
won't be able to play the CD and will probably damage it getting the label
off.

2. All recorded CD's have a certain level of write and read errors. These
errors slowly increase over time as the CD deteriorates (there is triple or
quadruple redundancy built into the recording format - I forget which -
which compensates for this until the CD reaches a point where it won't
play.) Damage - eg scratches etc increase these error levels more rapidly.

I've lost the graph I had, but applying labels - even carefully applied
circular ones, and certainly asymmetric ones MASSIVELY increases the read
error right from the start - by a factor of something like 15 or 20 times
(as I said, I've lost the data I was given at the workshop).

So, "naturally" occurring errors might lead to the CD being unreadable in
say 50 years. The imbalance caused by the label reduces that dramatically.

Now, cases - the conservation guys recommend jewel cases made of
polypropylene or polycarbonate, CD's stored on edge. I don't think plastic
sleeves came up. I'm not sure you could find any that are archival?

They dislike paper slip cases - again, getting wet/disaster recovery - in a
flood you may not get to your CD's for a while, meanwhile they are sat stuck
together in wet paper. Jewel cases will drain naturally. Plus, CD's can
warp - being stacked together, perhaps under pressure, in sleeves could
increase or cause that. For all their annoyances, jewel cases are actually
pretty good for storing CD's

As Conservators like to point out, more stuff is lost to fire, flood,
accident or theft (see the damage to the "james brother of jesus" ossuary
this week...) than by deterioration from long term storage in poor
conditions, though you shouldn't ignore the latter of course.


tim


> -----Original Message-----
> From: filmscanners_owner@halftone.co.uk
> [mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Julian Robinson
> Sent: Tuesday, November 05, 2002 4:33 PM
> To: tim@KairosPhoto.com
> Subject: [filmscanners] Re: How to label CD backups >Tim
>
>
> Tim - do you have any thoughts on the storage problem resulting from this
> work?  Are plastic sleeves OK and better/worse than jewel cases?  If so,
> what plastic?
>
> Julian
>
> At 04:48 06/11/02, you wrote:
> >I've posted ad infinitum the advice about storage etc we were given by
> >scientists from the Canadian Conservation Institute who were doing this
> >testing (The Longevity and Preservation of Optical Media...) -
> I'm sure you
> >can find it in the archives if you hunt for CD's!
> >
> >tim
>
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