Re: [photo-3d] CD-Rs = 200 years?

[Brian Reynolds <reynolds@xxxxxxxxx>]

Tom Deering wrote:
> 1. Accelerated testing is all anyone can do, unless you want to wait 
> 200 years for your results.
> 

I didn't say accelerated testing wasn't any good, I said you had to be
carefull about how you apply it.

There are materials that have been used for over 100 years that can be
shown not to have faded.

> 2. Yes, the disks need to be stored carefully.  Slides, too.  Most of 
> us have basements that are dark, cool, and dry.
> 

Basements are also prone to flooding, and are not as available as you
might think.  I don't have one in NYC, and I know my brother in
Florida doesn't.

> 3. The comparison to ink fading is not useful. Digital data is 
> objectively good or it's not, regardless of who tests.  Fading is 
> subjective.
> 

At least for dye based CDs, the materials are similar to some (dye
based) inks.  In general dyes fade and pigments do not.

> 4. "hardly a disinterested 3rd party"?  What FAQ author on any 
> subject is not interested in the subject of the FAQ?  Why would they 
> bother?
> 

The reference you cited sells CD-R's.  By disinterested I meant
someone who would not directly profit from promotion of the
information that was being presented.

> 5. My sources do not quote references, but contradictory references 
> have not been presented, either.  I did not find "CD" on any web page 
> at http://www.wilhelm-research.com
> 

Wilhelm was given as an example of the type of testing and research
that is being done.  He does not publish all his findings on the web,
and he can not publish data that whoever paid for the testing wishes
to remain confidential.

> 6. Let's be practical. Even if the actual life is half the published 
> amount, a CD-R may be around long after the photographer is 
> forgotten.  How many of us can name one relative that lived 100 years 
> ago?
> 

My grandmother lived to 96.  My wife's aunt (or great aunt or
whatever) recently died at 102.

> If your great-grandchildren haven't discovered your CD-R and
> transferred it's contents to their wrist Cray, their progeny
> probably won't remember you or care.
> 

I don't think these materials will be readable when my children (of
whom I don't have any yet) want them, let alone great-grandchildren.
The hardware and software to read digital media changes to quickly,
and day to day use of this meadia shows me that it is not robust
enough to survive long storage.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
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http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
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