Re: [ARSCLIST] New CD Report NIST

[Steven Smolian <smolians@xxxxxxxxx>]

This is a question for Mr. Hartke:

Apart from your own report on CD testing, can you suggest a readily
available web source which discusses the same issues, preferably one which
does not come from a professional testing service?

Steven Smolian

----- Original Message -----
From: "Jerome Hartke" <jhartke@xxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxx>
Sent: Monday, December 13, 2004 3:14 PM
Subject: Re: [ARSCLIST] New CD Report NIST


> As mentioned before, BLER alone gives misleading results for accelerated
> aging as reported at http://www.mscience.com/longev.html
>
> Jerry
> Media Sciences, Inc.
>
> > -----Original Message-----
> > From: Association for Recorded Sound Discussion List
> > [mailto:ARSCLIST@xxxxxxx] On Behalf Of Joe_Iraci@xxxxxxxxx
> > Sent: Monday, December 13, 2004 10:07 AM
> > To: ARSCLIST@xxxxxxxxxxxx
> > Subject: Re: [ARSCLIST] New CD Report NIST
> >
> > I have performed a similar study that will be published in Restaurator in
> > early 2005 (I will pass on the reference to the list once it is
> > published).
> > Accelerated aging was performed on CDs, CD-Rs (various dye types),
> > CD-RWs,
> > DVDs, DVD-Rs, DVD-RWs.  Many (much more than the NIST study) different
> > types from different manufacturers were tested.  Results were based on
> > BLER
> > changes.  Conclusion was that the CD-R with phythalocyanine dye
> > outperformed all other disc formats.  A relative stability ranking of the
> > various formats was produced.
> >
> > The goal of the study was to assist individuals in making choices when it
> > comes to optical media.  Making a  lifetime prediction is time consuming,
> > expensive, and usually contains a lot of uncertainty.  I believe a more
> > practical approach is examining relative stabilities.  Any study that
> > provides information on how this media reacts is useful.  Granted
> > reactions
> > are occurring at higher temperatures and there is no guarantee that those
> > same reactions will occur at room temperature, but if you had to choose
> > would you trust media that withstood harsh accelerated aging (80 degrees
> > Celsius and 85% relative humidity for intervals up to 84 days) and still
> > had no E32 errors and low BLER or media that failed within the first 21
> > days under these same conditions.
> >
> > Yes, there are other factors to consider like writing speed and
> > compatibility issues, but the focus is on media stability in this case.
> >
> > In the above study, using either BLER or E32 errors would have led to the
> > same conclusions.  BLER alone can sometimes be misleading, but generally
> > not when it comes to monitoring degradation via accelerated aging.   As
> > long as both are monitored I do not see a problem using BLER. This
> > observation is based on the experience of aging and analyzing several
> > hundred discs.  Same applies to PI errors for DVDs.
> >
> > Joe Iraci
> > Senior Conservation Scientist
> > Canadian Conservation Institute