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ARSCLIST  January 2010

ARSCLIST January 2010

Subject:

Re: quality of HHB CD-Rs?

From:

Jerry Hartke <[log in to unmask]>

Reply-To:

[log in to unmask]

Date:

Thu, 28 Jan 2010 17:49:12 -0500

Content-Type:

text/plain

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text/plain (160 lines)

Joe's inputs are helpful and accurate. They are supported by an old study
done at Media Sciences found at http://www.mscience.com/cdrfail.html .

I might add Reason #5: The blank disc had flaws unrelated to the dye,
pregroove, or metal layer, such as unbalance, eccentricity, and tilt.
Details may be found at http://www.mscience.com/whyfail.html .

An old analysis of degradation is at http://www.mscience.com/longev.html .

A key observation is that quality is not related to readability. A newly
written disc that is faulty may be readable in one or a few drives but not
in every drive. Its owner finds that it reads o.k., and assumes it is good.
Ten years later, when it is loaded into a completely different read drive,
it fails, and the problem is erroneously assigned to degradation when, in
fact, the disc was bad all along.

Error rate tests may be helpful, but BLER alone is not a good quality
indicator for reasons described in the last of the three white papers listed
above.

Jerry Hartke
Media Sciences, Inc.
Dedicated to Quality Since 1985

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
> Sent: Thursday, January 28, 2010 9:00 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] quality of HHB CD-Rs?
> 
> There are a number of reasons why CD-Rs and DVD-Rs fail.
> 
> 1.  Poor handling.
> This can lead to physical damage to the discs. Some damage can be
> compensated for by the error correction system, but damage such as
> breakage
> or widespread delamination cannot be repaired.
> 
> 2.  Wrong storage enclosure.
> This relates to poor handling. The wrong storage enclosure leads to
> scratching, provides poor physical protection for the disc, and can
> chemically interact with the disc.
> 
> 3.  Chemical degradation.
> This is accelerated by high temperature/relative humidity storage
> conditions and poor manufacturing. The main concern are the dye AND the
> metal reflective layer. Yes the metal reflective layer is very important
> and it is not just the dye that determines the stability of the disc. If
> the protective layer in CD-Rs is poor or the adhesive used to bond DVD-Rs
> is chemically active, then the metal reflective layer can oxidize and lead
> to unplayable discs. You can eliminate oxidation of the metal layer by
> choosing gold metal layered discs. You can eliminate dye degradation by
> choosing the phthalocyanine dye which is very stable to heat, humidity,
> and
> light. These factors will affect cyanine and azo dye discs. However, I do
> not see light as an issue unless you leave azo and cyanine dye discs with
> the dye side facing up and exposed to a UV emitting source for several
> months, 24/7. Obviously, not the best way to store discs. If stored in
> jewel cases and on a shelf, light plays no role in the degradation.
> 
> 4. The discs were never really recorded properly in the first place.
> There are many reasons for creating a disc that is not properly recorded
> e.g. not finalizing the disc, but I would like to focus on error rate. If
> the disc was recorded with a high error rate initially, then failure can
> occur quickly. A little bit of chemical change in the dye or metal layer
> or
> some scratching or other damage may push the errors over the correctable
> limit and problems or complete failure can occur. If the discs were
> recorded with a low error rate initially, the discs have plenty of
> headroom
> to absorb damage before problems become evident on playing.
> 
> In the research on optical media that I have performed over the last 10
> years, I have recorded many different discs, many different brands, using
> many different drives, and at many different speeds. Ten years ago, you
> would have compatibility issues - one drive would record a disc with a
> high
> error rate, whereas another drive would record the same brand of disc with
> a very low error rate. Nowadays, this is much less of a problem, as almost
> any disc burns well in almost in new or fairly new drive. Exception - some
> dual layer DVD-Rs. In some recent experiments, some brands could not be
> recorded with an error rate below the standard limit or even close to the
> standard limit, regardless of recording speed, recorder type, or day of
> the
> week.
> 
> From my experience, I believe that the disc failures we hear about are
> primarily due to point #4. Unfortunately, in the past, when the propensity
> to record discs with high error rates was more likely, no one tested their
> recording system (disc brand, software, recorder) before actually
> recording
> discs to ensure that low error rate discs were being produced. It was
> assumed that the discs were okay because they could be read right after
> recording - not knowing that they did have a high error rate and on the
> verge of failure.
> 
> So, I would go back into your collections and randomly check those early
> discs. Have an error rate test performed - by a company or purchase a low
> cost tester. By all means create a backup on hard drive (and back up that
> hard drive). However, don't assume that all CD-R and DVD-R are very
> unstable and about to be lost forever.
> 
> 
> Joe Iraci
> Canadian Conservation Institute
> 
> 
> 
> 
> 
>              Shai Drori
>              <[log in to unmask]
>              NET.IL>                                                    To
>              Sent by:                  [log in to unmask]
>              Association for                                            cc
>              Recorded Sound
>              Discussion List                                       Subject
>              <[log in to unmask]         Re: [ARSCLIST] quality    of    HHB
>              >                         CD-Rs?
> 
> 
>              01/28/2010 12:56
>              AM
> 
> 
>              Please respond to
>               Association for
>               Recorded Sound
>               Discussion List
>              <[log in to unmask]
>                      >
> 
> 
> 
> 
> 
> 
> I don't have the discs on hand anymore but when you asked for info on
> them from the burner it would say what glass was used to press them and
> what manufacturer. The first ones were definitely Mitsui, the later
> batch was if I remember correctly memorex (plasmon). BTW gold or regular
> your biggest problem is not the reflective surface but hte dye itself.
> UV light from neon lights kills them very early in life, even the higher
> end expensive ones. COPY your cd's, even the gold archival ons ASAP. HHB
> is not as well known in the US as it is in Europe. Some stuff they make
> some they rebrand (like hardware from Marantz, cd's from Mitsui etc.).
> Shai
> 
> Lou Judson wrote:
> > No proof. But common enough knowledge that I never bought any. If not
> > outsourced, where was their factory?
> >
> > <L>
> >
> > On Jan 27, 2010, at 11:11 PM, Alex Tomlin wrote:
> >
> >> Worldwide?... Proof?
> >

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