[ale] OT: Labels on CD-Rs

[Jeff Hubbs]

FWIW, my Imation CD-Rs seems sturdier than that.  And, both the thin
metallic-looking layer that pulled off and the plastic that it came off
off both look like they've got pits (they both diffract light) - and you
can tell on the plastic itself where the burn stopped, so IMHO there is
dye still there.  

I did find something on Anandtech saying that a 50x CD drive can spool
up to 10,000RPM, and my mechanical intuition tells me that anything you
spin up to those speeds had better well be balanced.  CD label hits go
to great pains to enable you to center the label, but in this case, the
label was about 4" long and pushed about as far to the edges as it could
be.

- Jeff

On Wed, 2002-12-04 at 02:35, GregJohnson.Com wrote:
> Mmm, methinks you're getting standard mileage here...
> 
> AFAIK, all the CD-Rs I've played with are constructed consistent with your
> description.  (i.e. hunk of plastic, miniscule layer of dye, and microscopic
> layer of plastic on top to contain said dye.)  Based on my reading and
> limited personal experience, a quick way to destroy any CD-R is to try to
> peel a label off.   Personally, I'm surprized you have any dye left at all.
> (BTW, pedantically speaking your dye is most likely Phtalocyanine
> http://www.xdr2.com/CDR-Info/Dye.htm, as alumium is only used in
> mass-produced "stamped" CDs)  Disclaimer: Nearly every disc I've ever burnt
> was "a really cheap CD-R"
> 
> Spitballing, the CD-Rs have pre-positioned pits/lands, but unlike a pressed
> CD the information is actually in the dye, as opposed to the alumium/gold
> merely serving as a reflector for the information in the plastic. Thus, no
> joy after damage.
> 
> My impression of the explosion issues was that it took a material disc
> defect (crack, flaw) or serious mis-balance (big lable on the outer edge)
> for this to become plausible.  I'm sure this'll get answered in other mails,
> but in case it doesn't is there any public reporting on the "Sharpie
> threat?"
> 
> My $0.02.
> 
> -Greg
> 
> 
> ----- Original Message -----
> From: "Jeff Hubbs" <hbbs at attbi.com>
> To: <ale at ale.org>
> Sent: Wednesday, December 04, 2002 1:42 AM
> Subject: [ale] OT: Labels on CD-Rs
> 
> 
> > I had a couple of rolls of film developed at Wal-Mart today and I've
> > started having a CD made whenever I take film in; keeps me from having
> > to scan prints and it's not all that expensive.
> >
> > Anyway, I picked up my stuff and the CD - a Memorex CD-R - and they had
> > stuck a roughly 1" by 4" rectangular printed adhesive label on the back
> > of the CD-R.
> >
> > Now, back in the day, I know you could do that and it was no big deal,
> > but now that we have 52-time and 58-time CD drives, it's my
> > understanding that you can't even get too heavyhanded with a Sharpie
> > anymore and that you in fact run the risk of having the CD-R shatter in
> > the drive.
> >
> > Anyway, when I got home, I saw the label and said, this has got to go,
> > so I started to peel it off and...whoops, off comes a roughly 3cm by 3cm
> > patch of the the white CD backing, with the aluminum on one side of
> > it!!!!  Left behind was laser-etched tinted transparent plastic!!
> >
> > It has been my understanding that a metal-less CD can actually be read,
> > however, I think that the slightly-pulled-up aluminum around the ragged
> > edges of this hole in the backing makes it impossible to read - I tried
> > it in several drives.
> >
> > It occurs to me that this must be a really cheap CD-R that has the
> > reflective coating under what appears to be no more than a layer of
> > paint.  I want to bring my negs back to get them to burn me a new CD-R,
> > but I think I'll bring them one of my own blanks.
> >
> > So am I right to have tried to remove the label?  I didn't even want to
> > put it in a drive because I could imagine the vibration that would set
> > up and that's not a good thing to do to a hard drive, bolted in just
> > below.
> >
> > - Jeff
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> > Ale at ale.org
> > http://www.ale.org/mailman/listinfo/ale
> 
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