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CD-R discs are manufactured by injection-molding the 1.2 mm thick polycarbonate substrate that contains a spiral pre-groove. The dye layer is then spin-coated on the surface containing the pre-groove. A reflective layer is then sputtered over the dye layer, and a thin protective layer is spin-coated over the reflective layer. "Color" in the polycarbonate layer relates to the visual part of the spectrum, while the CD laser operates near 780 nm in the near-infrared. Consequently, the visual properties of the polycarbonate are immaterial. Modification of the infrared properties of the polycarbonate would degrade the read/write capabilities of the disc, and is not done. I do not pretend to be always right, but the above information is accurate, as a bit of common-sense thought would confirm. Jerry Media Sciences, Inc. > -----Original Message----- > From: Association for Recorded Sound Discussion List > [mailto:[log in to unmask]] On Behalf Of Don Cox > Sent: Monday, August 23, 2004 1:02 PM > To: [log in to unmask] > Subject: Re: [ARSCLIST] ? about Burning CDs for archives > > On 23/08/04, Mike Richter wrote: > > > Arguing this technology with Jerry is about as wise as disputing > > mathematical physics with Stephen Hawking - except that Jerry *can* > > communicate when one is not excessively simple. > > Well, Hawking recently admitted to being wrong about one of his major > theories, after about thirty years. > > I have seen no scientific evidence or tests here, only a blanket > out-of-hand dismissal of the possibility that there could be any > advantage. I don't know if there is an advantage, but the extra > manufacturing cost is small; so if there is an advantage, then black > polycarbonate would be worth while. > > People who are very certain about something are often wrong. > > Regards > -- > Don Cox > [log in to unmask]