Monday, May 9, 2011

Hitting the Mother Load.

Hello again one and all.

            In my last post I mentioned using 24K Gold as way of preserving data of every description, but not in any solid form like jewelry.  The gold I am talking about is part of the DVD/CD discs that we use in the studio for storing the data on.  Actually those discs also have silver in them as well.  No your eyes are not deceiving you.  The Century Archival discs do have both of those precious metals in them, but you don’t need a safe or a bank vault to store them in.  So what say we clarify this a little, and look at how a DVD/CD is constructed and then it might make a little more sense.

            Believe it or not the basic DVD/CD is made in a similar fashion like the old LP records.  LPs’, a polyvinyl chloride material, were literally pressed between two heated metal dies, where DVD and CDs’ are injection molded like countless other pieces and parts we use every day.  Their life begins as a glass plate that is first coated with a photosensitive compound.  This is then exposed like you would a photograph creating a negative image.  When the plate is developed, it leaves a three dimensional image on the glass.  Which is only is only125 nanometers thick.  For those of you not into metrics that is .0000393701 inches.  The next step immerses the glass in a nickel-vanadium solution for seventy minutes; resulting in a metal disc that becomes the injection master.  Up to now it has been a hands’ on approach, but that is about to change.

            The master disc is now very carefully inserted into injection molder, and automation takes over.  The base layer of the disc is a polycarbonate material much harder than PVC used for LPs’.  After the disc hardens, it is sent to a coating machine that lays down a very thin layer of aluminum.  Next comes a layer varnish.  This serves a dual purpose; first it protects the aluminum, and second it gives the disc a printable surface for silk-screening the label.  This automated injection process allows for a production rate of 100, 000 discs a day, either prerecorded or blank media for burning later in your computer.

            At this point all similarities cease, since the Century Archival Discs’ have a pure silver layer instead of aluminum because it offers a more mirror like reflecting surface for the laser to read with.  However it to is affected by atmospheric corrosion and degradation, which the varnish is incapable of preventing.  So now the silver is plated with a layer of 24K Gold whose sole purpose in life now, is to protect the silver.  The simple reason is that gold is impervious to all known corrosives save one.  That compound is a blended acid solution known as Aqua Regia.  Trust me when I say, your DVD/CD’s collection will never come anywhere near it it.  The last bastion of defense of these discs’ is a hardened layer on the bottom, the part the laser sees through. The resin used for this, when hardened, is up to 100 times stronger than the disc itself.  This technology allows you to drop your discs (accidentally of course) and they will still play, even with the deepest of scratches, mars, and fingerprint smudges.
            All said and done, these discs’ offer a way to preserve all that is important to you, your family or you’re your business for the next five generations, or more.  It is a reasonably safe bet that the discs we burn today will still be readable for the next major storage innovation like Spoke’s passive data blocks.  Maybe?