SV: [AV Media Matters] medialine CD-R permanence article

[lars.gaustad@nb.no]

Charles Repka writes:

"As a general rule in disc manufacturing, ( and this is true for
vinyl LP's, Laserdiscs, CD's, DVD's etc) the inner diameter of the
disc tends to have fewer mechanical problems caused by plastic flow
during the pressing process.  The farther you get away from the
center, the more problems you see.  The higher BLER at outer
diameters may be due to problems with the servo tracking of the
wobble groove on the player used.The wobble groove itself may also
be slightly deformed at outer diameters.  The deformation, in turn,
can be caused by pressing problems when the blank was pressed or by
problems in the mold used.  There are a lot of inter acting factors
here and it is not wise to just blame the dye."

Why is this BLER increase then related especially to the
ptalocyanine dye discs? If pressing or servo tracking problems is a
factor you should expect an equal problem with all dyes and
pressings.

lars gaustad
FilmSoundVideo-dep
Media Lab
National Library of Norway
N-8607 Mo i Rana
phone:+47 751 21 154
fax:     +47 751 21 222
mobile:+47 959 48 393
e-mail: lars.gaustad@nb.no
           larsg@monet.no