RE: [Videolib] Disc Repair Procedures

James Scholtz (jimscholtz@sdln.net)
Tue, 26 Jun 2007 12:08:06 -0500

Hi Jim Scholtz here - just my 2 here. I feel that watching the DVD is a
waste of time. A scratch on a DVD or CD doesn't necessarily mean the disc
won't play or that repeated cleaning/repair will remove the scratch. There
are units produced by RTI, Azuradisc and others that measure the amount of
damage and tell the user if repair is possible or not (about $3000+). To
tell you the truth, at our library we use a JFJ single arm unit and an RTI
Eco Smart unit with just using visual inspection. We use a patron comment
form to assess damage - if 2 patrons realize the same type of damage and we
can't get the scratches out, then we discard the disc (and/or re-order).
There is much difference in DVD players, not necessarily associated with
purchase price - some of the $59 units from Walmart play damaged discs
perfectly while a $600 Sony DVD recorder unit will reject the same disc.
Also, there are more discs than you think that come from the factory with
'pixilation' and other playability problems. Sometimes one cannot tell just
by looking at the disc if it will play or not. So I think that doing your
best to repair the scratches and using patron comments as to whether to
discard is the best/cost-effective option.

Just some observations on disc repair: A DVD is more like an LP record than
a computer disc - the physical dimples on the DVD are similar to the grooves
on a record disc. A scratch on a record disc that followed the groove
closely was always more of a problem that a scratch perpendicular to the
groove - depth of scratch was also conditional. Smudge scratches caused big
problems. A scratch in the polycarbonate layer of a CD/DVD causes the laser
beam to be refracted at a different angle. Most DVDs have a certain level
of redundancy in dimples, so some scratches don't inhibit play. When a disc
is 'sanded' by one of these repair units, the polycarbonate layer gets
thinner - some units don't sand the layer level and it becomes 'cupped'.
The Venmill unit actually fills in scratches with an adhesive and buffs the
layer, but when long or deep scratches get filled in the filler substance
still affects the laser refraction (look what happens when a longer
scratch/rock chip is filled in on your car windshield - you get a rainbow
effect). While personally, I think that the RTI machines work the best and
are the most cost-effective (supplies-wise)(having not tried the Venmill or
similar units), whatever unit one uses, I think that the patron comment form
is the way to go for inspection - especially after the first
cleaning/repair. Jim Scholtz.

-----Original Message-----
From: owner-videolib@lists.berkeley.edu
[mailto:owner-videolib@lists.berkeley.edu] On Behalf Of Trish Klein
Sent: Monday, June 25, 2007 5:46 PM
To: videolib@lists.berkeley.edu; publib@webjunction.org
Subject: [Videolib] Disc Repair Procedures

Hi, please forgive the cross posting. I'm not sure if I have seen this
topic before, so please feel free to direct me to archives if need be. I
would like to know how other libraries deal with their disc repairs. We
currently have two disc repair machines, DiscoTechDisc-Go-Devil and the
VMI 3500. When a customer complains about a disc, a package needs
replacing, or a barcode is missing, the disc is sent to our technical
services assistant. She checks them, cleans them (2 - 16 minutes per
disc) and if there are still scratches, is supposed to watch them to see
if they are working or not (2 min. - 2 hours). Her feeling is that
watching them is a waste of time and that any scratches left on the disc
after being repaired means that they are not viewable any longer.
Needless to say, there is some disagreement about the procedures as many
of us feel that good discs that just went down for repackaging are being
consigned to the garbage. What are your procedures? Any suggestions?
Thanks, Trish

Trish Klein
pklein@rdpl.org
Readers' Services Coordinator
Red Deer Public Library
4818-49 St. Red Deer, AB T4N 1T9
403-342-9110 Fax: 403-341-3110

VIDEOLIB is intended to encourage the broad and lively discussion of issues
relating to the selection, evaluation, acquisition,bibliographic control,
preservation, and use of current and evolving video formats in libraries and
related institutions. It is hoped that the list will serve as an effective
working tool for video librarians, as well as a channel of communication
between libraries,educational institutions, and video producers and
distributors.

VIDEOLIB is intended to encourage the broad and lively discussion of issues relating to the selection, evaluation, acquisition,bibliographic control, preservation, and use of current and evolving video formats in libraries and related institutions. It is hoped that the list will serve as an effective working tool for video librarians, as well as a channel of communication between libraries,educational institutions, and video producers and distributors.