Marking CD-ROMs

John A Olson <j-olso [at] vm1__spcs__umn__edu> writes

>... are getting more and more CD-Rom disks added to their collections. I
>would like to know from anyone on how they, or if they, write any
>cataloging ID or call number on the actual disk? There is discussion
>that writing anything on the disk anywhere will make the disk unbalanced
>when used and that writing with a permanent pen or marker might bleed
>into the disk over time.

There are several different types of disks that are generally called
CD-ROM's, including:

    CD-DA
    CD-ROM
    CD-ROM XA
    CD-R
    PHOTO CD
    CDI
    Laserdisks

and others.

It is very important to pay attention to the manufacturers
recommendations for these different media types.  Although CD-Rom's may
look the same, the physical construction may be very different due to
the capabilities of the system.  For example, recordable CD's (there are
several kinds) have a composition that will allow data to be recorded on
the disk, and therefore are generally more fragile than the typical
music play only versions mastered in large plants.  These different
media have different layers and composition, so that it is possible to
use a chemical that could over time damage a protective layer.

Most "commercial" CD's that are duplicated in a large facility have  a
very thin layer of varnish that separates the aluminum disk from the
printing on the top of the disk.  The duplicating industry has had
considerable discussion lately on the types of inks used in production
(it seems that some inks can cause problems over time).  In general, one
should never use a ball point pen or any writing implement that will
cause any physical pressure to be placed on the disk.  A felt tip marker
should be used, and in the case of recordable cd's write only in the
area designated for the writing.  I would not be too concerned about
"unbalancing" the disk, but your other concerns are well founded.

Jim Lindner
VidiPax
The Videotape Restoration Company

                                  ***
                  Conservation DistList Instance 8:27
                Distributed: Saturday, October 15, 1994
                        Message Id: cdl-8-27-002
                                  ***