[ Forwarded by Robbie Rhodes:

Hi, Jack.

Robbie Rhodes sent me your recent notes regarding scanning music box
disks, and it piqued my interest.  I have a few suggestions that might
be helpful.

First, however, I hope you can clear up a point for me about
nomenclature.  I know that historically we have used both the spelling
"disc" and "disk" in English.  I believe that both spellings have been
accepted as correct for some hundress of years, but that in the very
recent past (since about 1980) there has been a division along
functional lines.  The spelling "disc" seems to be used generally,
where no specificity is wanted or needed, but "disk" seems to be
preferred when referring to items in a a computer.  Thus,. we have the
"Compact Disc" digital audio system and "disc" brakes, but a home
computer user will say that his "hard disk" has a capacity of so-and-so
many megabytes.  Floppy disks are really "diskettes" and therefore have
only one spelling.  Do music boxes use "discs" or "disks" and why?

Your suggestion to scan music box disks strikes me as being timely and
valuable.  The technology to do such a thing is with us; this was not
the case as recently as ten years ago.  There is not the urgency
connected with this effort that there is with music rolls, which are
becoming increasingly fragile with each passing year.  Nevertheless, it
seems to me that scanning music box disks is worth while.

Robbie Rhodes has suggested an experiment to explore the problem.  His
idea is to photocopy a small, relatively coarse music box disks and
scan it, and then do the translation as required.  This is an excellent
approach, but I think too small a step.  It would be better, it seems
to me, to take a larger first bite out of the problem.

I suggest that you select a disk of particular interest.  This should
be a disk for which there is or could be a widespread interest because
of its scarcity or musical value.  I suggest that you go to the trouble
of making a high-quality photograph of the disk using a flat-field lens
(intended for copying photographs) fitted to a 35 mm camera.  I imagine
that the disk would be mounted horizontally with the tangs down, and
uniformly illuminated from below, to provide high contrast.  A white
bed sheet lit by 3 or 4 desk lamps would provide a suitably diffuse
surface.  The camera would be mounted on a tripod, looking straight
down at the disk.  After developing the film, the 35 mm negative would
be scanned with very high precision by an optical shop that provides
such a service.  Robbie could operate on the resulting disk file and
prepare it for other use.  I do not see any fundamental reason why you
could not use this technique to scan any number of disks at relatively
low cost, and without the effort required to develop a special
scanner.

The only problem that I can imagine is resolution.  We would like about
10 to 20 pixels per channel.  If a disk contains 200 channels (100 on
either side of center), we would like 2000 to 4000 optical lines of
resolution.  High-quality lenses and film are good for about 100
optical lines per millimeter; this may not be sufficient when using 35
mm film.  A larger format camera may be required.

I hope this note is of value.  I wish you the best of luck in your
efforts.

Sincerely Yours,

Wayne Stahnke.

 [ Editor's note:
 [
 [ It would be interesting to know if the Kodak "Photo-CD" format
 [ preserves enough resolution from 35mm film for this purpose.
 [ Its relatively easy to get an entire roll of film converted.
 [ The CD would probably have to be shipped to the interested
 [ party, as it quickly becomes a lot of data.
 [
 [ Jody