I just listened to a 36-year-old tape of a lecture/demonstration (which
I had attended) of the Welte Reproducing Piano System, given at the
University of Southern California (USC) by its Professor of Piano,
Dr. John Crown, assisted by my father, Richard Simonton.  While still
far from the definitive description of the recording/reproducing
process, some valuable clues were presented.

In describing the recording, my father again told of the carbon rods
and trough of mercury.  Then he mentioned "colloidal graphite" in the
ink used to mark the master roll.  The word colloidal obviously
appealed to him and he seemed to enjoy saying it.  I interpret the term
to mean very fine particles.  Elsewhere in the talk, he emphasized that
the ink was electrically conductive.  All of this reinforces the notion
that master rolls could be played back before being perforated.

My father also once more mentioned a translating machine, but this
might be misleading, as it could have referred only to the duplicating
process.  I believe that somehow the ink marks on the master rolls --
after the performing artist's approval had been obtained -- were then
perforated by hand or by a special machine, and that the masters that
I remember were the original rolls of paper to which the ink had been
applied during the recording.

No doubt, many others have a far better knowledge of this process, and
I missed my chance to be a leading authority.  While growing up, I took
it all for granted, but was nevertheless thrilled by the music.

The tape of the lecture was transferred to DAT this morning and will be
on CD before the end of the day.  Anyone who would like a copy may
contact me by e-mail.

Richard Simonton, Jr.