I've been doing some reading up on this: Rex Lawson wrote an article
in issue 1 (1987) of "The Pianola Bulletin" and also wrote program
notes for a CD recording of the Pleyel rolls.

Firstly, the four-roll set of Rite of Spring referred to by David
Sharpe appears not to be Stravinsky's Pleyel product but the 1921
Themodist issue by Aeolian in London (T24150 - T24153), taken from
the published 4-hand arrangement.  Gordon Iles, under his Artona label,
recut a wide variety of music from the late 1950 to the early 1980s,
but the quality of the copying or the production isn't really up to
modern standards.

The Pleyel set runs to 9 rolls, and Stravinsky most emphatically did
not intend it as a 'four-hand' [piano duet] version.  He was, by that
time, interested in creating works where human fingering considerations
were irrelevant.  He also wanted to produce versions of his works that
would perform as he felt they should be, without excessive liberties
being taken by artists.

Consider that early orchestral performances were very poor, because the
musicians simply had no experience of playing this sort of music (even
when Stravinsky conducted).  You can understand Stravinsky's interest
in a player piano that simply did what it was programmed to do.  He
almost certainly had no idea of the lengths to which a determined
pianolist can interpret a roll.

Rex describes how the Pleyel rolls were created under Stravinsky's
direction by Pleyel's roll division under Jacques Larmanjat.
Stravinsky's direct musical input, other than the notes themselves,
was the number of perforations per beat, which governs the tempo of
the various passages when the roll is played at a fixed paper speed.

This is how the rolls were designed to play, and as such represent
Stravinsky's intention about how the music should sound "in order
to create a lasting document which should be of service to those
executants who would rather know and follow my intentions rather than
stray to irresponsible interpretations of my musical text."

Dynamics are indicated as printed markings on the roll, and (whatever
Stravinsky thought) present a serious interpretational challenge to the
Pianolist.

As to the actual manufacture of the rolls, having looked at my
handful of l'EMP and Pleyela rolls, I have to say that they are utterly
different in every respect, and quite clearly not the same maker!  The
sample is small; it is always possible that some rolls were brought in
for whatever reason.

Rex Lawson has recorded the Pleyel rolls of "The Rite of Spring" on
several occasions, I believe.  I have his 1990 CD which pairs the roll
version with an orchestral version, but it's not in current listings.
Look out for any of the recordings, because Rex manages to get to grips
with these compositions in a way few others could.

Rex's more recent recording, "The Virtuoso Pianolist", includes the
Pleyel version of "Les Noces", and can be purchased directly from the
Pianola Institute in the UK for UKP 10 plus extra postage if outside
Europe.  See their web site http://www.pianola.org/ for musical and
ordering details.  (Amazon.com claim to have 5 copies in stock).

This CD also has various of Rex's own roll arrangements, and is
strongly recommended.  Rex's 4-roll set of "Pineapple Poll", based on
Arthur Sullivan's music from the Gilbert & Sullivan operettas, is quite
delightful and a world away from the heaviness of the Stravinsky.  The
rolls ought to have been a best-seller (and one day might be), but
that's another story.

Julian Dyer