Responding to Patrick Boeckstijns' question about accompaniment rolls
-- there were a surprising amount of these rolls in the early days of
the player piano. Quite a number of these were for operatic vocal
work, but there were all sorts of other instrumental accompaniment
I've been working through the 1914 UK Themodist catalogue and it's
fascinating what's in it: there are complete sets of rolls from operas.
The early musical Puritanism that produced many of these rolls may
have abated somewhat by the advent of the reproducing piano, but the
reproducing catalogues still have quite a good selection (although how
many are operatic I don't know).
Generally speaking, it's better for a live pianolist to act as
accompanist so that the performance can be altered to suit the needs
of the singer, rather than the singer needing to adapt themselves to
the original performance. It's challenging but great fun to attempt
this sort of thing!
The Aeolian Company's term of art for a song roll without the words
printed on it was 'Song arranged as a piano solo'. These are common
in the Themodist catalogue and can be used for vocal accompaniment
(the same masters were sometimes used to produce song rolls as well).
The approach among those musicians in the UK who use them seems to be
that the prominent melody notes, used to keep amateur singers on tune,
should be taped over for more accomplished singers, giving a piano
performance more like a professional accompaniment.