Hi All,  The following remarks have no basis in fact and are purely
conjecture on my part based on my twenty-five years in the trade.

It's true that the vast majority of piano finishes in the 20's were
fairly dark.  This 'appearance' is compounded by the fact that varnish
finishes darken with age.  The reason they darken has to do with the
fact that as the finish 'shrinks' (as it fully dries), it cracks.
These cracks, which start out as microscopic cracks, refract the light
instead of reflecting the light.  This causes the light to move in
numerous directions and therefore causes the finish to 'appear' almost
black.

Another reason for dark finishes has to do with period furniture.
Darker furniture was in vogue in the 20's.  Why? It's only conjecture
on my part but I think it had to do with two things.  One, dark
furniture looks more elegant, more majestic and it appears 'bigger'
than it really is.  (I'm no authority but I believe this is one of the
reasons that larger women prefer wearing lighter clothing).

Secondly, and probably less important, it is easier to make the
instrument 'appear' very uniform in color if it's shaded darker.  The
finishes were actually very rich and deep but all piano refinishers
know that since the piano is made up of various types of wood, it's
fairly difficult to make them all look the same color.

This is slightly more true in player pianos than it is in regular
pianos because of the 'flip board' and the sliding doors which both
usually had 'some other wood' showing.  This is also true of most piano
legs which were not always veneered.  So it was simply easier and more
cost effective to make the finish darker verses natural color.

Based on experiences in my own life, I noticed a shift to lighter
colored furniture in the 50's when Danish Modern was in vogue but my
folks still had the dark-red mahogany hi-fi cabinet and dining room
set.  In the 60's, Aeolian started making blonde cabinets for most of
their players because it was in vogue.

So my main point is that manufacturers usually try to follow the tastes
of their customers.  And although I only have one or two examples to
back this up, I've been told by customers who own very lightly colored
pieces from the 20's that the pieces were custom made as opposed to
commercially available.

Musically,
John A. Tuttle
http://www.playercare.com