As long as I am on the subject of finishing, I have two other little
tidbits to share:

1.  I recently found out the history of "Fumed Oak".  It was at the
back of a WW1-era book on furniture by the renowned Gustave Stickley.
He explains that a farmer noticed that some raw oak planks he kept
in a barn had turned a beautiful shade of brown.  After enough
investigation, it was discovered that what was happening was that
ammonia fumes were reacting with the tannic acid in the oak.  (The
ammonia was there because of the farm animal's waste products!)

The most important part was Mr. Stickley's revelation that, although
the fuming technique darkens the wood, it does not darken the unique
light areas found in oak.  The reason oak is quarter-sawn is to
emphasize these beautiful areas (called "ray fleck").  This apparently
means that any attempt to stain or dye oak will lessen the contrast
between the dark and light areas, and therefore tend to mask the
beautiful pattern, while fuming will tend to increase the contrast
and beauty.

2.  A wood that is usually called "African Mottled Mahogany" (although
it seems to be called a number of names) was quite popular from the
turn of the century to the 'twenties.  It seems this wood was invariably
given a deep red stain, and if you have ever seen an original finish in
good condition, you would remember it.  The wood has a shimmering,
iridescent quality; it reminds me of those 3D holograms that were
invented years later.  One thing I like to point out to people is that
if they place a finger on a dark area, and then move their heads to get
the light to reflect a different way, their finger is now on a light
area (and vice-versa)!

In any case, I read that a chemical called potassium dichromate has
unique properties on mahogany: it gives it a beautiful deep red color.
It is my understanding that it does not do this with other woods.  For
people attempting to recreate this type of finish, potassium dichromate
is an important piece of the puzzle.  Incidentally, I have heard that
this chemical is not particularly dangerous, or expensive.

It is sad to see refinished pianos or other furniture made of this
mahogany.  Although the grain pattern is unmistakable, the wood has a
flat, dull and lifeless appearance compared to how it used to look.  It
seems that both refinishers and the public don't know or care.  I have
heard that the chemical differences between shellac and lacquer
contribute to this loss as well.

Randolph Herr