Here is a revised edition of my dark/bright SaLaTa:
Let the names be the same as before, but let Ro come out as
either dRo (Ebb) or bRo (D).
(This way, it puts the Pythagorean C closer to ET.)
Steps represent semitones as before; but at a finer level you
would measure intervals as a combination of dark and bright
steps. A dark step = m2, and a bright step = +1.
So, at the abstract level one could say that there are seven
steps between Do and Sa (there's a perfect fifth from C to
G). At the finer level one would say that there are four dark
and three bright steps between dark Do and dark Sa.
It doesn't actually matter in what order you take those steps
(it's akin to how you add vectors in mathematics).
If you like to verify this, look at the (RH) keyboard I propose
and try any combination of four dark steps (m2 = diagonally
down) and three bright steps (+1 = diagonally up), and you
should always land on the perfect fifth:
http://nydana.se/keyboard.pdfBut what should we call a note such as Cx, for instance?
I suggest xbRo, where x means extra; so, it's an extra bright
Ro. If you want to go even further out on the spiral, you just
add another x, for example: xxbRo, the extra extra bright Ro
(B###).
So, now you can name all notes and describe intervals - at
two different levels of abstraction.
Let me just say that you don't necessarily have to color the
noteheads black or white, it could suffice to use the "window
frames" I've talked about previously (simply apply the new
note names).
The black/white distinction could alternatively be expressed
in some other form - such as letting triangles have rounded
or sharp corners, or changing the slope of oval noteheads,
and so on.
Ideally, the black and white should be differentiated into a
grey scale (but that may not be convenient if you want a
thoroughly black/white notation). What you would see then,
is, for example, the C major scale with C as dark grey, D as
grey, E as a lighter shade of grey, F as a slightly darker
shade than C, and then increasingly brighter shades for
G, A and B. The whole sequence of perfect fifths would go
from very black to very white.
Then, when you play the piano, you may notice that the
brighter the color of a notehead, the more emphasis you
will generally give to that note.
Dan