The piano roll note colors grow fainter depending on certain things:  If I select a track by clicking in the piano roll or elsewhere (NOT selecting the notes in the track), the notes are very dark.  Notes from other tracks that are also currently in the piano roll are much fainter.  Additionally, if I lock a track, the note colors get very faint to the point of not seeing much.  They also vary, of course, based on velocity, but even at max velocity, the non-selected track's notes are much fainter than the selected track's. 
 
I can use the preferences menu to darken the notes in a track, which darkens the notes of both selected and non-selected track's notes.  But in order to get good visibility on the non-selected track's notes, I have to make the selected track's notes very dark.  Is there a way to change how much fainter (or "brighter"?) the notes get when they are in non-selected tracks or even when locked?

I don't think you can control the degree of dimming of unselected notes, but you can disable the velocity colorization so that they all show as if they are velocity 127.
 
Set PRVColorizeVelocity=0 in Cakewalk.ini (Preferences > File > Initialization File)

Ok, thanks, that may help some. It's a pain to try to edit/add notes on one track when I need another and I can barely see the notes of other tracks.
 
One solution I have used to see two tracks against each other is to select a track in the piano roll then select all the notes of another track (say by selecting the track in the track view list), but that of course fails as soon as I start to edit any notes.
 
It would be particularly nice to be able to see locked notes sometimes so that I could use those notes to help me edit or add notes to a different track without accidentally changing the track with the locked notes.  That looks like a completely separate color (a light gray).  Do you/anyone know the setting for changing the color of locked notes?
 
I guess I could also play around with the background (changing the background to dark and then making the base note colors very light?).