How do you harmonize scales like
- C C# F F# Bb
- Whole tone scale : C D E F# Ab Bb
?
(The scales above are just examples.)
Scales like these do not seem to bias to Major or Minor harmony, right?
What chords do you use/hear when these kind of scales are used?
The whole tone scale is generally associated with the augmented chord (+5 triad or +7 or 7#5, in the jazz notation).
Your first "scale" is not really a scale. C7sus4 b9 #11 matches, but so do does Bb -7 9 b13 / C
You'll get a large set of examples in the Scale Syllabus (http://www.jazzbooks.com/mm5/download/FREE-scale-syllabus.pdf).
A short simple answer could be the same as for any scale: You use the notes of the scale to assemble chords!
This is at least what you do in jazz;
Say, for example, that you have a jazz melody that (for the passage you are harmonizing) uses the notes of a C mixolydian b9 b13 scale (C Db E F G Ab Bb). Then you can use chords built on the notes of that scale such as for instance C7(b9b13) or Bbm9, but you can't harmonize with for instance chords as C6/9 or Bb△7 since these chords contain notes that are not in the scale that is used in the melody.
But I believe more data is needed from the question. Are the scale notes the only ones allowed or available, or are actually other notes available to use for the chords? -- For example: Harmonizing with only the five notes of a pentatonic scale will give you a very different result than when you use a pentatonic scale in a jazz blues context where you actually have other notes available for harmonizing (and thus the scale, in some sense, is actually not only a pentatonic).
I recomend that you read Vince Persichetti's Twentieth-Century Harmony: Creative Aspects and Practice. The basic idea is that you want to highlight the distinguishing characteristics of a scale when harmonizing it — but the book is an easy and worth-while read.
Like asking how to harmonize a major or minor scale, there answer is endlessly nuanced and flexible. A quick list of rules wouldn't do justice to the whole-tone scale, let alone every possible scale. The best way to get an inner sense of what works is by reading an introduction like Persichetti's and then trying different things (and reading scores to see what others have tried).
