Sam DiCamillo wrote a very interesting response to Jeremy and Jessica’s post (see comments). He sees chromaticism as a way of adding ‘color’ which is what the word connotes and in classical music chromatic (non-chordal) tones are often used for that purpose. He then says:
“Bach created some of his great masterpieces almost completely devoid of “chromatics” and others such as his “Chromatic fantasy” were brimming with color tones, and who is to say which were more “Mature”.
Some of Chet’s ( Baker ) solos, in the same vein, are almost void of chromatics, and others are full of them.”
I’m not sure it is maturity as much as the use of musical resources. Bach modulates a great deal, with within each key remains diatonic and certainly there is no reason to want more musical interest than Bach (or for that matter Mozart) offers. But by the time you get to Beethoven things start to look rather different.
My sense is that Charlie Parker’s innovations (extensions of the dominant 7 chord as I discuss in my response to Jessica) is adding the harmonic richness of the romantic composers (which lets you play 11 notes against a dominant chord- every note except the major 7th). Coltrane’s use of whole tone divisions of the octave (Giant Step changes) moves jazz improvisation into the impressionist composers of the first half of the 20th century (permitting all 12 notes to be played, but in a patterned way). Post-Coltrane musicians, for example, Erik Dolphy and Cecil Taylor move chromaticism into the realm of later 20th century music with true poly-tonality and the free juxtaposition all 12 notes against any chord.
This is more than adding color, it is forcing the improvisor to develop sequences that have integrity even when they are not supported by the chords (Coltrane was working with sequences throughout his later recoding).
Naturally you can make music with any of these approached. Louis Armstrong made great music with only blues colors added to a basically diatonic vocabulary.
Please keep the comments coming. Thank you Sam for your provocative post.