Here we dicsuss 2 simple methods of how at the melody in a diatonic scale we may enhance it from the 7 notes of the diatonic scale to the 12 notes of the chromatic scale (This is called full chromatic tonality see post 263) which is a usual nice feeling of completness.
A) The first method is to conceive the full pentatonic scale of the chromatic or blue notes 5b 6b 7b 2b 3b and utilize its two main chords 5b major (=5b-7b-2b) and 5bsus2 (=5b-6b-2b)as chromatic transition 4M 5bM 5M and 4M 5bsus2 5M then the 3b minor (=3b-5b-7b) as chromatic transition 2m 2bm 3m . This will give all the 5 blue or chromatic notes of the 7-notes of the diatonic scale
B) The 2nd method is to involve the transition ofthe involved natural minor to harmonic minor and double harmonic minor and thus convert the chords 2m 3m , 6m , 7d to 2M, 3M7, 6M7 and 7M7 which again will give all the 5 blue notes 5b 6b 7b 2b 3b
All the above techniques are very common in harmonies and melodies of Gypsy Jazz , Latin Jazz, traditional Brazilian music etc.
A) The first method is to conceive the full pentatonic scale of the chromatic or blue notes 5b 6b 7b 2b 3b and utilize its two main chords 5b major (=5b-7b-2b) and 5bsus2 (=5b-6b-2b)as chromatic transition 4M 5bM 5M and 4M 5bsus2 5M then the 3b minor (=3b-5b-7b) as chromatic transition 2m 2bm 3m . This will give all the 5 blue or chromatic notes of the 7-notes of the diatonic scale
B) The 2nd method is to involve the transition ofthe involved natural minor to harmonic minor and double harmonic minor and thus convert the chords 2m 3m , 6m , 7d to 2M, 3M7, 6M7 and 7M7 which again will give all the 5 blue notes 5b 6b 7b 2b 3b
E.g. A characteristoc example is a well known tarditional song Brazilian song in G major with the arc of chords F#7-B7-Em-Am-D7-G7-C , or in the G major diatonic 7M7-3M7-6m-2m-5M7-1M7-4M where in the refrain from the more sad to more happy part of the song, the Em (6m) becomes E7 (6M7) and the Am (2m) becomes A (2M) . When from the sad part of the song (3M7-6m-2m) it goes to the happy part with triad of majors 1M7-4M-5M7 , the song it falls the 4M to 4m (to do so the common pair of relative chords 2m-4M is inverted to 2M-4m) which also gives it the chance to translate to 3m (which so far it was 3M7) and thus all 12 chords 7M7-3m7-6m-2m-5M7-1M7-4M and 7M7-3M7-6M-2M-5M7-1M7-4m occur in the song which also gives all 12 notes in the melody when starting with only the 7 notes.
All the above techniques are very common in harmonies and melodies of Gypsy Jazz , Latin Jazz, traditional Brazilian music etc.