Porgy’ leitmotif containing an upward grace note symbolising his stumbling and clumsiness as he is a cripple also features chromatic chords, reminiscent of his small steps, and a perfect fifth followed by a minor third that shows the solidity and folk-like nature he shares with Catfish Row. Crown’s leitmotif is strong and energetic with continuous syncopation, and is confined within a minor third; keeping with his dominant presence, when Crown appears, or is alluded to, all other music is subordinate.
Integration also features in, ‘Girl, Crazy’ in the number ‘Bidin’ My Time’. This male quartet sings downward glissando on the words, ‘Time’ and ‘I’m’ to represent a yawn or a sigh. The style of this piece is relaxed and legato to symbolise the slow passing of time.
In their later productions, the Gershwin brothers started to deal with more controversial issues such as war in ‘Strike up the Band’ 1930, and racism, drugs, and murder in ‘Porgy and Bess’. The separation of race in ‘Porgy and Bess’ in evident during the funeral scene when two white policemen interrupt and speak instead of using recitative or song like the black occupants of Catfish Row do.
The influence of jazz and black American music is obvious in both ‘Porgy and Bess’ and ‘Girl, Crazy’ through the use of blues notes. During the opening scene of ‘Porgy and Bess’, an on-stage pianist is playing a slow blues, and the use of the 16 bar blues chord sequence and descending minor third in ‘Summertime’ are also characteristic of this style of music as is the swing rhythm and portamento in the number. The harmonic style and use of alto voice with rit in ‘I Got Rhythm’ from ‘Girl, Crazy’ is strongly influenced by late 1920’s jazz and is in an upbeat swing and Charleston dance style.
Some of the music within ‘Porgy and Bess’ has also been influenced by stylised spirituals as in ‘Oh, Doctor Jesus’ there is a six-part vocal texture referencing to the Pentecostal Church via the use of pentatonic melodies. Romantic idiom is also employed within this opera as ‘Summertime’ is accompanied by lush strings and rich chromatic harmonies which includes augmented triads, added 6ths,7ths, 9ths, 13ths chords to depict the mother’s love and experience.
Influence of popular song styles of the time is also strong within ‘Girl, Crazy’; the chorus in ‘I Got Rhythm’ is structured in the popular 32-bar structure and ‘Embraceable You’ is set in rondo form; ABAC, also a popular song structure in the 1930s.
The Gershwin brothers made a huge contribution to the music from the Broadway musical era both through Ira Gershwin’s sophisticated lyrics and George Gershwin’s musical stylings.