Duke Ellington liked to recruit players to fill the roles his departed musicians had created. Hence, Cootie Williams 'became' Bubber Miley in a way, while numerous trombonists gave their own impressions of Joe 'Tricky Sam' Nanton.
One of these substitutions that is rarely mentioned is where Barney Bigard and Russell Procope are concerned. Procope was New York-born, yet he obviously admired New Orleans clarinetists. His early recordings, notably with Jelly Roll Morton and Fletcher Henderson bear this out.
Barney Bigard, one of the stars of Ellington's 'Golden Age', left the band to freelance in 1942. His chair was not directly taken by Procope, but when Procope did join, Ellington used him in a similar way - when the music called for a warm and earthy, New Orleans-style clarinet solo, Procope was it. Jimmy Hamilton, the other clarinet specialist in the group, had a polished and somewhat emotionally-detached approach, and you can usually tell the difference by their use of vibrato; Procope's vibrato was fast and obvious, while Hamilton played with almost none.
Follow the link below to see Russell Procope play an emotive clarinet solo on Mood Indigo. Also of interest is Harry Carney playing bass clarinet in the opening trio.