Live blues seems rather common in South Florida clubs. Blues on the radio is another story. Jazz DJs such as WDNA's Frank Consola, WLRN's Len Pace, and WTMI's China Valles occasionally spin the blues, but full shows are sparse. WDNA's weekly program Portraits in Blue is a bright star in a dark sky. Portraits (Monday from 11:00 a.m. to noon) devotes its entire hour to a single artist's music. Brief, often poignant, biographical information about the artist also is included throughout a set of tunes spanning the musician's career. Informative and entertaining, Portraits is produced in New Jersey. Too bad. Let's hope more local radio programmers take note and follow suit with shows of their own.