Sunshine and Shade (Todd Harrop, 2020)

Sunshine and Shade (Todd Harrop, 2020), for solo electric guitar, was written in Gary Morrison’s 88-cent scale on a 41tone instrument, viz. every third fret of the 82-fret Lucid Movinguitar. Since the scale neatly divides the perfect fifth into 8 equal steps my next incentive came from Iacobus de Ispania (d. after 1330), who is reported to have classified the 9/4 major ninth as a concord, and I composed as if using a scale of 16 chromatic steps per doubly-augmented octave. In each of the two movements only nine pitch classes are used, such that key transpositions at the perfect fifth would be most harmonically distant and transpositions at the diminished fifth would be least distant, in contrast to our conventional diatonic scale system. Dedicated to Victoria Harrop.