Welcome though Mozart’s Piano Concerto No. 20 in D minor always is, it is not exactly a seldom performed work. Combined with Modest Musorgsky’s best-seller Pictures at an Exhibition for the Israel Philharmonic Orchestra’s matinee concert last week, the result was a rather conventional program.Pianist Arieh Vardi’s sensitive performance, however, was generous compensation. As the mature musician that he is, he started with a moderate allegro tempo, not letting himself be trapped into the current trend among (some) younger superstar pianists toward sportsmanlike velocity. Vardi savored every note with loving care, investing each with its full value and not letting any be swallowed. As a result, he persuasively conveyed the work’s tragic, somber mood. Contributing new cadenzas of his own, the pianist also offered some refreshing variety.In the slow movement, he virtually made the piano sing, reminding one that Mozart was also a composer of operas and lieder. In the final movement, he respected the restraining caption on the Allegro (“fairly fast”), emphasizing its playfulness without storming ahead.Why Ravel’s admittedly ingenious orchestration of the Pictures should be preferred to Musorgsky’s own piano version or to an original orchestral work is an unanswered question, especially as there is no shortage of those, even by Ravel himself.Conductor David Robertson’s rendition was nevertheless immensely impressive. The orchestra sounded uncommonly transparent despite the work’s heavy orchestration, the abundant instrumental tone colors were attentively highlighted and many oft-neglected but significant details were carefully revealed.The Russian pomp and circumstance of the (non-existent) Great Gate of Kiev forcefully and inescapably sent the audience to its well-deserved lunch at the conclusion of the concert.