When the traditionalists among us think about organ music, German Baroque masters like Buxtehude and Bach come to mind first, followed quickly by late-19th- and 20th-century French composer-players like Vierne, Widor and Messiaen. But as the Friends of the Kotzschmar Organ remind us, once or twice a year, an important current in the instrument’s modern history is the instrument’s association with film, forged in that medium’s early, silent years.

Even before films had dialogue and scoring, filmmakers and theater owners understood that music, with its ability to telegraph emotional cues, is an essential element in a film’s hold on viewers’ attention and imagination. So early film houses, depending on their circumstances, hired orchestras, chamber groups and pianists, or had an organ installed, often with special sound effect stops that, while unneeded for Bach recitals, are useful in film accompaniments.

As part of its celebration of this corner of organ history, the Friends organization has established a Halloween tradition of presenting a silent horror classic, with an organist providing live music, preceded by a costume competition open to children of all ages.

This year’s installment was the 1920 version of “Dr. Jekyll and Mr. Hyde,” directed by John S. Robertson and starring John Barrymore, to which the young, Boston-based organist (and organ builder) Jonathan Ortloff provided a wonderfully effective score.

Because the film is relatively short, at just under 80 minutes, Ortloff played the first movement of Félix-Alexandre Guilmant‘s Sonata No. 1 (Op. 42) as an overture. Guilmant’s grand, symphonic piece proved weightier and more harmonically complex than Ortloff’s score for the film, but that hardly mattered. The sonata’s dissonant opening chords created a sense of tension and tragedy – qualities that, in a Halloween context, inevitably read as “scary,” but which also perfectly suit the spirit of the film, an exploration of human duality (good and evil), based on Robert Louis Stevenson’s 1886 novella.

Organ scores for films are often improvised, and Ortloff’s may have started that way, many performances or rehearsals ago. But on Saturday, he put a notebook with ideas on the organ’s music stand, and played a score that sounded thoroughly composed.

A high trill, a steady pedal tone and a descending melodic riff accompany our first glimpse of Jekyll, but when we see him at work, peering at micro-organisms through his microscope, the accompaniment grows brighter, almost march-like.

Playful music introduces the home of Sir George Carew, who challenges the doctor to get in touch with his more licentious side, and his daughter, Millicent, to whom Jekyll is engaged. And Gina, the exotic dancer who briefly takes up with Hyde, the embodiment of Jekyll’s dark side, is introduced with an Italianate dance.

Jekyll’s transformation into Edward Hyde, his evil self, is one of this film’s signature moments, accomplished (at first) through Barrymore’s makeup-free facial contortions. Ortloff’s accompaniment was ominous and dissonant, but not so violent as to wrest attention from the scene.

Ortloff gave an assured, graceful performance of his imaginative, rich-hued score, which proved an enlivening contribution to the nearly century-old film. He also offered a brief introduction, in which he noted the extreme acting conventions of silent film, as well as the details of Barrymore’s transformation from Jekyll to Hyde.

One thing he did not mention, curiously, was that although “Dr. Jekyll and Mr. Hyde” does not have a soundtrack, it does have a composer: Edgard Varèse, the French avant-gardist and electronic music pioneer, makes an uncredited cameo as a London policeman. At the time the film was made, Varèse was working on the spectacular orchestral score “Amériques.”

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at:

allankozinn@gmail.com

Twitter: kozinn