The photographer of jazz whose work is art in itself is Roy DeCarava. His book “The Sound I Saw”—a montage of his images and texts that he composed in the early nineteen-sixties but was unpublished until 2001—reaches deep to the experience, of the black American city life, that the music embodies and the musicians express. (It’s newly reissued, and DeCarava’s work is also the subject of a pair of current exhibits at David Zwirner.) DeCarava’s musical portraiture is centered on the public performance of jazz in clubs and in concerts. Yet there’s another crucial aspect of jazz history—the private side, of music made in recording studios—which is documented in a remarkable archive newly available online: the photographs of Francis Wolff, which preserve precious moments of some of the greatest musicians at work on some of the most enduring jazz recordings.

Wolff’s photos are a peculiar, passionate, and personal subset of the medium: they’re both documentary and promotional, made in part for use on album covers for the great Blue Note record label, of which Wolff was a co-founder, along with Alfred Lion. They were childhood friends in Berlin, Jews who escaped Nazi Germany. The pair founded the label eight decades ago, and ran it together until 1966. Together they fostered a collective body of work and a teeming set of individual performances that are at the center of modern jazz history and a core of the music’s living repertory; Wolff’s images offer keen reminiscences of historic musical moments, and they inspire fantasies about what it would have been like to experience them in person.

Jimmy Heath, Percy Heath, Miles Davis, and Gil Coggins at a rehearsal for the “Miles Davis All Stars” ’ second session, New York City, April, 1953.

Despite their practical function, Wolff’s photos go far beyond the promotional; they are a part of the Blue Note label’s authentic devotion to the artists. In recording and promoting jazz, Lion and Wolff called attention to black American artistic heroes—many of whom they brought from merely local renown to the enduring spotlight—and Wolff’s photographs reflect the depth of his admiration for them, artistically and personally. (It’s exemplified in his habit of photographing artists from low angles—he’s literally looking up at them.) If there’s an element of mythology in the images, it’s one that’s rooted in truth—in the authentic artistic power of musicians who may have been at the margins of mainstream media but who, for Wolff and Lion, deserved the canonization of any of the cultural celebrities of the time.