A literal combination of the Russian words "x-ray" (roentgen) and "self-publish" (samizdat), Roentgenizdat records were born out of underground cultural and political necessity. During the 1950s, while the western world was vibrating with a collective surge of intense music discovery (hello, rock and roll) the iron curtain over the Soviet Union prevented any of these sounds from legally entering the USSR. Vinyl, the medium of the day for pressing records, was nearly impossible to source economically, so records that did manage safe smuggling passage into the hands of hungry music lovers could not be easily copied and shared. The ingenius solution to this challenge came in the form of a plastic that was both common, and cheap (if not completely free via dumpster salvage): x-ray film.
There is no single individual credited with the innovation, and word is not 100% clear on exactly how it was done, but some intrepid and enterprising collective supposedly put to use converted phonographs to "press" records into the discarded films - dubbing contrabanned sounds right over the gostly images of human anatomy. Roentgenizdat recordings were predictably less robust than their vinyl parent records, and the thinner plastic made the records tempermental to play, and much shorter lived, but they cost a fraction of the price of vinyl records, and they enabled the sounds of Little Richard, Elvis Presley, John Coltrane, and Thelonious Monk, among so may others, to be heard by millions.
Roentgenizdat records were distributed through the blackmarket until an official Soviet government "Music Patrol" clamped down, eventually breaking up the largest distribution ring in 1959, and sending all of the leaders to prison. Even the KGB couldn't completely extinguish the Roentgenizdat movement, but with the increasing availability of reel-to-reel tape recorders in following years, music fans could duplicate tracks in their own homes, negating the need for a vulnerable blackmarket system.
See this gallery for more Roentgenizdat images - clicking on the song titles will also allow you to listen to an mp3 of each recording. Read more Roentgenizdat history here, and here, and if you're interested in a more metaphorical angle, click here to listen to a lecture/discussion on the connections between music, image, and methods of reproduction, titled "Music on Bones" by writer/scholar Eduardo Cadava, who has written a book by the same name. Now, rock on.