During the late 1930s and early 1940s the prevalent sound recording apparatus was the wax disk cutter. As a consequence of the lack of materials in the Eastern European & USSR war-time economies, some inventive sound hunters made their own experiments with new materials within their reach.

I do not know the name of the inventor who first utilized discarded medical X-ray film as the base material for new record discs; however, the method became so widespread in Hungary that not only amateurs, but the Hungarian Radio made sound recordings on such recycled X-ray films.

Trey Drake, in his paper The Historical Political Development of Soviet Rock Music, gives us a bit more historical perspective on this practice:

Owing to the lack of recordings of Western music available in the USSR, people had to rely on records coming through Eastern Europe, where controls on records were less strict, or on the tiny influx of records from beyond the iron curtain. Such restrictions meant the number of recordings would remain small and precious. But enterprising young people with technical skills learned to duplicate records with a converted phonograph that would “press” a record using a very unusual material for the purpose; discarded x-ray plates. This material was both plentiful and cheap, and millions of duplications of Western and Soviet groups were made and distributed by an underground roentgenizdat, or x-ray press, which is akin to the samizdat that was the notorious tradition of self-publication among banned writers in the USSR. According to rock historian Troitsky, the one-sided x-ray disks costed about one to one and a half rubles each on the black market, and lasted only a few months, as opposed to around five rubles for a two-sided vinyl disk. By the late 50’s, the officials knew about the roentgenizdat, and made it illegal in 1958. Officials took action to break up the largest ring in 1959, sending the leaders to prison, beginning an orginization by the Komsomol of “music patrols” that later undertook to curtail illegal music activity all over the country.

Eerie, beautiful, and brilliant.