one other one and it has a different color scheme though the logo and make clearly match otherwise. Phonozoic shows yet a different label I suspect to be earlier. But unlike most other brands, Rainbo is still with us today! Jack Brown founded Rainbo in 1939 to manufacture his generic paper-core recording blanks. By 1963 he was pressing his own records, and by 1965 they were pressing LPs for capitol records. This year is actually their 75th anniversary.
The side is unlabeled and undated but the songs are easily recognizable. The surface noise drops off after about 10 seconds and the words sung by the unaccompanied female singer become perfectly clear. The first song is "Embraceable You", and the second is "Summertime" both by George Gershwin. Both were in a number of musicals, and performed by entertainers like Fred Astaire, Ginger Rogers, Judy Garland, Billie Holiday, Etta James and many others.
Both songs predate the founding of Rainbo and are little help in dating the disc.While first published in 1928 the peak popularity of "Embracable You" was probably in 1943 with Judy Garland. Summertime was penned a bit later dating to 1935 for the musical Porgy and Bess. The continued popularity of the script really prevents using it for a date as well. But it's notable that the style of these versions is reminiscent of Billie Holiday who covered both tunes before 1936. I suspect for that reason that this blank probably rolled out of Jack Brown's factory before 1943.