Soundmirror tape (also known as ‘magic ribbon tape’) was a magnetic tape format for use on the Soundmirror tape recorder made by Thermionic Products in the United Kingdom. What was unusual about it was that was made of paper with an oxide coating rather than the standard plastic tape.
Thermionic introduced the Soundmirror tape recorder in late-1948 under licence from the Brush Development Company in the US, after introducing the Recordon dictation disc (also made of paper) earlier in the year. The Soundmirror machine became the first domestic tape recorder on the UK market.
While the Recordon disc was aimed at the dictation market, the Soundmirror format was aimed at longer duration recording such as concerts, meetings and lectures. The tape ran at 7.5 inches per second on a maximum reel size of 7-inches, so allowing up to around 30 minutes of recording.
Production of the Soundmirror continued until 1954 by which time acetate (and later polyester) had become the standard magnetic tape base material.