Black Sabbath release 'Debut'
13 February 1970
When the album Black Sabbath was unleashed on the record buying public in 1970, no one had heard anything like their slow, sludgy heavy rock sound before. The label promoted Sabbath as being "louder than Zeppelin," but at that time no one expected that the album would even chart, let alone end up in the top 10 (not bad for an album recorded in 12 hours). The guitar sound heard was largely down to Tony Iommi and an accident he had while working at a sheet metal factory at the age of 15.
Iommi had accidentally cut off the ends of his third and fourth fingers in a cutting machine. In a desperate bid to play guitar again, Iommi fashioned some makeshift finger tips out of melted plastic and leather and relearned the guitar. It was a painful process and eventually he ended up detuning the strings to lessen the strain on his fingers. In doing so discovered a new, heavier guitar sound...
Sabbath's idea (according to Osbourne) was to 'make music that would scare people'; their darker lyrical themes of death and references to Satan seemed to resonate with those tired of the 60s optimism and flower power and were looking for something altogether harder and darker.