In the early 70s, a young Grand Wizard Theodore invented the idea of scratching vinyl when he stopped a record on a turntable with his hand and liked the sound. Little did he know that this would develop into the rhythmic scratching sound now associated with hip-hop DJing and would have a radical effect on contemporary music.
Doug Pray's exuberant documentary charts the rise of the hip-hop DJ from its urban roots to the cultural phenomenon that now sees turntables outsell guitars. Plus it does what all good documentaries do: gratifies hip-hop fans with good research and interesting interviews while remaining accessible for the uninitiated.
Giving a running commentary on hip-hop's evolution, DJs such as Q-Bert, Mix Master Mike and the X-Ecutioners make appearances as both good-humoured interviewees and virtuoso performers, with some of the most memorable scenes being those of impromptu freestyling sessions that take place in somebody's kitchen.
One prominent figure is Afrika Bambaataa, who recalls how he formed Universal Zulu Nation in 1973 - a DJ, rapper, graffiti artist and break dancer collective in New York - as a positive and creative alternative to street gangs.
Similarly, a lot of time is given over to DJ Q-Bert - widely considered to be the most accomplished hip-hop DJ - while at the opposite end of the spectrum, a group of kids in San Francisco take part in an after school scratching club in a record shop.
"Scratch" is visually unfussy, as Pray ditches flashy photography in favour of enthusiastic interviews, good research and a large dose of music - lingering on shots of the DJs' hands working the turntables and fader with unbelievable dexterity. Infectious, enthralling and fun; Pray has really done his subject justice.