Within a few years of moving to New York, Laswell founded a recording studio with producer/engineer Martin Bisi (of later indie rock renown) and hooked up with Jean Karakos and his fledgling label Celluloid Records. Under the Material moniker (now also a production unit consisting of Laswell and Beinhorn - Maher being long gone - and by 1984 consisting solely of Laswell) Laswell became the de facto house producer for Celluloid until the sale of the label in the later 1980s. During this time in the early to mid-1980s, Laswell was able to record some of his Material excursions (which ran the gamut from experimental jazz/funk to pop and R&B, featuring everyone from avant-jazz figures Henry Threadgill and Sonny Sharrock to Archie Shepp and pop star Whitney Houston) as well as projects such as Massacre, with Fred Frith and Fred Maher.  His association with Celluloid allowed some of his first forays into this so-called "collision music" - the term was coined for Laswell by the British writer Chris May, then editor of Black Music & Jazz Review and later a Celluloid staff member - and forays into world music. Recordings with the Golden Palominos and production on albums by Shango, Toure Kunda and Fela Kuti all appeared on the label. Celluloid also released a slew of 12" devoted to Hip-Hop, becoming a precursor to the popularity the form enjoyed starting in the mid-1980s. Fab 5 Freddy, Phase II and Afrika Bambaataa all appeared on the label. Criminally forgotten, Laswell also put together the very successful 12" World Destruction which paired PiL's John Lydon with Afrika Bambaataa - years before the Run-D.M.C./Aerosmith collaboration broke down the rock/hip-hop barrier. 1982 also saw Laswell's solo debut, Baselines.  Also recording a Laswell-helmed solo album for Celluloid was Ginger Baker, whom Laswell coaxed out of semi-retirement, giving the drummer's career a new boost. He likewise brought Sonny Sharrock out of semi-retirement and produced some of the guitarist's most acclaimed recordings, starting with the solo LP Guitar.

Answer this question "When did he found Celluloid Records?" by extracting the answer from the text above.
- and by 1984 consisting solely of Laswell) Laswell became the de facto house producer for Celluloid until the sale of the label in the later 1980s.