Scotch - The Scotch brand and Scotch Tape are registered trademarks of 3M. The company also used the name "Scotch" for its audiovisual magnetic tape products. Scotch was the premier reel to reel recording tape manufacturer since they started production in 1948. Scotch invented Cobalt doping techinque in 1971 producing "High Energy" tape which later was adopted by many companies. They have also contributed to SONY Ferrichrome tape invention. In 1979 they have introduced the first Metal particle tape. Scotch stopped producing its own tape outsourcing it from other companies like BASF and DENON, in 1996 3M exited the magnetic tape business, selling its assets to Quantegy (which is a spin-off of Ampex). The familiar plaid design, a take on the Wallace tartan, was introduced in 1945 and is used on all early Scotch models. Until 1957 the logo was "handwritten" with uneven letters, from 1957 to 1961 the letters became rounded printed. In 1961 the logo was redesigned in the Gothic style, the last rounded thin font appeared in 1981.