 Some cameras introduced anti comet-tail circuits to provide dynamic correction, when an overload was sensed (ACT circuits), but these were not used in the EMI 2001.The problem was not satisfactorily resolved until the late 1960s when an extra ‘anti-comet-tail’ gun was introduced into plumbicon tubes.New camera designs, produced in the 1970s, were able to include the new improved tubes, and usually did so.