The K Factor rating system maps linear distortions of 2T pulses and line bars onto subjectively determined scales of picture quality. The various distortions are weighted in terms of impairment to the picture.

The usual K Factor measurements are Kpulse/bar, K2T or Kpulse (2T pulse response), Kbar and sometimes K60Hz. The overall K Factor rating is the largest value obtained from all of these measurements. Special graticules can be used to obtain the K Factor number or it can be calculated from the appropriate formula. All types of linear distortions affect the K Factor rating.

Picture effects may include any of the short time, line time, field time, and long time picture distortions. Any signal containing the 2T pulse and an 18 μsec bar can be used to measure Kpulse/bar, K2T (Kpulse), or Kbar. A field rate square wave must be used to measure K60Hz. The FCC composite test signal contains these signal components. See the discussion on Pulse to Bar Ratios.