1. Apparatus for receiving frames of an input video signal and temporally processing the video signal, comprising: a string of at least three frame store devices connected in series arrangement; means for applying said video signal to the first frame store device of said series string; a combining circuit having at least four weighted inputs; means for applying the outputs of said frame store devices and said input video signal to said combining circuit, at least two of said frame store device outputs being applied with a negative weight, and at least some of said frame store device outputs being applied with a positive weight; the number of frame store devices in the string and the weightings of said combining circuit being selected such that the output of said combining circuit has an increased temporal response with respect to all other temporal frequencies, as compared to said input video signal, in the temporal frequency range around approximately 10 Hertz, whereby the temporal frequency response is enhanced in the range in which the human eye has maximum responsiveness.