A special effect apparatus temporally enlarges an input video signal so as to reduce edge intrusion caused by a type of special effect processing and to eliminate color fading due to different sampling frequencies for the luminance and chrominance components of a video signal. The temporally enlarged video signal is formed by sequential selection among three signals: a reference video signal, a preceding video signal which temporally leads the reference video signal and a trailing video signal which temporally lags the reference video signal. Portions of the preceding and trailing video signals are appended to the reference video signal to produce the temporally enlarged video signal which can be processed to create a special effect devoid of edge intrusion.