Abstract-This paper revisits classical Lucas-Kanade (LK) and Horn-Schunck (HS) optical flow techniques. The aim is to provide a baseline for other researchers on these two timeless techniques. The formulations presented incorporate modern practices, namely multichannel, multi-resolution with refinement procedure (warping), non-quadratic penalisers and non-linear formulation of the brightness assumption. The experiments conducted demonstrate the performance enhancement that can be assigned to each modern practice. Thereby, the performance of the LK and HS is renewed in order to enable a fair comparison to other state-of-art techniques.