Time-resolved Schlieren Photography was used to visualise the mixing zones induced by the Richtmyer-Meshkov (RM) instability initiated with four different initial conditions: three of them with monotonic, single-mode shape and one with a non-monotonic, multi-mode shape. Results of this experimental campaign showthat the shape of the initial air-helium interface has an effect on the resultant mixing region. These also confirm that the evolution of the RMI-induced mixing width follows an exponential law. The growth-rate of the mixing width depends on the monotonicity of the initial air-helium interface: while the mixing widths originating from single-mode initial conditions are almost superimposed, a lower growth-rate is found for the mixing width evolution arising from a multi-mode initial condition. The macro-scale Reynolds number based on the width of the mixing zone suggests that both flows initiated with single- and with multi-mode initial conditions reach a fully turbulent state after the reshock phenomenon. The Schlieren Photography visualisations presented here allow to illustrate the flow topologies of the induced mixing and highlight the effect of the initial conditions on the large-scale structures of the RM instability-induced mixing.