We present a theoretical and experimental study on the effect of progressive porosity increase,through multiple oxidation/oxide removal steps, upon the optical characteristics in threedimensionalmacroporous silicon. It is shown that, by increasing porosity, optical features can bepushed toward higher frequencies. Optimum porosities exist where normal or omnidirectional totalreflection bandwidths are maximized, doubling the initial values. Results are confirmed experimentallythrough angle-resolved reflectance and thermal emission measurements.