Spectrally resolved photoconductivity (PC) of p-type porous silicon (PS) samples was measured using a transparent liquid contact which ideally fills the pores. Lock-in detection of the photocurrent allows one to separate the substrate and the porous layer signals by detecting phase changes during the wavelength scan. The in-phase signal component with the substrate response characterizes the transmission of porous silicon, while the out-of-phase component is related to the actual PC of the PS film.