We report the results of an extensive optical characterization of the properties light-emitting porous silicon (LEPSi), using optical techniques such as Raman spectroscopy, FTIR, cw photoluminescence (PL) and time-resolved PL spectroscopy. Additional insight is obtained from several nonoptical techniques, such as optical and electron microscopy, atomic force microscopy, and various surface physics tools. We examine how to control the surface passivation of LEPSi and what the consequence for light emission are. Samples with widely different surface chemistry have been prepared by controlling the electrochemical processes during anodization or by selected post-anodization treatments such as low- and high- temperature oxidation. In particular, we discuss the relationship between the presence of Si-H, Si-O-H, and Si-O bonds, and the relative strengths of the red PL line have a microsecond(s) ec decay time and the blue PL having a Nsec decay time. These results are compared to the predictions of the leading models that have been proposed to explain the efficient room-temperature luminescence of porous silicon.