Methods and systems for illuminating areas or objects in areas by manipulating the spectral power distributions (SPDs) of light sources. In one aspect, light of a given desired correlated color temperature (CCT), white in one example, is adjusted by a metamer to a different SPD designed to produce improved perceived brightness by observers. This retains the desired CCT but can allow for such things as reduced number of light fixtures or light sources, less energy, and/or longer effective light source lives for the same perceived brightness of conventional lightings. In another aspect, composite SPD regardless of CCT can be manipulated for other benefits such as highlighting portions of or objects in the area, or improving lighting performance for such things as weather conditions (e.g. snow or fog) or ambient conditions (e.g. twilight).