Abstract: We present a general linear transform method for handling full spectral information in computer graphics rendering. In this framework, any spectral power distribution in a scene is described with respect to a set of fixed orthonormal basis functions. The lighting computations follow simply from this decision, and they can be viewed as a generalization of point sampling. Because any basis functions can be chosen, they can be tailored to the scenes that are to be rendered. We discuss efficient point sampling for scenes with smoothly varying spectra, and we present the use of characteristic vector analysis to select sets of basis functions that deal efficiently with irregular spectral power distributions. As an example of this latter method, we render a scene illuminated with fluorescent light.