Methods for generating a customized spectral profile, which can be used to generate a corresponding filter, lamp or other type of illuminant. A trial spectrum is generated. A reference spectrum is determined or otherwise obtained. A SOURCE spectrum is determined or otherwise obtained. One or more optical indices are calculated using the trial spectrum and one or more of the optical indices are optimized by varying the trial spectrum to generate the customized spectral profile. A radiation force parameter can be used to minimize unsafe build-up of light in spectral regions. Adaptations of color rendering parameters can be used in the optimization process. Smoothing parameters can be used to enable easier design of filter structures. A reflectance camera can be used to measure reflectance data at one or more pixels of a digital representation of an object to be illuminated.