We present a new approach to lighting design for image synthesis. It is based on the inverse problem of determining light settings for an environment from a description of the desired solution. The method is useful for determining light intensities to achieve a desired effect in a computer simulation and can be used in conjunction with any rendering algorithm. Given a set of lights with fixed positions, we determine the light intensities and colors that most closely match the target image painted by the designer using a constrained least squares approach. We describe an interactive system that allows flexible input and display of the solution.