Describes a method for the evaluation of the performance of near-infrared imaging devices to detect underdrawing and reworking of paintings. System analyses were performed on two different near-infrared imaging devices, a Hamamatsu lead sulfide vidicon camera and a Photometrics silicon charge coupled device (CCD) camera. The analyses included modeling of the system spectral response curve by analysis of the system components, as well as considering the limiting resolution and modulation transfer function (MTF). The modeling was confirmed by examination of a test panel at various wavelengths. Calculation of visibility was introduced as a quantitative measure of system performance. This calculation is also discussed as a means to define more clearly the actual performance requirements of these systems. This analysis has revealed the strengths and weaknesses of current systems, and provides guidance in the construction of improved devices.