The present invention relates to a phantom device that simplifies usage and testing of a low intensity light imaging system. The phantom device includes a body and a light source internal to the body. The body comprises an optically selective material designed to at least partially resemble the optical behavior of mammalian tissue. Imaging the light source or phantom device may incorporate known properties of the optically selective material. Testing methods described herein assess the performance of a low-level light imaging system (such as the software) by processing light output by the phantom device and comparing the output against known results. The assessment builds a digital representation of the light source or test device and compares one or more components of the digital representation against one or more known properties for the light source or the test device.