This position paper presents a proposal for evaluating interaction with light in a mixed reality setup. Current processes of designing and testing new forms of user interaction (UI) for controlling lighting are long and end up being restricted in actually testing a small number of possible interactions. Apart from the apparent advantage of overcoming testing a small number of potential interactions, the advantages of a simulated environment lie in the fact that such an environment is fully controllable and adaptable to the researchers' needs. Finally, we sketch potential challenges of using a mixed reality setup for evaluating interaction with light.