An analysis is performed of reflective waves and their mixing during the holographic exposure of a photoresist film. It is shown that the resulting irradiance depends strongly on the reflectivity of the film/ substrate interface and on the optical thickness of the photoresist film. From these results it is possible to find the conditions where a synchronous detection system can be used to monitor and stabilize the recording process on photoresist films on nontransparent substrates. The operation of a negative feedback system to correct fringe perturbations in real time is analyzed for substrates of three different reflectivities. Although only photoresist film (Shipley AZ 1400) is studied, the general results can be applied to all types of photosensitive films or similar systems.