A one‐dimensional model is described for illustrating the perturbing effects of mixed photon/electron fields on planar dose‐versus‐depth profiles in lowZmaterials (Z≤20), and at moderate photon energies (0.3–10 MeV). An electron field may arise from photon interactions in filters upstream of a dose‐versus‐depth experiment. The effects of upstream mass, scattering of electrons out of a gap between a filter and the experiment, and differences between the incident electron energy distribution and locally produced KERMA are modeled and compared to Discrete Ordinates calculations. At transitional depths in a dose‐versus‐depth experiment, the distortions can be significant and obscure the profile of the photon component alone.