A set of particulate monolayer samples with a δ‐distribution of particle sizes has been produced on Lawsan membrane filters by means of a cascade impactor. The accuracy of a proposed equation for characteristic x‐ray intensity from particulate monolayers of various chemical and granular compositions has been experimentally confirmed. x‐ray spectra of Fe and PbTiO3 powders have been examined following excitation by monochromatic photons.