A method is described which improves the signal‐to‐noise ratio in soft x‐ray appearance potential spectroscopy (SXAPS). The incoming photon beam is filtered ahead of the detector by means of thin metallic foils or organic films, resulting in reduction of very low energy photons which produce unwanted noise in the detector. A specific example is given of the use of a 6.3 &mgr; aluminum foil filter in the study of samarium M spectra.