The response characteristics of a number of inorganic phosphors have been investigated in the extreme ultraviolet region (∼170A) for the purpose of selecting a luminescent screen suitable for the measurement of relative intensities in conjunction with photo‐multipliers. Preliminary tests indicate that in this spectral region luminescence is excited rather strongly in the tungstates. Sample screens of CaWO4have been studied photographically in order to determine to what extent such screens give rise to a faithful reproduction of the intensity distribution of the exciting radiation. Qualitative calculations show that the luminescent intensity excited by weak soft x‐ray radiation is above the noise level of the conventional photo‐multiplier.