The sensitivity of a grazing incidence grating spectrograph has been derived from measurements of the absolute efficiency of the diffracting element, a Bausch and Lomb catalogue grating, and of the response of the recording emulsion, Ilford Q2 and Kodak Kodirex. Results are presented for wavelengths between 8 and 44 AA, obtained as K-line emissions from electron-bombarded targets, incident on the grating at an angle of 88 degrees .