Ca1-xCdxS microcrystalline samples, prepared by sintering of the constituent compounds at 1325 K, yielded intense broad band fluorescent materials at 77 and 295 K. At room temperature, excitation at 298 nm gave peak emission wavelengths which shifted from 370 to 410 nm between x = 0.000365 and 0.0164 with FWHM rising from 80 to 125 nm. Excitation at 77 K in the wavelength range 150-310 nm permitted optimisation of the brightness with emission peaks at 345, 385 and 370 nm depending on the exciting wavelength and x. The role of cadmium as an emitting centre is discussed.