The wavelengths of light used for the Read/Write/Erase processes in Electron Trapping Optical Memory have been shown to be tunable. Simulation and excitation efficiency spectra of nine samples of these IR stimulable phosphors were measured. Tuning was accomplished through compositional modifications of the ETOM<SUP>TM</SUP> pseudobinary host lattice. The host lattice systems investigated were CaS, SrS, BaS, Sr<SUB>x</SUB>Ca<SUB>1-x</SUB>S, and Sr<SUB>x</SUB>Ba<SUB>1-x</SUB>S (0 <EQ X <EQ 1). Shifts in the read wavelength of over 125 nm and in the write wavelength of 5 nm were achieved.