The RCA 8850 photomultiplier has a wavelength‐dependent luminescence background when used in the UV below 320 nm. We show that this luminescence gives rise to an additional decay in the deconvoluted fluorescence and, unless corrected for, seriously interferes with the resolution of closely spaced fluorescence decays. A much lower luminescence background is found for the RCA C31000M photomultiplier, which is identical to the 8850 except that it has a fused silica rather than a Pyrex window. Use of the C31000M improves the resolution of known mixtures, but the recovered lifetimes are still somewhat in error. We believe that this residual error is due to additional low‐amplitude components in the fluorescence which cannot be resolved. An approach is presented which minimizes the effects of these contaminant decays on an analysis. Using this method, the decays of mixed compounds with lifetimes of 8.8 and 12.8 ns, of 10.1 and 12.8 ns, and of 8.8 and 10.1 ns are accurately resolved.