ZnSe-based LHs exhibit a propensity to oxidize over time under ambient conditions. We previously showed that degradation of ZnSe(ba) in air produces Se nanoparticles and ZnO. The Se nanoparticles produced from degradation have a dark red colour; as such, they reduce the white-light reflectance of the degrading LH sample. This colour change can be quantified by DRS.