Fluorescent light is produced by two primary mechanisms: the mercury arc generates narrow bands of energy in the visible and ultraviolet regions, and the fluorescence of the phosphor coating produces a more balanced, continuous spectrum of visible light. The SPD diagram for the Cool White lamp shows a typical fluorescent response, with several distinct spikes rising above the overall curve. The composition of the halophosphor coating on the Deluxe Cool White lamp has been manipulated to improve the color rendering properties. However, these CRI improvements are achieved by sacrificing efficiency.