Photoluminescent (PL) System
An LLL system which uses PL material. Photoluminescent material contains a chemical (example: zinc sulphide) that has the quality of storing energy when illuminated by visible light. The PL material emits light which becomes visible when the ambient light source is less effective. Without the light source to re-energize it, the PL material gives off the stored energy for a period of time with diminishing luminance.
Source: Resolution A.752(18), Guidelines for the evaluation, testing and application of low-location lighting on passenger ships, 4 November 1993, International Maritime Organization, Regulatory guidance