The ARA Lifteime Pressure-Sensitive Paint (PSP) system has been developed from the ISSI (Innovative Scientific Solutions Inc) PSP systems. ARA has developed a highly productive and flexible system that can offer simple visualisations of surface pressures up to fully calibrated pressure distributions mapped onto a 3D mesh. The ARA system is capable of providing full 3D coverage of complex wind tunnel models within the ARA Transonic Wind Tunnel (TWT). The system has also been designed to be portable for use in other facilities, either at ARA or at customer sites. Academic papers on the application of this system in the ARA TWT are available from the document download area of this website. Lifetime PSP measurements are captured by taking two images, one of the direct illumination of the painted surface and the second capturing the emission from the paint during it's decay period or lifetime.The surface pressure affects the intensity of the emission from the paint, these intensity variations can then be calibrated to real pressure values.