At GLOW you can choose a standard developing solution or an express solution. Your tan is applied with an airbrush spray gun, by a certified spray tan artist. The standard solution remains on your skin for a minimum of 8 hours before showering. The express solution MUST be rinsed off within 2 - 4 hours. * 2 hours for a light tan * 3 hours for a medium tan * 4 hours for your darkest tan.