Double Coat Colors
As their name implies, double coat tubes have been coated twice to yield their unique and vibrant colors. The tubes are coated first with a pigment and then coated a second time with a fluorescent material. This process traps the pigment between the inside wall of the tube and the phosphor coat. The pigment then acts as a filter through which the light emitted from the fluorescing second coat flows.
Double coat tubes perform best in gentle curves and straight sections. Due to the relatively fragile nature of the pigment coating, double coat tubes are not recommended for use in tight bends. The pigment coating may thin in tight bends, thus causing color shift in those areas. In general, a cooler bend with minimal stretching is preferred.
With the exception of BL80 Neon Red, double coat tubes are intended for use with argon/mercury fill gas. The color of some double coat tubes may vary slightly when neon fill gas is used.