Aircraft navigational instrument marking - uses additive to grey paint to cause sky-blue colour under UV light

摘要

Aircraft navigation instruments such as artificial horizons which are of spherical form are painted in two colurs. The upper half is usually grey and the lower half is black. These colours are readily distinguished in daylight but when illuminated by ultra violet light during night flying the colours can no longer be distinguised. By adding a small amount of a special azure blue paint know and Blankhophor (RTM) to the grey pain it becomes sky-blue when illuminated with ultra-violet light and is thus readily distinguishable from the black region.