Polyurethane (PU) by its nature has a tendency to fade when exposed to ultraviolet light. If the PU holds are to be used outdoor and in sunlight, the color may gradually change to softer tones over time.
This change is more noticable with certain colors including; Pure White, Traffic blue, Jet Black, Purple Violet and FLUO colors.
Pigments such as Red, Yellow and Green, withstand UV light better and remain brighter for longer.
When used indoors, the color of the polyurethane holds will remain unchanged.