Colour fade is principally caused by exposure to ultraviolet light. It affects bright, fairly intense colours that use synthetic colourants.
Many of these colours are perfectly suited to indoors but can change on exterior exposure.
In general, the clean and bright gold, red, pink, orange and violet tones can be expected to fade significantly more than the blue, green and earthy colours. We refer to the resistance of coloured pigment to UV degradation as its “light fastness”.
In practice, very few colours are achieved by using just one pigment or colourant, so it becomes difficult to predict the likely fading of a mixed colour. The degree and rate of fade depends on the amount of exposure to direct sunlight and the intensity of the sunlight. Over time, all colours will show some change. Colours also have varying degrees of “weather-resistance” and their appearance can be altered by moisture, heat and chemical pollutants in the atmosphere.
Another factor affecting colour fading is the thermal properties of the building substrate. Masonry substrates tend to absorb and hold heat fairly well and evenly, whereas lightweight insulation board substrates such as EPS board and FC Sheeting tend to hold out heat transfer to the surface coating system, which can cause more rapid fading.
When selecting a colour scheme for a home or project it is important to keep the potential for colour fade in mind and to seek advice from the coating manufacturer.