Light Fastness:

It is very difficult to establish a precise correlation between the light fastness of printed fabrics and their durability.Various factors, in addition to light exposure, can affect the print over time (sunlight intensity, humidity, etc.).The following table provides an approximate guide to the relationship between the light fastness rating on the Blue Wool Scale and the expected print durability:

Note: For ratings above Grade 5, if the colour change falls between two grades on the Blue Wool Scale, the light fastness rating is indicated using both grades (e.g. 5–6). If the colour darkens, the letter N is added to the rating.