What does light fastness mean?
When textiles are exposed to the sun and thus ultraviolet rays, the fabric coloration changes.
An effect called fading happens which especially can be seen at dark colors.
Upto which extend a textile fades, depends on the fabric composition. There exist dope dyed threads which guarantee a very high light fastness and thus a high durability.
The light fastness of a fabric is determined on a DIN-scale (0-8). On this scale "0" means a very bad light fastness and consequently "8" an extraordinary high one.