How to test the light fastness of the fabric, the test method can be used either in the sun or in the sun machine, that is, the sample and a set of blue wool standard (according to the degree of fading under light irradiation For grade 3), exposure is performed under the specified conditions under the artificial light source equivalent to sunlight, and then the discoloration of the sample and the blue wool standard are compared, and the light fastness rating of the sample is evaluated.
The degree of fading of the sample after exposure was compared with that of the standard color sample. The European standard was divided into 8 grades, with grade 8 being the best and grade 1 being the worst. American standards are divided into 5 levels.
Fabrics with poor light fastness should not be exposed to sunlight for a long time and should be dried in a ventilated place.