In all color fastness tests, testing the fabric's response to light may be one of the most important test items. Of course, the performance of the fabric in the washing, dry cleaning, rubbing, sweating and post-exposure of the fabric in different types of solutions is of vital importance to the manufacturer. But because the fabric is sensitive to light sensitivity, and difficult to predict, so accurate and reliable test is quite critical. For many manufacturers, the light fastness test is an important part of R & D and quality control. However, it is also one of the most difficult to master the test. Because most of the material in the sunlight takes months or even years to react, so the fabric in the practical application of the environment in the natural light test is not feasible. Not to mention how many R & D departments are willing to wait patiently? Many manufacturers choose to test the lab. They simulate natural light to speed up the testing process. The most...