Fastness tests are tests to determine the extent to which colors on printed or dyed fabrics and garments can withstand various external influences during use. Among these tests, the most demanded fastness tests are: washing fastness, rubbing fastness, water fastness, sweat fastness, chlorine bleaching fastness, chlorine-free bleaching fastness and light fastness. However, fastness assessments are not limited to these. Other fastnesses such as sea water fastness, pool water fastness, ironing fastness, sublimation fastness, dry heat fastness, hot press fastness, burnt gas smoke fastness, frosting fastness, saliva fastness, phenolic yellowing fastness, dye transfer fastness, rust fastness fastness and ozone fastness. fastness measurements are also available. Moreover, fastness tests such as color fastness to dye transfer, alkali fastness fastness, acid fastness fastness, phenolic yellow fastness and color fastness to steam are also carried out. All of these are evaluated by similar methods.

Ozone fastness tests performed by authorized laboratories comply with the following standards:

• AATCC 109 Ozone color fastness at low humidity

This test method is designed to determine how much dyes used in textile products can resist the effect of ozone at room temperature and in an air environment with a relative humidity of not more than 67 percent. When evaluating the test results, the gray scale used in the fading evaluation is used to determine the color change (TS 423-2 EN 20105-A02 Textile - Methods for determining color fastness - Section A02 - Using the gray scale for the evaluation of fading).

During the test, both the fabric sample to be tested and the accompanying fabric are simultaneously exposed to ozone. This exposure time continues until the test fabric exhibits a significant color change. Or, the test is repeated for the specified number of cycles.