Yellow index
Laboratory > Optical
| Yellow Index (ASTM E313) | |
| The yellowness index is a number calculated from spectrophotometric data that describes the change in color of a test sample from clear or white to yellow. This test is most commonly used to evaluate color changes in a material caused by real or simulated outdoor exposure. Test procedure The packaging, handling and preparation of the test sample (preferably without cleaning) can affect the test results by modifying the sample surface. Since YI tests are often a series of comparative measurements over long periods of time, these factors must be defined and documented before any test. The Gardner spectrophotometer is highly automated. After specifying the illuminant, the observer angle and the reference color, the test sample is inserted into the sample holder and the spectrophotometer takes the reading. Multiple samples should be measured and the readings averaged. |  |