Scope:

The Yellowness Index is a number derived from spectrophotometric data that defines the transition from clear to yellow in the color of a test sample. The most common application of this test by ASTM E313 is to assess color changes in a substance caused by actual or simulated outdoor exposure.

Test Procedure:

The BYK Gardner Spectrophotometer has a high degree of automation. The test sample is placed into the specimen holder, and the spectrophotometer takes the reading after determining the illuminant, observer angle, and reference color. Many samples are analyzed and the results are combined. Test sample packaging, handling, and preparation may affect the test results. These factors should be identified and reported prior to any YI testing since it is often a series of comparative measurements over long periods of time.

Sample size:

A sample size of 100 mm disk is generally used.

Data:

Yellowness Index (YI)