What standard do I use to verify Yellowness Index Performance?

There are no physical liquid standards specifically designed to verify the Yellowness Index of liquid samples over time. Yellowness Index is defined as a mathematical function such that a perfect clear of 100% transmission, typically represented by the transmission cell filled with DI water, will have a YI value of 0.

However, a good workaround solution is to use a very stable APHA/Pt-Co liquid standard in the yellowness range of your product as an application diagnostic to monitor your liquid measurement over time. Continue reading