Yellow Indexing/Transmission/Haze

 

Transmission,normally plotted against wavelength is measured using a sprectrophotometer in accordance with ASTM D 1003. This method uses a collimated light source, an intergrating sphere and a detector.


Yellowness is defined in ASTM D 1925 as the deviation in chroma from whiteness in the dominant wavelength range of 570-580 nm, procedure performed using a spectrophotometer.


Yellow Index is calculated based on a primary standard, magnesium oxide. A positive change indicates increased yellowness and a negative change indicates decreased yellowness.