ISO brightness, D65 brightness, etc. are usually used by the paper industry to evaluate the whiteness of paper. Then although they are all brightness, ISO brightness and D65 brightness are often confused. In Sun Zhaoyi's "Precautions for Using Whiteness Meter", the difference between the two is compared.
There is no specific definition of whiteness in my country's paper industry standards, and ISO brightness and D65 brightness are usually used to evaluate the whiteness of paper. The whiteness mentioned by the paper industry should be D 6 5 brightness accurately, so some newly released product standards have removed the whiteness and renamed it brightness.
To put it simply, the whiteness commonly referred to in the paper industry = the brightness in my country's paper product standards = D65 brightness, and the brightness measured according to GB/T7974 "Paper, Cardboard and Pulp - Determination of Diffuse Reflection Factor" should be D65 brightness. Not ISO brightness. The difference between the two is as follows:
Note: The sample without fluorescent whitening agent is selected from the paper industry whiteness (brightness) level three reference standard paper sample #3, and the D65 brightness is 83.6%; the sample containing fluorescent whitening agent is selected from the paper industry whiteness (brightness) level three Grade reference standard paper sample #4 paper sample, the D65 brightness is 108.0%, and the F value is 22.5%.
