Hi @Nathaniel_Jones，
Thanks a lot! I hope to ensure that I understand correctly through a set of data.
I‘ve measured a floor through a portable spectrophotometer. The SCI measurements are X 49.17, Y 50.98, Z 42.41, and the SCE measurements are X 48.16, Y 49.93, Z 41.34.
According to your reply, “specularity” in rad file should be Y(SCI-SCE)=0.0105.
modified X(SCE) = 48.16 / (1 - 0.0105) = 48.67
modified Y(SCE) = 49.93 / (1 - 0.0105) = 50.46
modified Z(SCE) = 41.34 / (1 - 0.0105) = 41.78
I don’t know if this is correct.
By the way, in another topic, @Greg_Ward Greg mentioned that RGB can equal the SCI RGB value when using the Y value for specularity. Does this mean that I can also use XYZ(SCI) to generate RGB channel in rad file without using the modification.