W5DXP wrote:
I don't think there's anything to argue about. From _Optics_, by Hecht:
"We define the reflectance R to be the ratio of the reflected power to
the incident power."

He certainly wasn't including Max Born and Emil Wolf when he said "We".
They define reflectance in terms of indices of refraction i.e.
(n1-n2)/(n1+n2).

73, ac6xg