Subject: What is the reflectivity of standard 8x11.5' printing paper

..or any other easily obtained material? 

Also, in the case of a digital camera with a flash and a surface:

the magnitude of light is some constant/x^2 where x is the distance in meters
from the source of light, right?
if so, then how much light reaches the camera when the reflecting surface has a
reflectivity of R...
is it R*constant/(2x)^2     or R*constant/x^4

or in plain english, does the light reach the surface, and then reflect, getting
absorbed some, and then move back toward the camera as if the surface was the
emitter (in which case the amount of light = R(Constant/x^2)/x^2 =
R*constant/x^4) or does the light reach the surface and reflect back as if it is
going through the surface, in which case the amount of light would be
Rconstant/(2x)^2.

Or maybe I'm completely wrong :)

-Roman R.

Re: What is the reflectivity of standard 8x11.5' printing paper