curious80 wrote: So when we go back we do not get any more light rays because everything outside the original area is black.
WRONG !!!
We get the same number of light rays reflecting off the black (unless the black is a black hole that will not allow any light to escape/reflect).
We get the same number of light rays, but the additional amount of energy being absorbed by the black cloth, renders less energy being reflected. The magnitude of the energy is reduced, but the direction remains iaw AI=AR. Thus the amount of energy reaching the sensor is now less and and cannot be converted into as strong of a signal (or is insufficient energy to effect a change to the negative), and is then recorded as black.
AI=AR (absorption & refraction).
Conservation of energy requires that the total amount of energy remain constant and is divided among that which is absorbed (color), refracted (transmitted through translucent/transparent material) and reflected. As the refractive index, angle of incidence and color absorption characteristics change, so does the amount of energy remaining available for reflection.
Nov 06, 2012 at 11:45 PM
Previous versions of RustyBug's message #11098114 « silly inverse square law question. »
