Originally Posted by CPorter
come on, why should it let neglible light through, sounds like you are agreeing that where I want to read just fog must also have density from light.
NO !!! The black tape used by CPorter as a mask should NOT let any light through. When I used the word negligible I intended it to mean "a sufficiently small amount (of light) that will not contribute to any measurable increase in density". Letting light through the tape that contributes to a density increase is contrary to the intention of using the black tape in the first place !!
Ahh! That clears it up, forum communication can be tricky sometimes-----sorry for my contribution to that misunderstanding.