Originally Posted by Jorge
I can understand what you are saying. I am not sure that it is applicable and I am not sure that it is not applicable. The factor that I see is that the sensing unit in the head of the densitometer is still reading only the known light as presented on the light source side of the material. Extraneous light or the absence of it would seem to be of no effect since the sensing unit is flat against the material. I have tried to read densities of samples of the material that I want to use for filters and the readings seem to be reasonably accurate (at least at this juncture). I will try the readings in actual field conditions and see how they hold up. Thanks for your thoughts.