Quote Originally Posted by L Gebhardt View Post
Another way of saying it is: does it matter how the density got there, other than it was a result of light hitting the film? Either way the curve shows density vs light exposure. So unless you are interested in the physics of how density builds up it isn't important (not that it isn't important in an absolute sense).
I guess from a theoretical perspective (or even a practical perspective depending on magnitude) it might matter how the density got there if each incremental increase in density is not merely due to increasing exposure (light), but also increasing amounts of chemical fog.