Thomas Edison, one of the major innovators of motion photography, wanted to call his recording/projection device a "time machine" of sorts, as it captured everything about the time in which it was made, preserving it for (he thought) all eternity.
I happen to agree with this viewpoint - films are a capture of the time in which they are made, and that INCLUDES what they were made with (film vs. video, color vs. black-and-white). So when you, say, rid the image of all film grain, colorize a black-and-white film, or add a whole bunch of CG alterations to the image, you destroy the "time capsule" aspect of the film. I have no problem with this being done IF THE ORIGINAL IS PRESERVED COMPLETELY, i.e. "Blade Runner"'s five-disc box set, or the 3-disc "Close Encounters" box.
So I'm in the "preserve it as it was made with ALL the technological limitations it was made under" camp. Just so you see where I'm coming from.
Oh, and:
Lowry's first project was Citizen Kane, and not only did they erase dirt, but they erased the grain of the emulsion itself, and it ended up looking like video, it was too clear.
That explains a lot - I always thought my DVD of "Kane" looked a little odd.