Quote Originally Posted by carney2
I just received the current issue of "Shutterbug" magazine and read one of the cover articles entitled "Our Top 15 Slide Films." In some of the film write-ups they mention "RMS value" and give it a number (usually 8). What does this mean?
Root Mean Square is a "fancy average." For a sine wave, such as the current that comes out of an AC outlet, it is 0.707 of the peak amplitude. For film grain, its basically the same thing for "peak size of the grain." It makes sure that plus and minus values don't cancel each other out. Lower is better.