http://www.kodak.com/US/plugins/acrobat/en/motion/support/h1/H1_23-27.pdf
The "signal" in a s/n ratio is always an ideal one. In this case a perfectly uniform film, with no "grains", and an average density equal to the one of the real film.
Bruce Rubenstein wrote:
RMS = Root Mean Squared You still need two different signals for a ratio.
BR
