The MTF [Modulations Transfer Function]curves relate how various locations in the lens' field of view handle sharpness and contrast. It takes some understanding of optics to interpret, however there are no standards so one cannot compare lenses from two different manufacturers. Since each manufacturer has its own standards, on can only compare lenses by a single lens manufacture such as Zeiss for Hasselblad and Leica lenses. See
Modern Optical Engineering by Warren J. Smith
Optics Eugene Hecht
Characteristic curves show the relationships between different color constituents in a color film and the sensitivities
OR the film response to light. See
Principles of Optics by Max Born and Emil Wolf
RMS [Root Mean Square] is used from converting from sinusoidal voltage to the equivalent dc voltage.
Courses in optical and or electrical engineering would be a good starting place.