D-32 September 2009
11
Modulation transfer
function
The MFT curve was determined using a method similar to that described in
ANSI PH2.39-1977 (R1990),
Photographic Modulation Transfer Function of
Continuous-Tone Black-and-White Photographic Films, Method of Measuring
.
Diffuse RMS
granularity
Determined at a net diffuse density of 1.00, using the aperture indicated.
These values represent 1,000 times the standard deviation of density
produced by the granular structure of the material when a uniformly exposed
and developed sample is scanned with a densitometer calibrated to read
American Standard diffuse visual density, and having a circular measuring
aperture with the indicated diameter.
Granularity is an objective measurement of the spatial variation of sample
density that generally correlates with graininess, which is the subjective effect
of the image nonuniformity upon an observation when comparisons are made
at the same density level.
Broadly speaking, granularity measurements with the 48-micrometer aperture
will indicate the magnitude of the graininess sensation produced by viewing
the diffusely illuminated sample with 12X monocular magnification.
NOTE: If the viewing conditions are changed from the specified conditions,
the published RMS values may no longer correctly indicate the relative
sensations of graininess produced by various samples.
48-Micrometer
Aperture Value
48-Micrometer
Aperture Value
2462
5
15
2468/3468
less than 5
10
2470
less than 5
10
