The status filter or filter set is specific to a product or emulsion type and is dependant on the use of the material.
This is a single filter used to measure the density of monochrome positive films.
The spectral response of the filter in combination with the photocell and light source produces sensitivity similar to that of the human eye, hence V for Visual.
These are sets of three filters, Red, Green and Blue for measuring colour densities of positive colour materials.
The filters and densitometer combine to have a similar sensitivity to the human eye.
The original filters used were Status A. Some years ago as photocells were slightly altered Certified AA were introduced for modern equipment
Status A densities can be plotted on tri-linear graph paper to give a display that indicates the visual hue and saturation of a patch, step or image measured. The brightness is not indicated on this form of display. This procedure is ideal for comparing different dye systems to see if they have similar visual appearances, for example in the reproduction of an old dye in a colour film to the reproduction of it by a modern subtractive colour film.
These are sets of three filters, Red, Green and Blue for measuring colour densities of negative colour materials.
The filters and densitometer combine to have a similar sensitivity to the Eastman Color Print Films.
The original filters used were status M. Some years ago as photocells were slightly altered Certified MM were introduced for modern equipment.
This is a single filter used to measure the density of sound tracks on print films.
The spectral response of the filter in combination with the photocell and light source produces sensitivity similar to that of the sound photocell of a projector, hence S for Sound.
It is not used for measuring negative sound tracks.
Several other status filters are in use but the only one likely to be seen in the motion picture industry are loosely called Status D.
These are often fitted to densitometers used for still photography and are a reasonable alternative to both A and M but should not be considered very precise.
Status D is quite good enough to use for comparative process control work but is not quite precise enough for setting up colour duplication systems.