a film densitometer for generating digital density values as a function of analog transmittance signals received at an input . a comparator coupled to the input compares the transmittance signals to one or more range references characterizing a plurality of ranges of transmittance signal magnitudes , and provides digital transmittance range signals as a function of the comparison . an amplifier amplifies the transmittance signals to provide amplified transmittance base signals . a gain control circuit coupled to the amplifier and the comparator controls the gain factor of the amplifier as a function of the magnitudes of the transmittance signals . the amplified transmittance base signals are converted to digital transmittance base values by an analog - to - digital converter . a lookup table of data characterizing the logarithmic relationship between transmittance base values and density base values is stored in base memory . a lookup table of data characterizing the relationship between the transmittance range signals and range gain values is stored in range memory . a digital processor accesses the memory as a function of the transmittance base values and transmittance range signals , and generates the digital density values as a function of a sum of the density base values and range gain values .