A method of determining the OD of a printed colorant, comprising:determining a visible wavelength region in which the color is at or near saturation; andif a portion of a determination of saturation is found, determining the OD in a wavelength region at which the color is not at or near saturation. The sense amplifier includes first and second PMOS transistors connected to each other at sources of the first and second PMOS transistors, and first and second NMOS transistors connected to each other at sources of the first and second NMOS transistors, to detect and amplify a voltage difference between a specific bit line and a complementary bit line. Then a process having automatic aspects assigns physical storage resources to the LUs responsive to the LU logical groupings.