In one or more implementations, the apparatus, systems and methods disclosed herein are directed to calibrating a smart phone with an arbitrary phone case for color lookup applications, wherein the calibration process includes obtaining, with the smartphone without the case equipped, a first measurement data set that includes at least one measurement of each of a black, white and grey calibration target; obtaining, with the smartphone with the case equipped, at least three exposure measurements of a white calibration target at least three different exposure times; calculating an optimized exposure time using at least the at least three exposure measurements; obtaining, with the smartphone with the case equipped, a second measurement data set that includes at least one measurement of each of a black, white and grey calibration target at the optimized exposure time; generating fitting parameters from the first and second measurement datasets; and storing the generated fitting parameters and optimized exposure time in at least one of a local or remote data storage device.