1. A printing apparatus comprising: an imaging device that captures an image of an object; and a control unit that controls a discharge amount of droplets of a printing unit that discharges the droplets to form an image, wherein the control unit acquires a captured image of a test pattern formed by the printing unit from the imaging device and controls the discharge amount of the droplets on the basis of a grayscale value of a first region including an outer peripheral edge of the test pattern in the captured image and a grayscale value of a second region within the test pattern; wherein the control unit sets a limit value of the discharge amount of the droplets; wherein the control unit calculates an evaluation index for evaluating a difference in density between the first region and the second region on the basis of grayscale values of pixels in the first region and grayscale values of pixels in the second region, to thereby set the limit value on the basis of the evaluation index.