An image processing apparatus includes the following elements. A characteristic value calculator calculates characteristic values of a preset area set around a pixel of interest. A trapping determining unit determines, for each color plane of an N-valued image, on the basis of the calculated characteristic values, whether the pixel of interest is to be subjected to trapping processing. A pixel value calculator sets, for each color plane, a position of a reference pixel in a reference area, and calculates a pixel value for changing the pixel value of the pixel of interest on the basis of a pixel value of each color plane at the position of the reference pixel. A pixel-of-interest value changing unit changes the pixel value of the pixel of interest into the calculated pixel value when the trapping determining unit determines that the pixel of interest is to be subjected to trapping processing.