An unnatural color change which occurs when combining trapping and spatial filter processing is suppressed. When image data is input, it is determined whether to perform trapping at the position of the pixel of interest of the input image data, and trapping is performed for the input image data. In addition, spatial filter processing is performed for the pixel of interest of the input data, an output of the trapping and that of the filter processing are weighted, and image data to be output is calculated.