An image forming apparatus reduces the wait time before completion of an image stabilization process executed for preparation for image formation while ensuring image quality. In the image forming apparatus, image formation is performed using developers having four colors respectively (yellow, magenta, cyan, and black). The image forming apparatus has a monochrome mode in which only black color is used, a full color mode in which four colors are used and an automatic color selection (ACS) mode in which one of the monochrome mode and the full color mode is selected by automatically recognizing image data and image formation is carried out in the selected mode. One of the monochrome mode, the full color mode, and the ACS mode is set to a default mode upon turning on the image forming apparatus. The image stabilization process is then executed based on the default mode.