An image forming system prints an image including a plurality of objects. At least a part of the objects overlap with one another. The image forming system includes a computer and an image forming apparatus. The image forming apparatus includes a rendering circuit. When the rendering circuit processes the image object, the rendering circuit enhances a resolution of a part corresponding to the object in the image object based on a shape of the object overlapped at an upper side in the image object. When the rendering circuit enhances the resolution of the part corresponding to the object in the image object, the rendering circuit decides a color of the boundary based on the color information.