IMAGE CONVERSION METHOD, IMAGE CONVERSION APPARATUS, AND IMAGE CONVERSION PROGRAM STORAGE MEDIUM

In an image conversion method of performing an image conversion between binary area tonal image-to-binary area tonal image, an image conversion apparatus, and an image conversion program storage medium storing an image conversion program which causes a computer to operate as such an image conversion apparatus, a binary area tonal image is once converted into a multi-level image, and pixel values of the multi-level image are converted. An areal ration of each divided area corresponding to the associated pixel of the multi-value image, of the original binary area tonal image is increased or decreased in accordance with the difference value between the pixel values of the associated pixels between the multi-value image after conversion of the pixel value and the multi-value image before conversion of the pixel value.