To provide an image forming apparatus and an image formation method with which halftone expression is reproduced with high precision by considering image characteristics generated by generation of a dot gain.

Correction value density (correction value density in a page) for correcting density variation in the page from a density correction value table 42c in the page is acquired, correction value density (image characteristic correction value density) for correcting the image characteristics generated by generation of the dot gain from an image characteristic correction value table 42b is acquired, the correction value density in the page is added to and subtracted from the image characteristic correction value density and a dither pattern is selected from a dither pattern table 42a, based on its results. In an image conversion part 43, binarization processing is performed to a multilevel image stored in an image development memory 41 using the dither pattern to store a binary image in an image formation memory 44. An image formation part 32 forms an image on print media, based on the binary image stored in the image formation memory 44.