1. An image forming apparatus that forms an image using color materials of a plurality of colors, the image forming apparatus comprising: an image forming unit that forms a test pattern on printing material using the color materials of a plurality of colors; a reading unit that reads the test pattern formed by the image forming unit on the printing material; and a control unit that controls an amount of color material of each color by changing an image forming condition in accordance with a result of reading by the reading unit, wherein the image forming unit forms a mixed pattern image, as the test pattern, in which color materials of a plurality of chromatic colors are used, the control unit controls an amount of color material of a single color based on a result of reading the mixed pattern image by the reading unit, the image forming unit forms a mixed pattern image and a plurality of single color pattern images as pattern images for controlling an amount of color material that has a characteristic of a hue change amount being marked around a maximum amount of color material among the color materials of the image forming apparatus, and the image forming unit forms a plurality of single color pattern images as pattern images for controlling an amount of color material that has a characteristic of a hue change amount being smaller than a hue change amount of the mixed pattern image around the maximum amount of color materials among the color material of the image forming apparatus.