1. An image formation apparatus comprising: a storage; and a plurality of image formation sections each comprising plural rotation members, wherein a test pattern is stored in the storage; the plural rotation members form an image of the test pattern on a medium, the image of the test pattern comprises divided images formed by being divided into regions in a main scanning direction and a sub-scanning direction, each of the divided images is formed by at least one preset image formation section out of the image formation sections, and a width in each of the main scanning direction and the sub-scanning direction of the divided images formed by each of the image formation sections covers the entirety of a width of the image of the test pattern, wherein the width of the image of the test pattern in the sub-scanning direction is larger than a width of an image in the sub-scanning direction formed during two or more revolutions of one of the plural rotation members having a rotation period for image formation larger than that for others of the plural rotation members.