EP3511174

Provided are a lithographic printing plate precursor including an aluminum support, and an image recording layer on the aluminum support, in which the aluminum support includes an anodized film on a surface of the image recording layer side, the anodized film has micropores extending in a depth direction from the surface of the anodized film on the image recording layer side, an average pore diameter of the micropores in the surface of the anodized film is greater than 0 µm and 0.03 µm or less, an average maximum diameter of the micropores inside the anodized film is in a range of 0.04 µm to 0.30 µm, an average value A nm of thicknesses of surface opening portions and an average value B nm of thicknesses of internal maximum diameter portions satisfy a relationship of 2.5 ≤ B/A ≤ 28.0, and the image recording layer contains an acid color former; a method of preparing a lithographic printing plate using the lithographic printing plate precursor; and a lithographic printing method.