WE CLAIM:
[Claim 1]
A lithographic printing plate precursor comprising an aluminum support and an image recording layer,
wherein the aluminum support includes an aluminum plate and an anodized film of aluminum formed on the aluminum plate,
wherein the anodized film is positioned closer to the image recording layer than the aluminum plate is,
wherein the anodized film has micropores extending in a depth direction of the anodized film from a surface of the anodized film on the image recording layer side,
wherein the micropores have an average diameter of more than 10 nm but not more than 10 0 nm at the surface of the anodized film, and
wherein the surface of the anodized film on the image recording layer side has a lightness L* of 70 to 100 in a L*a*b* color system. [Claim 2]
The lithographic printing plate precursor according to claim 1,
wherein a steepness a45 representing an area ratio of portions having an inclination of at least 45° at the surface of the anodized film on the image recording layer side as determined by extracting components with a wavelength of 0.2 to 2 um is not more than 30%. [Claim 3]
The lithographic printing plate precursor according to claim 2,
wherein the steepness a45 is not more than 20%. [Claim 4]
The lithographic printing plate precursor according to any one of claims 1 to 3,
wherein the average diameter is from 15 to 6 0 nm. [Claim 5]
The lithographic printing plate precursor according to any

one of claims 1 to 4,
wherein the lightness L* is from 75 to 100. [Claim 6]
The lithographic printing plate precursor according to any one of claims 1 to 5,
wherein a specific surface area AS is not less than 20%, the specific surface area AS being a value determined by Formula (i) :
AS = (Sx - So) / So x 100(%) ... (i) using an actual area Sx obtained, through three-point approximation, from three-dimensional data acquired by measurement at 512 x 512 points in 25 urn square of the surface of the anodized film on the image recording layer side by means of an atomic force microscope and a geometrically measured area
So.
[Claim 7]
The lithographic printing plate precursor according to claim 6,
wherein the specific surface area AS is from 20% to 40%. [Claim 8]
The lithographic printing plate precursor according to any one of claims 1 to 7,
wherein each of the micropores has a large-diameter portion which extends from the surface of the anodized film to a depth of 10 to 1000 nm and a small-diameter portion which communicates with a bottom of the large-diameter portion and extends to a depth of 20 to 2,000 nm from a communication position between the small-diameter portion and the large-diameter portion,
wherein an aperture average diameter of the large-diameter portion at the surface of the anodized film is 15 to 100 nm, and
wherein an aperture average diameter of the small-diameter portion at the communication position is not more than 13 nm. [Claim 9]
The lithographic printing plate precursor according to any one of claims 1 to 8,

wherein the image recording layer contains a polymeric compound in a form of fine particles, and
wherein the polymeric compound in the form of fine particles is a copolymer of styrene-(meth)acrylonitrile-poly(ethylene glycol) monoalkyl ether (meth)acrylate compound. [Claim 10]
The lithographic printing plate precursor according to any one of claims 1 to 9,
wherein the image recording layer further contains a borate compound. [Claim 11]
The lithographic printing plate precursor according to any one of claims 1 to 10,
wherein the image recording layer further contains an acid color former. [Claim 12]
The lithographic printing plate precursor according to any one of claims 1 to 11, further including an undercoat layer between the aluminum support and the image recording layer. [Claim 13]
The lithographic printing plate precursor according to claim 12,
wherein the undercoat layer contains a compound having a betain structure. [Claim 14]
A method of manufacturing a lithographic printing plate, comprising:
an exposure step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 13 to form exposed portions and unexposed portions; and
a removal step of removing the unexposed portions of the lithographic printing plate precursor having been imagewise exposed. [Claim 15]
A printing method, comprising:

an exposure step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 14 to form exposed portions and unexposed portions; and
a printing step of performing printing by supplying at least one of printing ink and fountain solution to remove the unexposed portions of the lithographic printing plate precursor having been imagewise exposed, on a printing press.