Patent ID: 7950768

Claim:
A method of calculating a correction value, comprising: forming a test pattern by ejecting a liquid by a liquid ejecting apparatus, which has a first nozzle row in which a plurality of nozzles ejecting the liquid to a medium are arranged in a predetermined direction and a second nozzle row in which a plurality of nozzles ejecting the liquid to the medium are arranged in the predetermined direction, the second nozzle row being disposed so that an end portion on one side thereof in the predetermined direction overlaps with an end portion on the other side of the first nozzle row in the predetermined direction, to an area of the medium corresponding to certain pixel data on the basis of the certain pixel data from first nozzles belonging to the end portion on the other side of the first nozzle row and second nozzles belonging to the end portion on the one side of the second nozzle row; acquiring a read-out gray scale value by allowing a scanner to read-out the test pattern; and calculating a correction value used to correct the pixel data corresponding to the area to which the liquid is ejected from the first and the second nozzles on the basis of the read-out gray scale value; wherein in the forming of the test pattern, the gray scale value represented by each pixel data for forming the test pattern is converted into dot data representing a dot size of a dot to be formed in the area of the medium corresponding to each pixel data by a halftone process, and a dot having a dot size equal to- or smaller than the dot size represented by the dot data of the certain pixel data is formed in the area of the medium corresponding to the certain pixel data by each of the first and the second nozzles.