Patent attributes
An image reading apparatus and method are provided which precisely correct shading due to dispersion of the spectral sensitivity characteristic of a reading area of a reading device. Second correction values for correcting, for each of R, G and B, shading due to partial dispersion of spectral characteristics of color separation filters are respectively set and stored for each film type and for each of a plurality of blocks forming an image, on the basis of results of reading a film for correction value setting. Then, from the stored second correction values, correction values corresponding to a type of a film which is an object of reading are retrieved to derive correction values for each pixel by interpolation. The derived correction values for each pixel are added to first correction values for correcting shading due to irregularity in the amount of light or the like.