1. A method for correcting image plane registration errors for a multi-channel printing system that prints documents by depositing ink onto a print medium that is subject to physical distortions caused by moisture-induced expansion of the print medium, such distortions being dependent on an amount of deposited ink, each document including a set of document pages to be printed on the same side of the print medium, each document page having an associated page number and having associated image data for a plurality of image planes, comprising: designating an image plane registration error database associated with a particular document-type classification to be used in correcting image plane registration errors, the image plane registration error database storing image plane registration error information characterizing registration errors between image planes as a function of page number for each of a plurality of different page-count classifications, the registration errors being caused by physical distortions of the print medium due to the deposited ink, wherein the page-count classification corresponds to the number of document pages in the document; receiving a new document of the particular document-type classification; determining a page-count classification for the new document corresponding to the number of document pages in the new document; determining image plane registration correction values for each document page of the new document that reduce registration errors between image planes caused by physical distortions of the print medium based on the stored image plane registration error information associated with the determined page-count classification, wherein the image plane registration correction values for each document page of the new document are determined based on the stored image plane registration error information for the corresponding page number; and using the multi-channel printing system to print the image data for each document page of the new document, wherein a spatial alignment of the image planes is adjusted responsive to the corresponding determined image plane registration correction values to compensate for the physical distortions of the print medium due to the deposited ink.