The technology used for digitization of the astronomical photographic observations (with wide-field plates having larger than 1x1 deg field as detector) from the end of 19th century up to the beginning of 21st century, which were collected in the Wide-Field Plate Data Base (WFPDB) is considered. The preparation of the plate metadata, as well as the used software with the flatbed scanners for digitization, and the standardization of the output images are discussed. The status of the running plate digitization in different astronomical observatories and data centers is presented.