Check processing involves scanning a back of a check having no authorization data printed thereon and also scanning a front of the check having preprinted magnetic ink characters, electronically generating authorization data indicating that processing payment of the check has been completed and the check is valid based on a reading of the magnetic characters and a response from an external analysis source, generating an electronic merged image by electronically combining back image data captured during the scanning of the back of the check with generated authorization data, and storing the electronic merged image with the front image data captured during the scanning of the front of the check. Moreover, these operations are performed in a single pass of the check in one direction through a transportation path of a check processing apparatus. No printing of any data is required. The check processing can be embodied in a method, apparatus, or instructions embodied on a machine-readable medium.