Semi-automatic image registration control for a digital copier

In a digital copier having an input scanner and a printer, image placement or magnification errors which relate to the input scanner can be corrected in copies made at the printer. A person feeds into the input scanner a special test pattern sheet. The copy of the test pattern may exhibit readily-detectable image defects, manifest as "readings" which the user can communicate to the computer, such as through a user interface. A control system in the computer can take the readings and use them to correct attributes of prints made in subsequent copying operations.