Method and apparatus for image reading and image forming, with shading operation control for increased throughput

This document claims priority and contains subject matter related to Japanese Patent Application No. 11-374270, filed on Dec. 28, 1999, and the entire contents of which are hereby incorporated herein by reference. A method and apparatus for image reading and image forming. A shading operation is performed by initially setting an operation parameter necessary for the shading operation and an image reading operation. The shading operation is then performed, an image reading operation is executed, and a further shading operation is then performed after the image reading operation. An operation parameter is then again set when a preparation of a next image reading operation is completed, an image reading operation is performed, and then a further shading operation is performed.