Book spine release refers to a special manually, mechanically or motor-controlled device with which a gap of several centimeters is set between the individual support plates of the book cradle, into which the book spine can be gently inserted. Modern scanning systems usually allow a setting that can be individually adapted to the respective template.
Often, a book spine release is also combined with a book spine support, which supports the inserted book spine from below the area of the support plates. It also prevents smaller books from slipping through the open gap.