Abstract: A method for converting a hard copy original to a digital image by a scanner system having an image line sensor and a transport system for transporting the hard copy original across the image line sensor are provided. The scanner system has several modes of operation, each mode being associated with a predefined original type and each mode assembling either grey lines or color lines for composing the digital image. The method includes determining an optimal mode of operation for converting the hard copy original by transporting a first part of the hard copy original across the image line sensor. Grey lines from the image line sensor are used in the determination, because this allows the hard copy original to be transported three times as fast across the image line sensor. It is still possible to discern originals with color information from scanned originals with only black-and-white information.