Method of operating a flexographic printing press, flexographic printing press, system and sleeve

A method of operating flexographic printing presses having an impression cylinder, printing cylinder carrying a sleeve with a flexographic printing forme or cylinder, uses a sensor adjusting print register of the printing forme or cylinder relative to a further printing forme or cylinder and/or adjusts color density and/or implements color inspection. An image of the sleeve surface with printing forme is recorded by a camera and processed before printing, locating a register mark and/or a color measurement field in terms of x-y positions. A sensor automatically moves for recording the register mark to the y-position of the register mark before adjusting to record the register mark and/or a sensor moves for recording the color measurement field to the y-position of the color measurement field before adjusting to record the color measurement field. Cost-efficient, high-quality industrial printing and further automation is provided.