1. A display and/or operating device for controlling machines, comprising: a projection device for projecting an image onto a projection area, said image being an operating interface having an appearance; said operating interface for being projected onto a printing material of a press; said operating interface for being projected onto a printed printing material; an acquisition device for scanning said projection area; a control computer connected to said projection device and to said acquisition device by a connection for controlling said projection device and said acquisition device, said connection of said control computer to said projection device and to said acquisition device is at least one of wired and wireless; and said control computer being programmed: to carry out an analysis of said projection area with said acquisition device; and to control content of said image to be projected as a function of a result of said analysis of said projection area; and to change said appearance of said operating interface as a function of a color of the printing material.