A method for providing a visible reference marker on a scanning unit for orienting an item to be scanned or copied includes the steps of emitting a light from a light source, guiding the light to a scanning unit having a contact glass scanning surface, and redirecting the light to define an illuminated reference marker substantially adjacent to the contact glass. A reference marker assembly for accomplishing that method is provided, including a light source, a waveguide for guiding light emitted from the light source to a scanning unit having a contact glass, and a redirector for redirecting the light to define an illuminated reference marker adjacent to the contact glass, for orienting an item to be copied or scanned. The light source may be a light emitting diode, and the redirector may be a light diffuser for redirecting the collected light to define an illuminated reference marker adjacent to the contact glass.