It is my belief that the copy firm is using an optical/chemical process. The film I receive doesn't have the black color on the outside of the plastic, like you get with a laser printer. The color seems to be inside the surface of the sheet on one side. It is almost impossible to scratch the plastic to remove the color. And the black is really, really black. Works perfect together with an UW lamp when making PCB. It seems to be a cold process, so I have never seen any problem with registration caused by the plastic changing size. The film is maybe twice as thick as the OH sheets you use in a laser printer, and they are perfectly flat and smooth with shiny surfaces on both sides. For optimum results when making dual-sided boards, one side of the layout should be printed mirrored on the plastic, allowing the side of the sheet with the print towards the PCB.

The clock has the characters placed in a fixed-grid matrix, so it should be possible to use 1x1 or 2x2 or 3x3 backlight diodes for each character position. An advanced student could even select two-color LED matrix modules. And the lack of movement removes one of the challenges since the control of the diodes will not be time-critical.