The team used an Ultimaker S5 3D printer on default settings with a 0.4mm nozzle/print core, printing at a 0.15mm layer height with conductive filament printed with a 100 per cent infill to maximise conductivity. For spray coating they used an Iwata Eclipse hp-cs airbrush with a 0.35mm nozzle and an AS186 air compressor at a distance of around 30cm. The displays are illuminated with two 9V batteries with a standard EL driver.
As well as powering the EL sprayable display, the electrodes can also serve as capacitance sensors to enable touch sensing. Lacquer layers can be added to the top to create a protective insulating layer and separate the AC current powering the display from the user's touch. Experiments showed comparable capacitive sensing capabilities to channels with no coating.
The paper is at https://doi.org/10.1145/3313831.3376543