When designing the Touch Board we wanted to create interesting graphics on both sides. The first thing you will notice about the underside of the board is that it is the inverse of the top. In PCB manufacturing colour choice is limited to two layers- the Solder Resist Layer and the Silk Screen Layer., but with a little cunning we simply inverted our graphics on the bottom side and let the white beneath the graphics to peer through. This also added more protection to the bottom traces and raised all the pads by a fraction. This makes the board more stable and ensures the only sections of the board that are exposed are the electrode or ‘touch’ points. Finally, the board needed to be flat on the underside so it would lay flat on a surface painted with Electric Paint and hence we are using all surface mount components in the final version.