The panel needed to function as both a visual interface and a backlit display, meaning every ink layer had to meet tight opacity tolerances - blocking light where required while allowing controlled transmission through symbol areas. Multi-pass registration accuracy was critical across the full batch of 2000 units, with zero tolerance for misalignment between layers. The finished print also had to withstand daily mechanical contact and a temperature range of -30°C to +100°C. While maintaining the curve radius.