Chromaline UDC Ace is a professional grade screen printing emulsion, with a forgiving exposure range - it tolerates under exposure and over exposure relatively well. UDC Ace has excellent resistance to plastisol, making it a durable choice for long production runs. UDC Ace stores for years on the shelf unsensitized, and once sensitized Chromaline's specifications include a shelf life of 4 to 6 weeks, but in practice we find UDC Acec can last for several months if stored in a cool light-tight cabinet away from heat sources and UV.