Evacuation Left Supernova. Supernova evacuation signs have the same appearance in both light and dark, with an afterglow both in the white symbol/pictogram and frame, as well as in the green base colour of the sign. Aluminium for wall mounting. They are best applied using double-sided tape or film. Supernova is a patented working environment sign with a colour afterglow. The sign design complies with standards ISO 7010 (pictograms), ISO 3864 (correct signal colours in daylight and dark) and ISO 16069 (afterglow luminescence).