You are able to fade your sigils into invisibility, but still tap their magical energy.
Prerequisite: Illumian.
Benefit: You can make your sigils disappear or reappear as a free action. You gain the full benefits of your power sigils even when they are not visible.
Normal: Illumians can douse their sigils or make them reappear with a standard action, and they lose the benefits of their power sigils as long as they are doused.
Source: Races of Destiny, page 154.