Deteacting if im NOT colliding with somthing

Hi, I’m new to unity and I’m making a game in black and white. The game is about hiding in the dark and sneaking past the guards. I created two background tile maps, one for white background and the other for black. I’m trying to detect when I’m hiding in the black. I made it so it detects when I’m touching the black but I need to know when I’m NOT touching the white. Practically speaking I need to figure out when I’m not colliding with the white background. I’ve tried everything I can think of and also I searched online. Can someone please help. Thank you.