rbnpolanco

I recently installed Paint.net (love it!) and was messing around with effects and colors when I stumbled upon this one adjustment/edit (I'm not sure!) that allowed you to select several colors and make a a threshold and other cool effects with only the colors you selected previously. I thought it was really cool, but I didnt save the photo. I just cant find it! Someone help me, please? It wasn't the recolor tool for sure. Thanks!