Home » Tip of The Day » Quickly Mask Out a LayerQuickly Mask Out a Layer December 10, 2015. Posted in: Tip Of The Day. If you press the Alt (Mac: Option) key and click on the Layer Mask icon in the Layers panel you will create a mask that is filled with black, which will mask out the entire layer (turn it invisible). « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: