Home » Tip of The Day » Duplicate and Invert a Layer MaskDuplicate and Invert a Layer Mask January 30, 2017. Posted in: Tip Of The Day. To duplicate a layer mask to another layer, and invert it at the same time; press-and-hold Alt Shift (Mac: Option Shift), then click-and-drag the layer mask thumbnail to any other layer. « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: