Home » Tip of The Day » Opacity and Fill Keyboard ShortcutsOpacity and Fill Keyboard Shortcuts September 8, 2016. Posted in: Tip Of The Day. With a non-painting tool selected, press a number key to change the opacity of a layer ( 1 for 10%, 2 for 20%, etc.). Hold the Shift key and press any of the number keys to change the Fill. « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: