_Cmd+L Curves._ Cmd+M Hue/Saturation._ Cmd+U Color Balance. _ Opt+Shift+Cmd+K Menus._ Opt+Shift+Cmd+M imAge Adjustments> Levels. Arrow keys Nudge selection border only, by 1 pixel Arrow keys Whilst move tool selected: nudge selection by 1 pixel S + Arrow keys Nudge using 10 pixel increments w * Quick selection/Magic wand tool x Exchange foreground/background colors y History brush/Art history brush z Zoom tool Hold down O key Hold down A key Zoom out when the Zoom tool is selecte Keyboard Shortcuts.