Brush control — the ones that pay off most

  • [ and ] — brush smaller / larger. You will use these more than any other key.
  • Shift + [ and ] — softer / harder edge.
  • Number keys — set opacity (5 = 50%). Press two digits quickly for precision.
  • Alt — temporarily switch to the eyedropper while painting. Sample and carry on without changing tools.
  • X — swap foreground and background. Essential when masking.
  • D — reset to black and white.

Navigation

  • Spacebar — hold to pan with any tool active.
  • Ctrl/Cmd + 0 — fit to screen. Ctrl/Cmd + 1 — 100%.
  • Tab — hide all panels. F — cycle screen modes.

Layers

  • Ctrl/Cmd + J — duplicate layer, or copy a selection to a new layer.
  • Ctrl/Cmd + Shift + Alt + E — stamp all visible layers into a new one. The most useful long shortcut in the program.
  • Ctrl/Cmd + G — group. Ctrl/Cmd + E — merge down.
  • Alt-click between layers — clipping mask.
  • Ctrl/Cmd-click a thumbnail — load it as a selection.
  • Alt-click the eye icon — solo that layer.

Selections and transforms

  • Ctrl/Cmd + D — deselect. Ctrl/Cmd + Shift + D — reselect.
  • Ctrl/Cmd + Shift + I — invert selection.
  • Ctrl/Cmd + T — free transform. Hold Alt to scale from the centre.
  • Ctrl/Cmd + Alt + Z — step backward through history (plain Ctrl/Cmd + Z toggles).

Make your own

Edit → Keyboard Shortcuts assigns a key to any menu command. Worth doing for Flatten, Image Size, and any filter you run constantly. If you reach for a menu item more than a few times an hour, it deserves a key.