quick mask Use 'Q' to activate it. Its one of the lowest buttons on the control list. It resembles a rectangle with a circle in it. The one on the right is to activate it, the one on the left, deactivate. Note, the brush/eraser will only work when in standard mode, not, for example, in multiply/colour burn/dodge/etc. Whatever you paint red will be masked off, so it selects everything but. Then you can invert the selection, and just select the red bit. This is good cause you can mask with any opacity which equals feather level when deactivated. It also lets you mask any shape you can set the brush to. Changing the colour is probably the colour balance tool. Poor job though imo, the video. HAHAHA