Adjusting Curve Points With Precision
Once you've plotted a point on a curve in the Curves dialog (Command-M [PC: Control-M]), you can adjust these points by clicking-and-dragging them, but many people find it easier to plot the point by using the Up/Down Arrow keys on their keyboard. This adjusts the Output of the point in increments of 2. To adjust the Input, use the Left/Right Arrow keys. To make larger moves, hold the Shift key while using the Arrow keys and your points will move in increments of 15.