by Julieanne Kost
With the On-image tool selected on the Curves Adjustments panel (that’s the one that looks like the hand with the up/down arrow – otherwise known as the “scrubby slider”, as oppose to any of the eyedropper tools), hovering the cursor in the image area will display a preview circle (bouncing ball) over the corresponding value on the curve.
• Click in the image area to add a point to the curve.
• Click and drag up/down in the image area to add a point on the curve to lighten/darken the targeted value or
• Use the up / down or left/right arrows to move the selected point. (Add the shift key to move it in larger increments.)