Blend with a Layer Mask

This white rectangle is the Layer Mask, and by painting black into it, you’ll create a ‘hole’ and reveal the image from beneath. To do this in a subtle and controllable way, press D then X to set black as the foreground colour, then press B to select the Brush tool. In the Options bar at the top of the screen, choose a soft-edged brush and set Opacity to 10% (which you can do quickly by pressing 1). Use the square bracket keys to adjust the brush size, then paint into the bland sky to see the darker sky show through. Take care not to leave a ‘halo’ at any of the joins, and vary your brush Opacity, if needed, to get a naturallooking blend.