Replace the Sky in Photoshop (with Reflections)
In this tutorial you’ll replace a washed-out sky with a dramatic one and make it reflect in the water—all in Photoshop. You’ll use the Blue channel’s contrast with Blend If for a clean sky swap, then protect foreground elements with a mask. Finally, you’ll match brightness and fine-tune for a seamless composite.
Step-by-step instructions
Evaluate channels to plan the blend
Disable the new sky layer in the Layers panel.
Go to Window → Channels.
Click the Blue channel and note the high contrast: bright sky, dark foreground.
Click RGB to return to the composite, then go back to Layers.
Mask and position the replacement sky
Enable/select the sky layer.
Choose the Rectangular Marquee Tool and drag a selection over the sky area.
Click the Layer Mask icon to hide non-selected areas.
Select the Move Tool and drag the sky to align with the original horizon.
Create a sky reflection on the water
Duplicate the sky layer (Ctrl+J on Windows / Command+J on macOS).
Free Transform (Ctrl+T / Command+T), right-click → Flip Vertical.
Drag the flipped copy down to meet the bottom edge of the original sky layer.
Nudge to line up precisely with the horizon for a clean seam.
Hide the original sky with Blend If
Drag the Background layer above the two sky layers.
Click the fx icon → Blending Options to open Layer Style.
In Blend If, choose Blue from the dropdown.
Drag the white point of This Layer left to hide bright sky areas.
Alt/Option-click the white point to split it; drag the left half further left for a smoother transition, then click OK.
Restore foreground areas affected by Blend If
Duplicate the Background layer (Ctrl+J / Command+J).
Right-click the double-square icon on the layer → Clear Layer Style.
Choose the Quick Selection Tool and roughly select buildings, the bridge, icy areas, and their reflections.
Click the Layer Mask icon to keep only your selection and hide everything else.
Match brightness and fine-tune
Select the top sky copy layer.
Click Create New Fill or Adjustment Layer → Levels.
In Properties, drag the black point to the right to brighten the sky; adjust the midpoint for contrast.
Refine: tweak Levels, Blend If split points, and layer masks for a seamless result.
