Swap a Gray Sky Using Selections – Classic Day 30

How to Replace a Sky in Photoshop

A dramatic sky can transform a landscape, and Photoshop makes swapping one in surprisingly manageable when both photos start as RAW files. In this final lesson of the series you will process two RAW images in Adobe Camera Raw, bring them into Photoshop as Smart Objects, select and mask the sky, refine the edge with Select and Mask, and then, most importantly, match the light and color of the new sky to the foreground so the composite looks real.

The two sample images were shot at the same location with a similar focal length, one before sunrise for the sky and one shortly after for the sunlit mountains. Matching perspective like that makes the swap far more convincing.

Process Both RAW Files

1. Open Both DNGs in Camera Raw

   Open the two DNG files together; they launch directly into Adobe Camera Raw. Shift-click to select both, go to Lens Corrections and check Enable Profile Corrections.

2. Edit the Sky Image

   Select just the sky image. Raise Vibrance, nudge Exposure up, and balance Highlights and Shadows to taste. Add a Graduated Filter from the top down, zero its settings, then lower Exposure slightly and cool the temperature a touch to even out the top of the sky.

3. Edit the Foreground Image

   Select the mountain image and lift the Shadows a little. It needs very little else.

4. Set the Workflow Options

   Click the workflow link at the bottom of the window. Choose Adobe RGB (1998), 16 Bits/Channel, and check Open in Photoshop as Smart Objects. Select both images and click Open Objects.

Combine the Images and Select the Sky

5. Stack the Sky Over the Foreground

   With the Move Tool (V), drag the sky Smart Object into the foreground document and close the original. Lower the sky layer’s opacity temporarily so you can position it: the new sky should fill the frame and its horizon should sit below the tops of the foreground mountains. Return opacity to 100 percent.

6. Select the Original Sky With the Magic Wand

   Hide the new sky layer, select the foreground layer and press W for the Magic Wand. Hold Shift and click several times across the sky. Always select the simpler element; a plain sky is much easier than a jagged mountain range.

7. Load the Selection as a Mask

   Turn the new sky layer back on, select it and click the Add Layer Mask button. The new sky now shows only where the old one was.

8. Clean Up the Mask

   Alt/Option-click the mask thumbnail to view it. Use the Marquee or Lasso tools to select any missed patches and press Shift + Delete to fill with white (reveal sky) or black (reveal mountains). Zoom in and check the entire edge; small peaks the wand skipped can be traced with the Lasso and filled with black.

Refine the Edge With Select and Mask

9. Open Select and Mask

   Click the layer mask and go to Select > Select and Mask. Set the View to On Layers so you can judge the edge against the real composite.

10. Feather, Contrast and Shift Edge

    Add a little Feather to soften the hard wand edge, raise Contrast to keep it defined, and use Shift Edge to pull the mask in or out until the fringe along the ridgeline disappears. Too much feather loses the detail that makes the edge look real, so keep it modest.

11. Output and Repeat if Needed

    Set Output To Layer Mask and click OK. If part of the edge still needs help, run Select and Mask again with small adjustments. This same process works for trees and other complex edges.

Match the Light and Color

The sky lights everything beneath it, so a dark blue sky over a warm, sunlit foreground will never look right. Because both layers are Smart Objects, you can keep returning to Camera Raw until they agree.

12. Brighten and Warm the Sky

    Double-click the sky Smart Object thumbnail to reopen Camera Raw. Raise Exposure, then add Graduated Filters to brighten the lower sky where the sun would be. In the HSL panel lower the saturation of the blues. Warm the Temperature until the clouds pick up reds and yellows that echo the sunlit peaks, then raise Vibrance and Saturation to match the foreground’s intensity. Click OK after each round and judge the composite.

13. Reposition the Sky Independently

    Click the chain icon between the sky layer and its mask to unlink them, then press Ctrl/Cmd + T to move or stretch the sky itself while the mask stays put. Skies allow a fair amount of leeway here.

14. Darken the Top of the Sky

    Back in Camera Raw, add a Graduated Filter from the top with lowered Exposure and Contrast so the upper sky has the same weight and definition as the original, which helps the mountains sit naturally against it.

15. Warm the Mountains to Match

    Double-click the foreground Smart Object, choose the Adjustment Brush, zero its settings, and paint over the peaks and ridges nearest the sky. Raise Temperature and a little Exposure so the warm light from the new sky appears to fall on the land. Repeat on other faces of the mountains as needed. You are effectively painting light.

16. Final Edge Pass

    If the ridgeline still looks slightly cut out, open Select and Mask once more and add a hint of feather. Toggle the sky layer off and on to compare before and after.

Key Takeaways

• Choose a replacement sky shot from a similar location, angle and focal length.
• Open both RAW files as 16-bit Smart Objects so you can revisit Camera Raw at any time.
• Select the simpler element (the sky) with the Magic Wand and load it into a layer mask.
• Refine the ridgeline with Select and Mask using Feather, Contrast and Shift Edge.
• Matching brightness, color temperature and saturation between sky and land is what sells the composite.

Related Tutorials

• Cloud Processing in Photoshop: 4 Easy Selection Wins
• Fix Dull Skies in Photoshop: 4 Easy Steps to a Real Match
• Sky Replacement in Photoshop: 4 Easy Matching Rules