Professional Technique to Turn a Gray Sky Blue In Photoshop
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Turn a gray sky blue in Photoshop using a channel-based mask, the Dodge and Burn tools, and a Gradient Fill layer, all without an automated sky replacement.
Picture this. It’s the perfect weather for a walk around the city. You’re in a foreign country, and you take a photo of one of its most popular tourist sights with the sky as your background!
But upon viewing the image, you realize the sky is bland. That is exactly what happened on my recent trip to Milan, Italy.
In this tutorial, I’ll be showing you how you can improve your photo and turn a white/grey sky into a blue sky in Photoshop!
If you have the new Photoshop 2021 or newer then you can also try the new automated method to replacing skies in Photoshop!
Key Takeaways
- A Gradient Fill layer lets you recolor an existing sky without importing a new sky photo.
- The Channels panel often builds a cleaner mask than Select Subject when the edges are full of fine detail, like branches or a crane.
- Applying a channel to itself with a Blending Mode like Screen or Linear Burn sharpens a mask before you use it.
- A sky that goes too dark next to a bright building looks fake. Match the sky to the atmospheric perspective already in the photo.
- Stack two layer masks: one for the building, and one that hides everything above it. Paint with white to reveal a darkening effect only where a structure needs it.
- Holding Alt (Windows) or Option (macOS) while dragging the Masking slider in Camera Raw shows exactly which edges get sharpened.
Table of contents
- What You Will Learn
- Requirements
- Keyboard Shortcuts
- Discovering the HSL tab
- Creating a Digital Sky
- Whiten the Sky
- Enhance the Shadows and Highlights
- Make a Selection of the Bright Pixels
- Turn a Gray Sky Blue in Photoshop
- Fixing Small Details
- Fixing Atmospheric Problems
- One Last Tip!
- Frequently Asked Questions
- Conclusion
- Related Links
What You Will Learn
- How to build a sky mask from the Channels panel instead of Select Subject
- How to whiten a sky and blacken a foreground with the Dodge and Burn tools
- How to sharpen a channel mask with Apply Image and blending modes
- How to recolor the sky with a Gradient Fill layer
- How to keep the result believable with atmospheric perspective and Camera Raw
Requirements
Before you start
- Photoshop 2020 (version 21.0 or later) or the current version
Keyboard Shortcuts
| Action | Windows | macOS |
|---|---|---|
| Undo | Ctrl Z | Command Z |
| Select the Zoom tool | Z | Z |
| Increase or decrease brush size | [ or ] | [ or ] |
| Add to a Lasso selection | Shift drag | Shift drag |
| Subtract from a Lasso selection | Alt drag | Option drag |
| Fill with the Background color | Ctrl Backspace | Command Delete |
| Deselect | Ctrl D | Command D |
| Toggle a dialog’s Preview checkbox | P | P |
| Load a channel as a selection | Ctrl click the thumbnail | Command click the thumbnail |
| Duplicate a layer mask onto another layer | Alt drag the mask | Option drag the mask |
| Duplicate and invert a layer mask at once | Alt Shift drag the mask | Option Shift drag the mask |
| Create a black (hide-all) layer mask | Alt click the mask icon | Option click the mask icon |
| Reveal exactly where Sharpening applies | Alt drag the Masking slider | Option drag the Masking slider |
Discovering the HSL tab
Right-click on the layer and select Convert to Smart Object.
Doing this will help you preserve the image’s original characteristics despite all of the filters and adjustments that will be applied to the image. At the same time, allowing you to go back to its original content when needed.
Choose Filter > Camera Raw Filter.
Adjust the Tonality and the Color of the image.
On the HSL tab, you can adjust the Hue, Saturation, and Luminance of each color channel, giving you full control of the colors in your image.
With the Blue slider, adjust it to the left and right to bring out more of the blue and make the sky vibrant.
Tip: If that doesn’t seem to work and your sky is still grey, you can click Cancel at the bottom of the window to undo the change you applied. Instead, you can create a digital sky.
Creating a Digital Sky
The Select Subject tool works perfectly with inanimate objects or human subjects. However, for photos with intricate details, that may not be the best option. Photoshop’s AI-powered selection can make mistakes sometimes, and correcting it will only cost you time.
For a more straightforward solution, create a selection out of it using the Channels panel.
From there, you will see the Red, Green, and Blue channels that make up the RGB image. Click on each channel and see which channel has a stronger contrast between the foreground and the background.
In this example, the Blue channel shows exactly what you need.
Click-and-drag the Blue channel to the New Channel icon to duplicate it.
Whiten the Sky
Next, change the sky into white and transform the rest of the image into black. For this, you can use the Dodge and Burn tools to whiten and blacken the selected pixels.
Use the Dodge tool to whiten the pixels that are part of the sky.
On the Options bar, select the Range to target Highlights.
For the Exposure, set it to 50%.
Paint over the sky while avoiding the larger areas of the Duomo. It’s okay if your brush grazes over the towers.
If you happen to make a mistake, simply press CtrlZ (Windows) or CommandZ (macOS) to undo the recent step.
On the contrary, use the Burn tool to darken the foreground.
On the Options bar, select your Range as Shadows and the Exposure set to 50%. Just as you did for the sky, paint over the Duomo with the Burn tool to make the pixels darker.
Next, select the Lasso tool and use it to freehand a selection around the Duomo.
Set black (#000000) as your Background color, and press CtrlBackspace (Windows) or CommandDelete (macOS) to fill the selection with the background color.
After the selection is filled, you can pressCtrlD (Windows) or CommandD (macOS) to deselect.
Enhance the Shadows and Highlights
Next, use a powerful filter on Photoshop where it allows you to take this channel and apply it to itself using a Blending Mode to enhance the shadows or highlights.
Choose Image > Apply Image.
On the Channel options, select the Blue Copy and set Screen as your Blending Mode, this makes the image brighter and the differences clearer.
Click OK to exit the window.
Next, do the exact same step, but to make the image darker. Choose Image > Apply Image.
Set the Blending Mode to Linear Burn.
Click OK to exit the window.
Click here to learn more about Blending Modes!
To darken all of the details of the Duomo, keep on repeating this process. You can also use the Brush tool, select a smaller brush, and paint the small details with black color.
Make a Selection of the Bright Pixels
Hold the Ctrl (Windows) or Command (macOS) key and click on the Channel thumbnail to load the bright pixels as a selection.
Click on the RGB to select all channels, go back to the Layers panel and from there, create a Gradient Fill Layer.
Turn a Gray Sky Blue in Photoshop
To start selecting the perfect blue sky for your image, simply click on the Gradient Editor.
You can select among the options in the Presets and swap out the colors for your preferred shade of blue.
Feel free to experiment on this part until you find the right color of the sky that fits your image perfectly.
Once you’re happy, click OK to exit the Color Picker and the Gradient Editor window.
On the Gradient Fill window, you can adjust the position of the gradient as well as increase the scale.
Then press OK to apply the changes and exit the window.
Fixing Small Details
If you zoom in on the left part of the image, you’ll see how you may be losing details of the crane because of the applied masks.
To fix this, select Multiply as your Blending Mode to bring back the details.
Fixing Atmospheric Problems
Create a Curves Adjustment Layer and then right-click to reveal the menu, and select Delete Layer Mask.
Hold Alt (Windows) or Option (macOS) while dragging the layer mask to duplicate it onto another layer.
To invert the effect and apply on the Duomo instead, click on the Layer Mask > click on Invert. Now, when you adjust the curves, it only affects the building.
Another Technique:
To start over, click on the Reset icon at the bottom of the Properties window > right-click on the duplicated layer mask > select Delete Layer Mask.
Select the original layer mask, then hold AltShift (Windows) or OptionShift (macOS). Click and drag the layer mask onto another layer to duplicate and invert it at the same time.
Click on the Direct Selection tool so when you hover over the image, you’ll know where the pixels will appear on the curve.
Drag down a point from the middle of the curve and create another point to bring it back up the highlights to avoid making the building very dark.
On the Layers panel, create a group and name it “Atmosphere.”
Drag the Curves adjustment layer into the group and collapse it.
Then, hold Alt (Windows) or Option (macOS) and click on the Layer Mask icon to create a black Layer Mask to hide everything in the group.
Select the Brush tool with white (#ffffff) set as the Foreground color. Then, Brush over parts of the building you want the effect to show.
In the image, selectively paint over the towers on the back of the Duomo to bring out the contrast.
By making this subtle adjustment, the separation between the Duomo and the new color of the sky looks more realistic.
One Last Tip!
Select the Gradient Fill 1 layer > hold Shift > Select the Layer 0 copy > right-click > Convert to Smart Object. This will combine the three layers into one editable Smart Object.
Next, go to Filter > Camera Raw Filter and adjust the Tonal and Color adjustments.
With the available sliders, feel free to experiment on which adjustments can bring the best out of your image.
On the Detail tab, you can increase the Sharpening to bring out more details but the effect can be so subtle that it’s hard to notice.
To see where the Sharpening is applied, go to the Masking slider and hold Alt (Windows) or Option (macOS) while dragging the slider.
The further you adjust the slider to the right, the more it reveals the edges of the image.
At 90, the sky has completely turned black and it has revealed more details of the building. This also means the sharpness of the building will be applied on the edges of the building and none in the sky.
On the HSL Adjustments, you can adjust the blue slider to make the sky more vibrant. Use the orange slider to contrast the color of the building against the sky.
On the fx tab, apply a small amount of Grain to get rid of the very smooth, computer-generated look of the image.
And this is how you turn a white/grey sky into a blue Sky in Photoshop! With this technique, you’ll never have to worry about ruining a great photo of a perfect day!
Frequently Asked Questions
Build a selection from the sky in the Channels panel, then use Dodge and Burn to make the sky pure white and the foreground pure black. Load that channel as a selection and fill it with a blue Gradient Fill layer. The original sky pixels never leave the photo.
Select Subject struggles with fine detail like a crane, tree branches, or building spires. The Channels panel lets you pick whichever red, green, or blue channel already has the strongest contrast between the sky and the foreground. That channel usually produces a cleaner starting mask.
Click through the Red, Green, and Blue channels and use whichever one shows the most contrast between the sky and the subject. In most outdoor photos that is the Blue channel, since skies carry a lot of blue light and most foregrounds do not.
Image > Apply Image lets a channel blend with itself using a Blending Mode. Screen brightens the sky side of the mask, and Multiply or Linear Burn darkens the foreground side. That sharpens the black-and-white split before you load it as a selection.
Compare the sky’s darkness to the atmospheric perspective already in the photo. A distant building can look naturally bright on its own. A sky that is too dark next to it will look fake, so match the two before you commit to a color.
Yes. Put a Curves adjustment layer inside its own layer group, then give that group a black layer mask so it hides everything. Paint with white using the Brush tool to reveal the darkening only where you want it.
Holding Alt (Windows) or Option (macOS) while dragging the Masking slider shows a black-and-white preview. It reveals exactly which edges get sharpened, so you can keep the effect off of a smooth sky.
Conclusion
Turning a gray sky blue in Photoshop comes down to one core skill: a clean mask that isolates the sky from everything else. You can build that mask from the Channels panel, like this tutorial does, or from a simpler tool.
Once that mask is solid, Dodge and Burn, blending modes, and a Gradient Fill layer are just ways to paint in the color you want. The same mask also works for the highlight and shadow moves in Camera Raw that pull the two areas together.
Watch the full video above for every adjustment in real time, and comment on the video if you have a question about your own sky.
Selections and Masking Mastery
Complete course includes 2.5 hours of step-by-step lessons, 6 structured modules, downloadable practice files, and custom Photoshop brushes. Everything you need to master selections and masks in one place.
Keep going
Next, try Photoshop’s automated Sky Replacement tool for a faster way to swap in an entirely new sky.
Related Links
Final Image
Drag the slider to see before and after
