Topics Covered in This Lightroom Tutorial:
The Adjustment Brush Tool, Adjusting Exposure & Saturation, Viewing Masks, Deleting Adjustment Brush Masks
Exercise Preview

What You'll Accomplish in This Exercise
Darken the Sky
Use the Adjustment Brush with exposure settings to selectively darken an overexposed sky while preserving building and tree details
Desaturate Flowers
Apply saturation adjustments to tone down bright purple flowers using targeted brush strokes
Manage Masks
Learn to view, modify, and delete adjustment masks to refine your editing results
Exercise Overview
In this exercise, you'll master the Adjustment Brush tool—one of Lightroom's most powerful precision editing instruments. This tool enables you to apply targeted corrections to specific areas of your image without affecting the entire photograph. You'll learn to selectively darken an overexposed sky and desaturate vibrant flowers, demonstrating how professional photographers achieve balanced, compelling compositions through selective adjustments rather than global corrections.
Pre-Exercise Setup Checklist
Ensures you have the correct sample images for following along
This specific image provides ideal subjects for exposure and saturation adjustments
Optimal viewing setup for precise brush work and mask visualization
Familiarize yourself with tool location for efficient workflow
The Adjustment Brush Tool
- If you have not imported the photos that were imported in Exercise 2E:
- Go into the Library module.
- At the bottom left of the screen, click Import.
- In the dialog box that appears, on the left under Source, navigate to Desktop > Class Files > Lightroom Class and select the Develop folder.
- At the top, above the photos, make sure Add is selected (highlighted).
- On the bottom right, click Import.
In the Library module, select the Hampton Court Palace & violets photo (_CAS4948).
Press D to go into the Develop module.
In the Navigator panel, click on FIT if it is not already highlighted.
Under the Histogram panel, click the Adjustment Brush tool
.- In the panel that appears:
- From the Effect menu, select Exposure if it's not already selected.
- Drag the Exposure slider to around − 1.00.
- In the Brush section under Flow, check Auto Mask.
Press the right bracket key
]a few times to increase the brush size.NOTE: The left bracket key
[will decrease the brush size. These keyboard shortcuts are essential for maintaining workflow efficiency during detailed editing sessions.Brush the entire sky (try to avoid brushing the buildings and trees, though it won't cause much damage due to Auto Mask protection).
When finished, click the Adjustment Brush tool
again to deselect it.Click the Adjustment Brush tool
to select it again.On the photo, locate the circle
, which corresponds to the sky's mask. These mask pins are visual anchors that allow you to return to and modify specific adjustments at any time.Click on this circle
to reveal the mask.NOTE: A black dot will appear inside the circle
to show it's activatedHover over that circle for a few moments, and the mask will be indicated by the color red (appears pink/light red). This visualization helps you verify the exact areas affected by your adjustment.
Next to Exposure, drag the slider to − 3.00. Notice how this dramatic change affects only the masked sky area, leaving the rest of the image untouched.
If you've missed some spots, use the Adjustment Brush tool
to brush them now.If you've accidentally brushed too much, press Opt (Mac) or ALT (Windows) and brush over those areas to subtract from the mask. This erase function is crucial for precision work around complex edges.
Notice that some buildings and trees have a slight halo where the sky meets them. This common issue occurs when adjustments are too aggressive near high-contrast edges. We need to tone down the exposure.
In the right side panel, set the Exposure to − 1.60. This demonstrates the non-destructive nature of Lightroom's adjustments—you can always refine your edits.
Click the Adjustment Brush tool
to deselect it.At the bottom of the screen, click the Before & After icon
to examine your work. This comparison view is essential for evaluating the effectiveness of your adjustments.At the bottom of the screen, click the Loupe View icon
.
Now that you've mastered selective exposure adjustments, let's explore how the Adjustment Brush can control color saturation with surgical precision.
Use the right bracket key ] to increase brush size and left bracket key [ to decrease it. Press O to toggle mask visibility while brushing for better precision.
Brush Controls: Auto Mask vs Manual
| Feature | Auto Mask On | Auto Mask Off |
|---|---|---|
| Edge Detection | Automatic boundary detection | Manual brush control |
| Precision | High accuracy on defined edges | User-dependent accuracy |
| Speed | Faster for complex subjects | Faster for simple areas |
| Best For | Sky, water, uniform areas | Creative effects, soft transitions |
Adjusting Saturation Via Adjustment Brush
Let's decrease the saturation of the bright purple flowers to create a more balanced composition where no single element overwhelms the viewer's attention.
Click the Adjustment Brush tool
.In the panel that appears, from the Effect menu, select Saturation. This preset automatically configures the tool for color intensity adjustments.
Below that, drag the Saturation slider left to − 20. This moderate reduction will tone down the flowers without making them appear lifeless.
Press O to show the red mask color as you brush. This overlay mode allows you to see exactly where you're applying the effect in real-time.
Brush some of the flowers. Focus on the most vibrant blooms first to gauge the effect's impact.
Press the O key again to hide the mask and to see the flowers desaturated. This toggle technique helps you evaluate your work without visual distraction.
Press O again to reveal the mask.
Brush the rest of the flowers to achieve consistent saturation across all the blooms.
Press O to see the changes. Notice how the reduced saturation creates better visual balance between the architectural elements and natural features.
Understanding how to remove adjustments is just as important as knowing how to apply them. Let's explore mask deletion techniques.
Exposure Adjustment Values Used
Hold Option (Mac) or Alt (Windows) while brushing to subtract from your mask. This eraser mode helps fix overspray and refine mask edges without starting over.
Deleting Adjustment Brush Masks
To get rid of one of the adjustment masks that you brushed onto the photo, click on the circle corresponding to the sky's reduced exposure to select its mask. The selected mask pin will display the black dot indicator.
Press Delete on your keyboard to delete it. Notice how the sky immediately returns to its original exposure value.
- Delete all the remaining masks:
- Click on the circle
on the flowers. - Make sure it now has a black dot
inside it. - Press Delete to delete it.
We've now reverted to the original photo, demonstrating the completely non-destructive nature of Lightroom's editing workflow.
As you've discovered in this exercise, the Adjustment Brush tool is indispensable for professional photo editing. It enables precise, reversible adjustments that would be impossible to achieve with global corrections alone. This selective editing capability is what separates amateur snapshots from polished, professional images. Master this tool, and you'll have the power to guide your viewer's eye exactly where you want it to go while maintaining complete creative control over every pixel in your composition.
- Click on the circle
Non-Destructive Editing Benefits
Mask Management Workflow
Create Adjustment
Apply brush with desired effect settings
Refine Mask
Add or subtract areas using Option/Alt modifier
Adjust Settings
Fine-tune effect strength on existing mask
Delete if Needed
Select mask circle and press Delete key