Select Subject uses Adobe Sensei AI to instantly detect and mask the main subject in a photo. It's the fastest way to isolate a person, animal, or object — and apply targeted adjustments to just that subject.
🤖What used to take 10 minutes of manual brush work now takes one click. The AI does the hard work — you focus on the creative decisions.
Navigation
Where to Find Select Subject
1
Open the Develop module — press D
Make sure you're in Develop, not Library. The Masking panel is in the right-side panel group.
2
Open Masking panel — circle icon or Shift+W
Click the circle/mask icon in the right panel toolbar, or press Shift+W. The Masking panel opens showing all available masking tools.
3
Click "Select Subject"
It's the first button in the Masking panel. Click once — Lightroom analyzes the image and builds the mask automatically in 1–2 seconds.
4
Red overlay appears on the subject
The red area is your mask. Every adjustment you make in the mask panel applies only to this red area — the background stays untouched.
⌨️Shortcut to remember: Shift+W opens the Masking panel instantly from anywhere in Develop.
How It Works
Adobe Sensei AI
Adobe Sensei is the AI engine built into Lightroom. For Select Subject, it was trained on millions of photos to recognize people, animals, and objects as subjects.
🔍
Scene Analysis
The AI examines the full image — color, contrast, composition, context — to determine which area is the main subject.
✂️
Pixel-Level Edge Detection
Once identified, Sensei traces the subject's edges at pixel level — including fine hair, fur texture, and complex silhouettes.
💡The mask is non-destructive — nothing is cut out, nothing is permanent. You can refine or delete the mask at any time.
Reading the Mask
The Mask Overlay
Press O to cycle through three overlay modes after a mask is active.
🔴
Red Overlay (default)
Red = the masked area where your adjustments apply. Great for quickly confirming which area is selected at a glance.
OFF
No Overlay
Mask is still active — you just can't see the red. Use this mode when making actual adjustments so the overlay color doesn't confuse your judgment.
B&W
Grayscale View
White = fully masked. Black = unmasked. Gray = partial coverage. Use this to inspect fine edges before committing to adjustments.
👁️Press O to cycle overlay modes. Press Shift+O to change the overlay color (red, green, white, black).
Refinement
Add and Subtract
When the AI misses an area or includes something it shouldn't, fix it with Add or Subtract Brush.
➕
Add to Mask
Click Add → Brush. Paint over areas the AI missed to include them in the mask. Use for missed edges, hands, or accessories.
➖
Subtract from Mask
Click Subtract → Brush. Paint over incorrectly included background areas to remove them from the mask.
🛠️Even in difficult images, Select Subject gets you 80–90% there. The Add/Subtract Brush finishes the job — still far faster than starting from scratch.
What You Can Do
Adjustments on the Subject Only
After Select Subject runs, adjustment sliders appear below the Mask panel. Every slider applies only to the masked subject.
Add sharpness and surface detail to the subject while keeping the background soft. Reduce noise on a subject without softening background detail.
🎯The global Basic panel still applies to the whole image. Mask adjustments are layered on top — subject-only, non-destructive.
Practical Use
Brightening a Backlit Subject
Expose globally for the background, then use Select Subject to independently brighten the person. The effect looks like professional fill lighting.
1
Set global exposure for the background in the Basic panel
Get the sky or environment looking right. The subject will be too dark — that's fine. Fix it next.
2
Shift+W → Select Subject
Run the mask. Verify it covers the full subject in grayscale view. Fix any edges with Add/Subtract Brush.
3
Raise Exposure on the subject mask — +0.5 to +1.5 EV typical
The subject brightens. The background stays exactly where you set it. Add Shadows +30–50 for natural fill without flat contrast.
📸This single technique solves the most common portrait lighting problem — backlit subjects — in under 30 seconds.
Practical Use
Clarity on Subject, Soft Background
🧑
Subject: +Clarity / +Texture
Clarity +15–30 or Texture +20–40 on the subject mask. Skin pores, hair, and fabric get sharper midtone contrast. Portraits look more present and three-dimensional.
🌫️
Background: Unchanged
No Clarity added to the background by the mask. Optionally add –Clarity globally in the Basic panel to push the background further back.
The Portrait Sharpness Stack:
1. Global tonal corrections in Basic panel
2. Subject mask → Exposure +0.3 (slight lift)
3. Subject mask → Texture +25, Clarity +15
4. Global –Clarity –10 (softens background by contrast)
🖼️The subject looks razor sharp and dimensional against a softer background — no blur filter or compositing required.
Limitations
When Select Subject Struggles
🌿
Busy or complex backgrounds
Dense foliage, crowds, or textured walls make it hard for the AI to confidently find the subject's edge. Expect imprecise mask boundaries.
🎨
Similar tones between subject and background
White clothing against a white wall, or black clothing against a dark background — low contrast at the edge confuses the AI.
💇
Fine hair or fur against complex backgrounds
Wispy flyaway hair is difficult. Select Subject handles this better than a manual brush — but inspect the edges carefully in grayscale view.
🎭
Multiple or ambiguous subjects
Two equally prominent people — the AI may select both, one, or split unpredictably. Always check the mask before adjusting.
🛠️In tough cases: let Select Subject get you 80% there, then use Add/Subtract Brush to clean up the edges.
Combining Masks
Subject + Sky — Full Scene Control
Stack multiple masks to control every zone of the image independently. Each mask has its own adjustment sliders.
1
Mask 1 — Select Subject → brighten the person
Exposure +0.5, Texture +20. Applies only to the subject.
2
Mask 2 — Select Sky → control the sky separately (Lesson 18)
Click "Create New Mask" → Select Sky. Apply sky adjustments: Exposure –0.5, Dehaze +15, Temp –10. Applies only to the sky.
3
Global Basic panel — sets the foundation for everything
The global sliders still apply to the whole image. Mask adjustments layer on top. Three independent zones: subject, sky, and everything else.
🎚️Three independent exposure zones in one image — the equivalent of darkroom dodging and burning, done in 30 seconds.
Workflow Tip
Always Check the Mask First
Open a photo in Develop, run Select Subject, and work through this verification checklist. Click each step as you complete it.
Press Shift+W to open Masking panel — click Select Subject
Press O to switch to grayscale overlay — inspect the mask edges
Press Z to zoom to 100% — scan around the subject edge for problems
Fix any missed areas with Add → Brush. Remove any background intrusions with Subtract → Brush
Press O again to turn overlay off — now make your adjustments
Press \ (backslash) to compare before and after the full edit
Your Homework
🎯
Select Subject Challenge
Open a portrait or subject-focused photo and complete all of these steps.
📸 Choose a portrait, wildlife, or pet photo with a clear subject
🎭 Run Select Subject — Shift+W → Select Subject
👁️ Check the mask in grayscale view (O) — fix edges if needed
☀️ Brighten the subject +0.5 EV — verify the background didn't change
🔬 Add +20 Texture to the subject mask only
💬 Share a before/after in the club gallery or comments
Lesson Recap
1
One Click — Shift+W → Select Subject
AI builds a pixel-accurate mask instantly. Check it in grayscale. Refine with Add/Subtract Brush if needed.
2
Every Slider — Subject Only
Exposure, Texture, Clarity, Color — all applied exclusively to the masked subject. Stack masks for full scene control.
3
Check Before You Adjust
Always verify the mask in grayscale (O key) before moving any sliders. Fix first, adjust second. Clean mask = clean result.
Lesson 18 — Lightroom Classic
Masking: Select Sky
The same AI power, now targeting the sky. Independent sky exposure and color control, dramatic sky enhancement, and combining Subject + Sky masks for complete scene management. Every landscape photographer's best new tool.
AI Sky DetectionSky Exposure ControlLandscape Workflow