Mask a Subject

The most common local edit: make the subject stand out from the background. You select the subject with AI, fix the edges if needed, then brighten the subject and calm down the background.

1. Open the Masks panel

Open the photo (Enter) and press M.

2. Select the subject

Click Subject under AI Selections.
Drag a box around the subject, from one corner to the opposite corner. Keep the box snug: include the whole subject (hair, hands, feet) but as little background as possible. This gives a much more accurate result than a single click, which you can still use for quick selections.
A red overlay shows the selection after a second or two.

The first time, the AI model downloads; this takes a moment once.

A person selected with a Subject mask, shown as a red overlay — The red overlay shows what is selected.

Not quite right? Use Grow to expand the selection a little if the edge of hair or clothing is missing, and Feather to soften the edge.

3. Refine with a brush (if needed)

Common misses: hair against a busy background, gaps between arm and body, objects the person is holding.

Hover the mask and click Add New Component (or right-click it).
To remove an area, choose Subtract from Mask → Brush. To add an area, choose Brush.
Set Brush Size with Ctrl+↑ / Ctrl+↓, and Brush Feather around 50 for natural edges.
Paint over the area. Hold Alt to switch to the eraser for a moment.

Zoom in (Space) for precise work.

4. Brighten the subject

Click the mask (not the component) so the adjustments apply to it. Start with:

Slider	Value	Why
Exposure	+0.3	The subject becomes the brightest part.
Contrast	+10	A bit more shape.
Clarity	+10 to +20	Detail in face and clothes. Stay below +25 on skin.
Whites	+10	Small lift on the brightest spots.

Drag the mask's Opacity down if the effect is too strong.

5. Calm down the background

Right-click the mask and choose Duplicate and Invert Mask. You get a new mask that covers everything except the subject, with fresh sliders. Set:

Slider	Value	Why
Exposure	−0.3	Background a little darker.
Saturation	−15	Less competing color.
Clarity	−10	Softer, less distracting details.

6. Compare and name

Press B to compare with the original. Right-click each mask → Rename: "Subject", "Background". You'll thank yourself when you come back to the photo later.

Which mask for which job?

Situation	Best mask
A person, animal or object	Subject
Only skin, eyes, lips or hair	Face (choose the parts)
The sky	Sky
No single clear subject, but a clear foreground	Foreground
Something you can name ("car", "water", "red jacket")	Text
Everything far away	Depth
A gradual change across the frame	Linear
A spotlight on one area	Radial
A specific color, such as a blue sky between leaves	Color
Only the bright or dark parts	Luminance

Combine them: Subject ∩ Luminance (Intersect) selects only the bright parts of the subject; Sky ∩ Linear limits the sky effect to the top of the frame.

Use the same mask on the whole series

Right-click the mask → Copy Mask, go to the next photo, right-click empty space in the Masks panel → Paste Mask. The AI selection is recalculated for the new photo automatically. Or save the masks in a preset with Include Masks.