How to Blur a Portrait Background

Step 1: Duplicate the layer Ctrl + J

In the Layers panel, select the original layer (usually Background) and press Ctrl + J (⌘ + J on Mac) to create Background copy. Everything that follows happens on that copy, so the original file is never damaged.

Step 2: Zoom in and trace the path with the Pen tool P

1. Press P (or click the Pen icon in the toolbar) to select the Pen tool.

2. On the left of the toolbar, switch the mode to either Shape or Path — Path is the better choice here.

3. Use the scroll wheel or the Zoom tool (Z) to get to 150%~200%, so you can place anchors precisely along the outline of the subject and the chair.

4. Click around the subject's edge in order to build a closed path (double-click the last anchor to close it). If a segment comes out lumpy, refine it afterwards with the Convert Point tool.

• Click and drag to create a Bézier anchor in one go;
• If you do not want a curve, a single click produces a straight segment;
• Hold Alt (Option) to move the two handles of an anchor independently.

Step 3: Switch to the Direct Selection tool A

Once the path is closed, press A (or click the Direct Selection tool in the toolbar). You can now click individual anchors and nudge them until the path hugs the subject's outline.

Step 4: Turn the path into a selection

1. In the Paths panel (Window → Paths), right-click the path you just made to open the context menu.

2. Choose “Make Selection” (shortcut Enter), tick Feather in the dialog and set it to 1 pixel, then click OK.

The path becomes a marching-ants selection with a slight feather already on the edge, which lets the blur blend in naturally later.

Step 5: Apply the Lens Blur filter

With the selection still active, go to Filter → Blur → Lens Blur (Filter → Blur → Lens Blur).

In the Lens Blur dialog, these are the settings that matter:

• Radius: how strong the blur is. 8‑15 pixels is usually enough; scale it to the image.
• Shape: leave it at the default, Circular.
• Feather: raise it if you want a softer transition, but the selection already carries 1 pixel of feather, so 0 is right most of the time.

Click OK and the background is blurred as a whole.

Step 6: Refine the details (select and blur again)

Lens Blur softens the background as a whole, but areas such as strands of hair or fine fabric folds can be left looking only partly blurred. Select those spots one at a time with the Polygonal Lasso and run Lens Blur again to deepen them locally.

1. Choose the Polygonal Lasso tool (L) and set Feather to 1 pixel in the options bar.
2. Click clockwise or anticlockwise around each under-blurred area (hair tips, the edge of a collar) to close a selection.
3. Repeat Step 5: open Lens Blur again, this time with a smaller Radius (2‑4 pixels), to blur the detail lightly.

When every detail is done, press Ctrl + D (or ⌘ + D) to deselect.

• Soft edge around the subject: check the feather value in Make Selection. If it is too large, rebuild the selection at 0 or 0.5 pixels.
• Uneven background blur: use Gaussian Blur (Filter → Blur → Gaussian Blur) as a fallback — blur broadly first, then refine with Lens Blur.
• Hair detail lost: in the Lens Blur dialog, adjust Blade Curvature, or lower the sharpening on the detail tab.