Using the Magnetic Lasso Tool:
1. Open Your Image: Open your portrait image in Photoshop.
2. Select the Magnetic Lasso Tool: Find the Lasso Tool in the toolbar (it looks like a lasso rope). Click and hold on it until the flyout menu appears, then choose the "Magnetic Lasso Tool."
3. Adjust Settings (Important!): Before you start tracing, adjust these settings in the Options Bar at the top:
* Width: This determines how far the tool searches for edges. A good starting point is 10-20 pixels. Increase if your edges are fuzzy, decrease if they're very sharp. Adjust as you go.
* Contrast: This controls how sensitive the tool is to contrast changes. Higher values mean it will stick to edges with high contrast. Start around 10-20%. Adjust based on the image.
* Frequency: This determines how often the tool places anchor points. Higher values (more points) can give you a more precise selection, but also more to edit later. Start with 50-60. Increase if the lasso is drifting away from the edge.
* Tablet Pressure to Size: If you're using a graphics tablet, check this box to control the width with pen pressure.
4. Start Tracing:
* Click once on a clear starting point along the edge of your subject. You don't need to hold down the mouse button.
* Carefully move the cursor along the edge of your subject. The tool will automatically try to "snap" to the edge.
* Correcting Mistakes:
* If the lasso goes off-track, press the Delete or Backspace key to remove the last anchor points.
* If you need to manually place an anchor point, click the mouse button.
* Closing the Selection: When you reach your starting point, move the cursor over the initial anchor point. A small circle will appear next to the cursor. Click to close the selection. Photoshop will highlight the selection.
5. Refine the Selection (Crucial): The Magnetic Lasso is rarely perfect. This is where you'll spend the most time.
* Select and Mask: This is the most powerful option for refining edges, especially around hair. Click the "Select and Mask" button in the Options Bar.
* View Mode: Choose an appropriate view mode (e.g., "Onion Skin," "Overlay," "On Black").
* Global Refinements:
* Smooth: Reduces jagged edges.
* Feather: Blurs the selection edge to blend it in. Use a small value (0.5-2 pixels to start).
* Contrast: Sharpens the selection edge.
* Shift Edge: Moves the selection boundary inward or outward.
* Refine Edge Brush Tool: This tool (in the toolbar on the left) is specifically designed to improve selections around complex areas like hair or fur. Paint along the edges of your subject to refine the selection. It's like telling Photoshop to look harder for the edge in that area.
* Output To: Choose "Selection" to create a selection based on your refined mask, or "New Layer with Layer Mask" for a non-destructive approach. The latter is recommended for flexibility.
* Click "OK"
6. Invert the Selection: You've selected your subject, but you want to blur the background. Go to Select > Inverse (or press Shift+Ctrl+I / Shift+Cmd+I). Now the background is selected.
7. Blur the Background:
* Gaussian Blur: Go to Filter > Blur > Gaussian Blur.
* Adjust the "Radius" slider to control the amount of blur. Start with a small value (e.g., 2-5 pixels) and increase it until you achieve the desired effect. A little goes a long way. Don't overdo it, or it will look artificial.
* Click "OK".
8. Optional: Add a Vignette: A subtle vignette can help draw the eye to the subject.
* Create a new empty layer.
* Use the Elliptical Marquee Tool to create a loose selection encompassing the main portion of your image.
* Invert the selection (Select > Inverse).
* Fill the selection with black (Edit > Fill > Contents: Black).
* Set the layer blending mode to "Multiply."
* Reduce the layer opacity until the vignette is subtle and pleasing.
Important Considerations & Alternatives:
* Non-Destructive Editing is Better: Whenever possible, avoid making permanent changes to your original image. Use layers and masks instead. This allows you to adjust the blur amount and edge refinements later without damaging your original. The "Select and Mask" tool's "Output To: New Layer with Layer Mask" option is perfect for this.
* Hair and Fine Details: The Magnetic Lasso struggles with fine hair or fur. Here are better alternatives:
* Select and Mask (with Refine Edge Brush): As mentioned above, this is the *best* option for complex edges.
* Channels: If your subject has a strong color contrast against the background, you can use the Channels palette to create a selection based on luminance (brightness). This is more advanced, but can be very powerful for hair.
* Pen Tool: The Pen Tool allows you to create precise vector paths, which can then be converted into selections. It's more time-consuming, but offers the most control. This is a good choice for portraits with very clean, sharp edges.
* Focus Area: Photoshop has a "Focus Area" selection tool (Select > Focus Area) that tries to automatically identify the in-focus parts of your image. Sometimes it works well for portraits, but it can be unreliable.
* Blur Types: Gaussian Blur is a common choice, but experiment with other blur filters like "Lens Blur" (Filter > Blur > Lens Blur) for a more realistic depth-of-field effect. Lens Blur allows you to simulate different aperture settings. It can be more resource-intensive than Gaussian Blur.
* Depth Maps for Realistic Blur: For the most realistic results, especially if you have access to a depth map (e.g., from a phone's portrait mode), you can use the Lens Blur filter with the depth map as the "Source." This allows the blur to vary depending on the distance from the camera, creating a more natural-looking bokeh.
* Layer Masks: If you output to a new layer with a layer mask, you can easily adjust the blur amount, refine the edges of the mask (using a brush with black or white), or even paint in or out specific areas of the blur.
* Content Aware Fill: After selecting the background, consider using Content Aware Fill (Edit > Fill > Content-Aware) to remove unwanted objects or distractions in the background *before* applying the blur. This will give you a cleaner final result.
In summary:
1. Open Image and Select Magnetic Lasso.
2. Adjust Magnetic Lasso Settings.
3. Trace the Subject Edge Carefully.
4. Refine with Select and Mask (Especially for Hair).
5. Invert Selection (Select > Inverse).
6. Apply Gaussian Blur (Filter > Blur > Gaussian Blur).
7. Optional: Add a Vignette.
8. Save as a new file (PSD or a flattened image like JPEG).
Don't be afraid to experiment with different techniques and settings. Refining selections is an art in itself, and practice is key to getting good results. The Magnetic Lasso is a good starting point, but be prepared to use other tools and techniques for more complex images. "Select and Mask" with the Refine Edge brush is your best friend for hair!