1. Open Your Image in Photoshop:
* Go to `File > Open` and select the image you want to edit.
2. Duplicate the Layer (Important!):
* In the Layers panel (usually on the right), right-click on your background layer.
* Choose `Duplicate Layer...` and click `OK`. This protects your original image and allows non-destructive editing. You'll be working on the duplicated layer.
3. Select the Magnetic Lasso Tool:
* Find the Lasso Tool in the Tools panel (usually on the left). It looks like a lasso.
* Click and hold on the Lasso Tool icon until a fly-out menu appears.
* Select the `Magnetic Lasso Tool`.
4. Adjust Magnetic Lasso Tool Settings (Important!):
* Width: This controls how far the lasso "searches" for edges. A smaller width is better for fine details; a larger width is better for high-contrast edges. Start around 5-10 pixels and adjust as needed.
* Contrast: This determines how much contrast is needed for the tool to "stick" to an edge. Higher contrast is good for well-defined edges; lower contrast is good for softer edges. Start around 10-20% and adjust.
* Frequency: This controls how often the tool places anchor points along the selection path. Higher frequency means more anchor points and a potentially more accurate selection (but also more points to adjust). Start around 50-70 and adjust.
5. Create the Selection:
* Start Point: Click near the edge of your subject (the person in the portrait). This creates the initial anchor point.
* Trace the Outline: Slowly move your mouse around the edge of your subject. The Magnetic Lasso Tool will attempt to automatically snap to the edge based on the contrast and width settings.
* Correcting Mistakes: If the lasso snaps to the wrong area, press the `Delete` key (or `Backspace` on some keyboards) to remove the last anchor point. Then, carefully reposition your mouse and continue tracing.
* Completing the Selection: When you reach the starting point, move the mouse cursor over it. A small circle will appear next to the cursor icon, indicating that you can close the selection. Click to complete the selection.
6. Refine the Selection (Crucial! Magnetic Lasso is often imperfect):
* Select and Mask: With the selection active, go to `Select > Select and Mask...`. This opens a dedicated workspace for refining selections.
* View Mode: Choose a view mode that helps you see the selection clearly (e.g., Overlay, On White, On Black).
* Global Refinements:
* Smooth: Increase the `Smooth` slider slightly to soften jagged edges. Don't overdo it.
* Feather: Add a small amount of `Feather` (1-3 pixels) to blend the selection edge more seamlessly. This is important for a natural-looking blur.
* Contrast: Increase the `Contrast` slider slightly to sharpen the edges of the selection. This helps prevent the blur from "bleeding" into the subject.
* Shift Edge: This slider allows you to expand or contract the selection. Experiment to find the best setting. Often a slight contraction (-1 or -2) helps avoid halos.
* Refine Edge Brush Tool (Important!): Use the `Refine Edge Brush Tool` (usually the second tool in the toolbar on the left in Select and Mask) to paint over tricky areas like hair or fur. This tool helps the selection identify fine details and create a more realistic edge. Experiment with the size of the brush.
* Output Settings: Under `Output Settings` at the bottom of the Select and Mask panel:
* `Output To`: Choose `New Layer with Layer Mask`. This creates a new layer containing only the selected subject with a layer mask defining the edges.
* Click `OK`.
7. Select the Background Layer:
* In the Layers panel, click on the *original* duplicated layer (the one *without* the layer mask you just created). This is the layer you will blur.
8. Apply Gaussian Blur:
* Go to `Filter > Blur > Gaussian Blur...`
* Adjust the `Radius` slider to control the amount of blur. A higher radius creates a stronger blur.
* Experiment with the radius until you achieve the desired background blur effect. Consider how much depth of field you want to simulate.
* Click `OK`.
9. Fine-Tune (Optional):
* Opacity: If the blur is too strong, reduce the opacity of the blurred layer in the Layers panel.
* Brush Tool & Layer Mask: If there are areas where the blur is bleeding onto the subject due to imperfections in the initial selection, you can use the Brush Tool with black as the foreground color and paint on the *layer mask* of the subject layer to hide those areas. Use white to reveal the subject if you accidentally painted over it. Use a soft brush for smoother transitions.
Important Considerations and Alternatives:
* Accuracy: The Magnetic Lasso Tool is not the most accurate selection tool, especially with hair or complex edges. You'll likely need significant refinement in the Select and Mask workspace.
* Feathering: A well-feathered selection is crucial for a believable blur. Without it, the edge between the blurred background and the sharp subject will be harsh and unnatural.
* Alternatives:
* Quick Selection Tool/Object Selection Tool: These are often faster and more intuitive for making initial selections, especially in newer versions of Photoshop. You can still refine the selection in Select and Mask.
* Pen Tool: This is the *most* accurate but also the most time-consuming method. It allows you to create precise vector-based selections.
* Channels: For very complex selections (like hair), using channels and luminosity masks can provide the most accurate and natural-looking results. This is an advanced technique.
In summary, while you *can* use the Magnetic Lasso Tool for this task, be prepared for a significant amount of refinement. Consider exploring the Quick Selection Tool, Object Selection Tool, or even the Pen Tool for better results. Experiment with the Select and Mask workspace and layer mask techniques to achieve a convincing background blur.