Preparation:
1. Open Your Image: Open your portrait image in Photoshop.
2. Duplicate the Layer: Go to Layer > Duplicate Layer (or press Ctrl/Cmd + J). This creates a copy of your original layer, ensuring you can always go back to the original if needed. Name the duplicated layer something like "Subject Selection" for easy identification.
Selection with the Magnetic Lasso Tool:
1. Select the Magnetic Lasso Tool: From the toolbar on the left side of your screen, select the Magnetic Lasso Tool. (It might be hidden behind the standard Lasso Tool or the Polygonal Lasso Tool, so click and hold on the visible tool to reveal the others.)
2. Adjust Tool Settings (Important): Before you start tracing, adjust the Magnetic Lasso Tool settings in the options bar at the top of the screen. These settings are crucial for getting a good selection. Here's what to consider:
* Width: This determines how far the tool looks for an edge. Start with a value between 5 and 10 pixels. Increase it for images with softer edges, and decrease it for images with sharp, well-defined edges. You can change this *while* you're making the selection by using the bracket keys `[` and `]`.
* Contrast: This setting determines how sensitive the tool is to changes in contrast. A higher contrast setting will make the tool stick to more defined edges, while a lower setting will allow it to follow less obvious boundaries. Start with a value around 10-20%. Adjust this as you go, depending on the image.
* Frequency: This setting controls how often the tool places fastening points. Higher frequency creates more points, resulting in a more precise selection, but also potentially a more jagged line. Lower frequency creates fewer points, which can be smoother but less accurate. Start with a value of around 50 and adjust as needed. For very detailed edges, you might need a higher frequency.
* Pen Pressure: If you're using a graphics tablet, you can enable "Pen Pressure" to control the width of the selection with your pen.
3. Start Tracing: Click once on the edge of your subject where you want to start the selection. Then, slowly move the Magnetic Lasso tool along the edge of your subject. The tool will automatically try to "snap" to the edge.
4. Control Points: While the tool tries to snap, it doesn't always get it right.
* Manually Add Points: If the tool is straying or the edge is tricky, click to manually add a fastening point. This forces the tool to stick to that specific location.
* Delete Points: If you add a point in the wrong place, press the Delete or Backspace key to remove the last point.
* Hold Alt/Option: If the magnetic function is giving you trouble, you can temporarily switch to a standard Lasso Tool by holding down the Alt (Windows) or Option (Mac) key. This allows you to draw freehand. Release the key to return to the Magnetic Lasso.
5. Close the Selection: When you reach the point where you started, click to close the selection. Photoshop will connect the last point to the beginning point, completing the selection.
Refining the Selection (Highly Recommended):
The Magnetic Lasso Tool, while helpful, often doesn't create a perfect selection. Here's how to refine it:
1. Select and Mask (or Refine Edge): With the selection active (you'll see marching ants around your subject), go to Select > Select and Mask (in older versions of Photoshop, this might be called Select > Refine Edge).
2. View Mode: In the Select and Mask (or Refine Edge) workspace, choose a view mode that makes it easy to see the selection's edges. "Overlay" (the default red overlay) or "On Black" are often good choices.
3. Refine Edge Brush Tool: Select the Refine Edge Brush Tool (usually the second tool in the toolbar on the left side of the Select and Mask workspace). This brush allows you to paint along the edges of your subject, especially around hair or fur, to improve the selection's accuracy.
4. Paint Along Edges: Paint along the edges of your subject, focusing on areas where the selection is inaccurate or where there are fine details like hair. The Refine Edge Brush Tool will analyze the pixels and attempt to create a more accurate selection. Experiment with the "Radius" setting of the tool to get the best results. A smaller radius is generally better for hard edges, while a larger radius is better for soft edges like hair.
5. Global Refinements (Optional): In the "Global Refinements" section on the right side of the Select and Mask (or Refine Edge) workspace, you can adjust the following:
* Smooth: Reduces irregularities in the selection boundary. Use this sparingly, as too much smoothing can soften the details.
* Feather: Blurs the selection edge slightly. A small amount of feathering (0.5-1 pixel) can often help blend the subject with the background.
* Contrast: Sharpens the selection edge.
* Shift Edge: Moves the selection edge inward or outward. A slightly negative value can help eliminate halos around the subject.
6. Output Settings: In the "Output Settings" section, choose how you want to output the refined selection. The most common options are:
* New Layer with Layer Mask: This is the recommended option. It creates a new layer containing only your subject, with a layer mask that defines the selection. This allows you to easily edit the mask later if needed.
* Layer Mask: Applies the selection as a layer mask to the current layer.
7. Click OK: Click OK to exit the Select and Mask (or Refine Edge) workspace.
Blurring the Background:
1. Select the Background: Now that you have a selection of your subject with a layer mask (if you used "New Layer with Layer Mask"), you need to select the *background*. There are a few ways to do this:
* Invert the Mask: If you have a layer mask, select the mask thumbnail in the Layers panel (make sure the mask is active, not the layer content). Then go to Image > Adjustments > Invert (or press Ctrl/Cmd + I). This inverts the mask, so the background is now selected.
* Select Inverse: If you haven't created a separate layer with a mask, go to Select > Inverse. This will select everything *except* your original selection.
2. Apply the Blur: Go to Filter > Blur > Gaussian Blur.
3. Adjust the Radius: In the Gaussian Blur dialog box, adjust the "Radius" setting to control the amount of blur. Start with a low value (e.g., 2-3 pixels) and gradually increase it until you achieve the desired effect. A higher radius will create a stronger blur. Be careful not to overdo it – too much blur can look unnatural. The right amount of blur will depend on the image size, resolution, and the overall look you're trying to achieve. Use the preview window to see the effect of the blur in real-time.
4. Click OK: Click OK to apply the blur.
Final Touches:
* Adjust Opacity (Optional): You can adjust the opacity of the blurred layer (if you created a separate layer for the blur) to fine-tune the effect. A lower opacity will make the blur more subtle.
* Refine the Mask (If Needed): If you notice any areas where the blur is bleeding onto the subject, or where the selection isn't perfect, you can further refine the layer mask (if you're using one). To do this, select the layer mask thumbnail and use the Brush Tool (with black to hide and white to reveal) to adjust the mask.
Important Considerations and Tips:
* Image Resolution: The effectiveness of this technique depends on the image resolution. Higher resolution images will generally produce better results.
* Edge Definition: The Magnetic Lasso Tool works best on images with clear, well-defined edges. For images with soft edges, you might need to use the Pen Tool for more accurate selections.
* Non-Destructive Editing: Using layer masks is crucial for non-destructive editing. This allows you to adjust the selection and blur without permanently altering the original image.
* Experiment: Don't be afraid to experiment with different settings and techniques. There's no one-size-fits-all approach to image editing.
* Alternative Blur Methods: Besides Gaussian Blur, you can also try other blur filters like "Lens Blur" (which simulates depth of field) or "Field Blur" for more advanced effects. These might give you more realistic results, but can be more computationally intensive.
By following these steps and experimenting with the settings, you can effectively blur the background of your portrait and create a more professional-looking image. Remember to practice and be patient! The more you use these tools, the better you'll become at achieving the desired results.