Photoshop Magnetic Lasso Tool, Page 2
Press Q or use the quick mask button on the toolbar to switch into quick mask mode. In quick mask mode, your image is displayed with a ruby overlay that represents the masked area. You'll notice that in quick mask mode, your tool palette only displays white and black for the foreground and background colors. Painting with white takes away from the ruby overlay to subtract from the mask, and painting with black adds to the ruby overlay to add to the mask.
Below you can see where I have painted away the ruby overlay to reveal the stem of the leaf.
I'll continue around the image refining the edges of the selection as needed. Whenever you are zoomed in to an image you can press the keyboard space bar at any time to temporarily activate the hand tool for panning around the image. It should only takes a few minutes to touch up the edges of the selection this way.
Below you can see the image in quick mask mode after refining the selection.
|While I'm still in quick mask mode, I like to apply a half-pixel gaussian blur to the mask just to soften the edge the slightest bit. Any filters you apply in quick mask mode will only effect the mask and not the image itself.|
After applying the gaussian blur, we can switch back into selection mode by pressing Q or using the toolbar toggle button.
Next the selection is inverted (Selection > Invert) and the background is deleted by pressing delete on the keyboard. Make sure your image is on a layer before hitting delete. If the layer palette shows only one layer labeled background, you must promote it to a layer by double clicking on the background in the layers palette.
Here's the final image with a new background. Additional refinements can be made along the edge of the leaf layer using the eraser tool.
I hope you learned that while Photoshop's tools can be a great aid in making selections faster, it still takes a combination of tools for most tasks. While I may have been able to tweak the magnetic lasso tool options to get a perfect selection the first time, I personally found it was much easier to take a few moments to clean up the selection in quick mask mode.
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Some images from Nova Development's Art Explosion 600,000.