In Photoshop Elements 11, you can fine-tune your selection using the Refine Edge (select a portion of an image, right-click the selection, and choose Refine Edge from the context menu) dialog box. You can also open the Refine Edge dialog by choosing Select > Refine Edge.
To open the Refine Edge dialog on a Mac, select a portion of an image, Control-click the selection, and choose Refine Edge.
View Mode. From the View pop-out menu, choose a view mode for your selection. Press F to cycle through the modes
Show Radius. Displays the radius of the edge refinement.
Refine Radius and Erase Refinements tools. Precisely adjust the border area in which edge refinement occurs. To quickly toggle from one tool to the other, press E. To change the brush size, press the bracket keys. Note: Brush over soft areas such as hair or fur, to add fine details to the selection.
Smart Radius. Automatically adjusts the radius for hard and soft edges found in the border region. Deselect this option if the border is uniformly hard- or soft-edged, or if you want to control the Radius setting and refinement brushes more precisely.
Radius. Determines the size of the selection border in which edge refinement occurs. Use a small radius for sharp edges, and a large one for softer edges.
Smooth. Reduces irregular areas (“hills and valleys”) in the selection border to create a smoother outline.
Feather. Blurs the transition between the selection and surrounding pixels.
Contrast. When increased, soft-edged transitions along the selection border become more abrupt.Typically, the Smart Radius option and refinement tools are more effective.
Shift Edge. Moves soft-edged borders inward with negative values or outward with positive ones. Shifting these borders inward can help remove unwanted background colors from selection edges.
Decontaminate Colors. Replaces color fringes with the color of fully selected pixels nearby. The strength of color replacement is proportionate to the softness of selection edges.
Important: Because this option changes pixel color, it requires output to a new layer or document. Retain the original layer so you can revert back to it if needed. (To easily see changes in pixel color, choose Reveal Layer for the View Mode.)
Amount. Changes the level of decontamination and fringe replacement.
Output To. Determines whether the refined selection becomes a selection or mask on the current layer, or produces a new layer or document.