Following complex outlines would be tricky without the Refine Edge tool

When youíre layering one image on top of another, itís often difficult to make a clean selection around the subject. There are nearly always stray pixels of a different tone around object outlines, for example, and these are an unavoidable by-product of the way digital camera images are captured and processed.

When you use a selection tool like the Magic Wand, or the newer and more sophisticated Quick Selection tool, these pixels are left out, so objects have a narrow "halo" just one or two pixels wide, along the edge.
BEFORE: Dividing selections from backgrounds can be a tricky business.

AFTER: Fortunately the Refine Edge tool can nip such problems in the bud.
One way of getting rid of these is to modify the selection once youíve created it. You can do this by "expanding" or "contracting" the selection by a set number of pixels. Youíll find these options on the Select menu. The problem is that you have to try to predict the size of the adjustments you make, because you wonít see the result until you use the selection to cut or mask parts of the layer.

Selections can also be too "hard" Ė the edges of your objects are very sharply defined, where the fine detail in the photo is just a bit softer. These hard edges look artificial, so you would use the Feather command, again on the Select menu, to soften them to about the same degree. Again, though, you have to estimate the amount and wait to see how the result looks when you apply it Ė and if itís not quite right, you have to backtrack using the History palette and re-edit your selection.

Thatís what the Refine Edge option in Elements is designed to solve, and with the introduction of layer masks in Elements 9, you can apply it to masks, too. It enables you to expand, contract and feather masks in an interactive dialog that previews the result. You still need a little judgement and experience to choose the right refinements, but itís a whole lot easier when you can see the outcome "live" as you work.