Social Media Design: How to Use Photoshop's Quick Selection and Refine Edge Tools - dummies

Social Media Design: How to Use Photoshop’s Quick Selection and Refine Edge Tools

By Janine Warner, David LaFontaine

Photoshop offers all kinds of tools to help you prepare an image for your social media site. Think of the Quick Selection tool as having the computer act a little like a more coordinated older sibling, helping their kid brother cut only the sports hero they idolize out of the newspaper.

Photoshop tries to guess what you’re trying to isolate from the rest of the image, and draws a border between the subject and the background. Photoshop Elements also sports this tool, although some users claim that the full version of Photoshop is much more precise in its selection. GIMP has a Foreground Select and Fuzzy Select tool that together come close to emulating the functionality of Quick Selection.

The Quick Selection tool works by applying sophisticated analytics to the image, looking for similar textures in an image, and interpolating the difference between these areas and other areas. For example, it looks for things like the difference between stiff, bristly hair on a horse’s back, and the patchy, mottled appearance of a cloudy sky to figure out where the border between the horse and the sky should be drawn.

[Credit: cw istockphoto.com/KarSol]
Credit: cw istockphoto.com/KarSol
  1. With an image open in Photoshop, choose Layer→Duplicate Layer or press Ctrl+J (on a Mac, cmd+J).

  2. Click and hold on the Magic Wand tool to bring up its submenu. Choose the Quick Selection tool.

    It looks like a paintbrush with a dotted circle around the end, and its keyboard shortcut is W.

    The mouse pointer should change to a circle with a crosshairs in the middle.

  3. Click and hold the left mouse button on the subject in your image and start carefully dragging it around the perimeter of the subject in your image.

    Photoshop will start drawing dotted lines over what it thinks the borders of your subject should be.

    [Credit: cw istockphoto.com/KarSol]
    Credit: cw istockphoto.com/KarSol

    When you’re making your selection, pretend that you’re painting with your mouse cursor over the subject in your image. Use short strokes and release the mouse button frequently. That way, if Photoshop gets a little over enthusiastic when selecting pixels in your image, you can undo the last small selection by pressing Ctrl+Z (on a Mac, cmd+Z) while still retaining the careful selection work that you’ve done so far.

  4. Hold down the Alt (Option) key, and click and drag to deselect areas that aren’t part of your subject and that you don’t want to include.

    You can also click the Add to Selection or Subtract from Selection buttons beneath the main menu. These buttons look like the Quick Selection tool but with a plus or minus button added, respectively.

    You can see that Photoshop included the white area under the arm of the lizard, on the left side. When you hold down the Alt (Option) key, the plus symbol inside the Quick Selection pointer toggles to a minus sign. That means that everything you now click will be subtracted from the selection.

    Alternate between using the Add to Selection and Subtract from Selection settings to get as close as you can to the edge of the subject you are trying to extract.

  5. When you have the subject in your image selected as well as you feel comfortable with, click the Refine Edge button below the main menu bar.

    The Refine Edge dialog box opens along with a new window showing your selection against a solid background. You can choose black, white, or a silhouette. Choose the option that best helps you see the contrast between the selection and the background.

    Stray pixels remain near the snout of the lizard, as well as under the chin, and stray lines are coming off the arms. If the selection is too rough and there are too many stray pixels (or big missing pieces from your subject) — like our example — click Cancel and return to using the Quick Selection tool to further refine your extraction.

  6. Refine the edge.

    1. Click the Refine Radius Tool in the Refine Edge dialog box (the paintbrush squishing down on a dotted line, on the left edge).

      The mouse pointer changes to the circle with a plus sign inside it.

    2. Paint over the edges of your subject where Photoshop hasn’t quite gotten the dividing line between your subject and the background correct.

      As you click and drag over the outlines of your subject, you will see the background of the photo show through. When you release the mouse button, Photoshop will attempt to refine the edge even further.

      [Credit: cw istockphoto.com/KarSol]
      Credit: cw istockphoto.com/KarSol

    If you overdo this, and your image starts to look faded-out and vague, just click the Cancel button and start again.

  7. To further refine the edge, still in the Refine Edge dialog box, adjust the sliders for Smooth, Feather, and Contrast.

    • Smooth creates a more clean, sinuous line in areas where the Quick Selection tool might have left jagged edges.

    • Feather softens the border between your subject and background.

    • Contrast makes the edge between your subject and the background more clearly defined.

    Play around a bit with the sliders to get an edge you’re satisfied with, finding a balance between a smooth (but somewhat ill-defined) and a sharp (but rough and artificial-looking) edge.

  8. When you’re satisfied with your selection, choose the appropriate Output To option and then click OK.

    The choice you should make depends on your expertise with Photoshop and Layer Masks. If you’re a beginner and don’t know much about layer masks, just choose New Layer. To create an entirely new image file, choose New Document.

    Layer masks are handy if you want to continue to work with the underlying image, but they can be hard for a beginner to grasp.

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