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Masks and Channels in Adobe Photoshop CS6

Article Description

Learn how to create a mask to remove a subject from a background, refine a mask to include complex edges, create a quick mask to make changes to a selected area, edit a mask using the Properties panel, manipulate an image using Puppet Warp, save a selection as an alpha channel, view a mask using the Channels panel, load a channel as a selection, isolate a channel to make specific image changes.

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Refining a mask

Refining a mask

The mask is pretty good, but the Quick Selection tool couldn’t quite capture all of the model’s hair. The mask is also a little choppy around the contours of the shirt and face. You’ll smooth the mask, and then fine-tune the area around the hair.

  1. Choose Window > Properties to open the Properties panel.
  2. If it isn’t already selected, click the mask on Layer 0 in the Layers panel.
  3. In the Properties panel, click Mask Edge. The Refine Mask dialog box opens.
  4. In the View Mode area of the dialog box, click the arrow next to the preview window. Choose On Black from the pop-up menu.
  5. The mask appears against a black background, which makes it easier to see the edge of the white shirt and the face.

  6. In the Adjust Edge area of the dialog box, move the sliders to create a smooth, unfeathered edge along the shirt and face. The optimal settings depend on the selection you created, but they’ll probably be similar to ours. We moved the Smooth slider to 15, Contrast to 40%, and Shift Edge to -8%.
  7. In the Output area of the dialog box, select Decontaminate Colors. Choose New Layer With Layer Mask from the Output To menu.
  8. Select the Zoom tool in the Refine Mask dialog box, and then click the face to zoom in so you can see its edges more clearly.
  9. Select the Refine Radius tool (Image) in the Refine Mask dialog box. Use it to paint out any white background that remains around the lips and the nose. Press the left bracket ([) to decrease the brush size and the right bracket (]) to increase it.
  10. When you’re satisfied with the mask around the face, click OK.
  11. A new layer, named Layer 0 copy, appears in the Layers panel. You’ll use this layer to add the spikes to the mask of the hair.

  12. With Layer 0 copy active, click Mask Edge in the Properties panel to open the Refine Mask dialog box again.
  13. From the View pop-up menu, choose On White. The black hair shows up well against the white matte. If necessary, zoom out or use the Hand tool to reposition the image so that you can see all of the hair.
  14. Select the Refine Radius tool in the Refine Mask dialog box. Press the ] key to increase the size of the brush. (The options bar displays the brush size; we used 300 px at first.) Then, begin brushing along the top of the hair, high enough to include the spikes. Press the [ key to decrease the brush size by about half. Then, paint along the right side of the head, where the hair is a solid color, to pick up any small, fine hairs that protrude.
  15. As you paint, Photoshop refines the mask edge, including the hair, but eliminating most of the background. If you were painting on a layer mask, the background would be included. The Refine Mask feature is good, but it’s not perfect. You’ll clean up any areas of background that are included with the hair.

  16. Select the Erase Refinements tool (Image), hidden behind the Refine Radius tool in the Refine Mask dialog box. Click once or twice in each area where background color shows. When you erase an area, the Refine Mask feature erases similar colors, cleaning up more of the mask for you. Be careful not to erase the refinements you made to the hair edge. You can undo a step or use the Refine Radius tool to restore the edge if necessary.
  17. Select Decontaminate Colors, and move the Amount slider to 85%. Choose New Layer With Layer Mask from the Output menu. Then click OK.
  18. In the Layers panel, make the Magazine Background layer visible. The model appears in front of an orange patterned background.
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