Using Masks with Layers

Layer masks allow you to control a layer's level of transparency. While it is easy to control the opacity of a layer globally using the Opacity slider, layer masks are useful when you want to target a particular part of a layer. Use layer masks to hide or reveal portions of the layer beneath. Layer masks are effective for combining multiple images into a single image or for making localized adjustments.

For the types of layer masks - a white layer mask completely covers the layer below it. As you paint on the white layer mask with a black brush, you are brushing "holes" through the mask, allowing you to see through to the layer below. Conversely, a black layer mask is transparent and completely displays the layer below it. As you paint on the black layer mask with a white brush, you are masking the image, covering the layer below.

To Create a Layer Mask:

Do one of the following:

  • In the Layers pane, right-click the layer you want to add a layer mask to and select Set Mask White or Set Mask Black.
  • Go to Layer | Mask | Set Mask White or Set Mask Black.
  • At the bottom of the Layers pane, press the Add layer mask button.

The layer mask will appear as a white or black box in the Layers pane next to the thumbnail of the image on the layer you selected. To perform actions to the layer mask, you must select it in the Layers pane. You can alter the opacity of the layer mask by dragging the Opacity slider at the top of the Layers pane. You can apply any Edit mode adjustment to the layer mask by selecting it and entering the tool.

Selected white layer mask

Selected black layer mask

To Disable a Mask:

You can disable a mask without deleting it. You can even disable it, save your layers as a .acdc file and exit Edit mode, then reopen it in Edit mode at a later date and enable your mask again.

  1. Select the mask in the Layers pane.
  2. Do one of the following:
    • Right-click on the mask and choose Disable mask from the context menu.
    • In the Layers pane, press the Disable mask button.
    • Choose Layer | Mask | Disable Mask.
    • Press Ctrl + Shift + M.

To Enable a Mask:

  1. Select the mask in the Layers pane.
  2. Do one of the following:
    • Right-click on the mask and choose Enable mask from the context menu.
    • In the Layers pane, press the Enable mask button.
    • Choose Layer | Mask | Enable Mask.
    • Press Ctrl + Shift + M.

To Use the Mask Preview Option:

When a mask is applied to a selected layer, you can quickly toggle a preview by pressing and holding ] or clicking and holding the "Mask Preview" button at the bottom left of the view window.

Mask Properties

You can adjust the properties of each layer mask on each layer individually using the Mask Properties panel. The adjustments you make are non-destructive, meaning that you can adjust them at any time throughout the editing process.

To Access the Mask Properties Panel:

Select the mask in the Layers pane. The Mask Properties will appear at the bottom of the pane, above Adjustment Layers.

You can make the following adjustments to your layer mask:

Feathering

You can non-destructively feather your mask to avoid sharp edges or a stark contrast between the mask and the layer. Move the slider to blur the edges of the mask.

Invert

You can non-destructively invert your mask. This will turn a white mask black, and a black mask white.

Displaying a Mask Overlay:

You can make your mask easier to see by checking the Show Overlay checkbox in the Mask Properties panel.

To Customize the Mask Overlay:

  1. Right-click on the mask in the Layers pane and choose Mask Overlay Options... from the context menu.
  2. In the Mask Overlay Options dialog, select one of the following overlay options:

    3. Mask Highlighted

    This option highlights your mask in the color of your choosing. Select a color from the drop-down menu. You can customize the transparency of the mask overlay by using the Opacity slider.

    Mask Exposed

    This option highlights the non-masked areas of your layer in the color of your choosing. Select a color from the drop-down menu. You can customize the transparency of the unmasked area by using the Opacity slider.
  3. Press OK.

The mask overlay is only visible when the layer is selected.

To Edit a Layer Mask:

Select the layer mask in the Layers pane, then choose any adjustment, or drawing or selection tool.

Mask Flexibility

You can create or modify selections from masks.

To Create a Layer Mask From a Selection:

You can make a layer mask from a selection.

  1. Make a selection.
  2. Go to Layer | Mask | From Selection.

Or:

  1. Make a selection.
  2. Press the Add layer mask button. Or add any adjustment layer by selecting one of the icons from the bottom of the Layers pane. A mask will automatically be made from the selection.

Or:

  1. Make a selection.
  2. Right-click the layer and choose Mask From Selection from the context menu.

To Add a Mask to a Selection:

  1. With the mask selected in the Layers pane, make a selection.
  2. Right-click the mask and choose Add Mask To Selection.

To Subtract a Mask from a Selection:

  1. With the mask selected in the Layers pane, make a selection.
  2. Right-click the mask and choose Subtract Mask From Selection.

To Select the Area Common to the Mask and the Selection:

  1. With the mask selected in the Layers pane, make a selection.
  2. Right-click the mask and choose Intersect Mask With Selection.

To Delete Selected Mask Pixels:

See Using Selections.

Creating Layer Masks From Specific Colors and Tones

You can create masks from specific targeted colors and/or tones—and even skin tones.

To Create a Layer Mask by Targeting Colors or Tones:

  1. Select your layer and set a white or black mask, as described above.
  2. Right-click the mask and choose Pixel Targeting... from the context menu.
  3. On the Pixel Targeting panel, configure the settings as described below.
  4. Press OK. The mask will be created from the targeted colors and/or tones.

The Pixel Targeting Panel

The Pixel Targeting panel consists of four sections: Targeted Tones, Targeted Colors, Skin Targeting, and the Target Mask.

Target Mask

The Target Mask allows you to see the areas in the image that are targeted by displaying them in white. When no pixels are targeted, the Target Mask will appear completely black. Conversely, when all pixels are targeted, as is the case before any sliders have been altered on the Pixel Targeting panel, the entire Target Mask will appear completely white.

Targeted Tones

The Targeted Tones sliders allow you to target tones of brightness for the mask. To target one or more tones, you may find it easiest to press the Min button under the Targeted Tones section. This deselects all tones, and you can then select specific tones to target for the mask by moving their sliders up between 0 and 100, depending on your desired intensity.

Targeted Colors

The Targeted Colors sliders allow you to target specific colors for the mask. To target one or more colors, you may find it easiest to press the Min button under the Targeted Colors section. This deselects all colors, and you can then select specific colors to target for the mask by moving their sliders up between 0 and 100, depending on your desired intensity.

Skin Targeting

The Target Skin slider allows you to specifically target skin tones for the mask. To target skin tones, move the slider to the right between 0 and 100, depending on your desired intensity.

When you move the Skin Targeting slider, all other colors (except for skin tones), are excluded. You cannot then alter the green color slider, for instance.

To exclude skin tones from your mask, move the slider to the left between 0 and -100.

Creating Layer Masks From Images

You can copy color images and paste them as grayscale (luminance) masks on other layers, including adjustment layers.

To Create a Mask from an Image:

  1. Do one of the following:
    • Right-click an image in the Layers pane and choose Copy from the context menu.
    • With an image selected in the Layers pane, choose Edit | Copy.
  2. Select a layer in the Layers pane and do one of the following:
    • Right-click the layer and choose Paste as Mask from the context menu.
    • Choose Edit | Paste as Mask.
    • Choose Layer | Mask | Paste as Mask.

See also: