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Use opacity masks to create transparency



You use an opacity mask and a masking object to alter the transparency of artwork. The opacity mask (also referred to as masked artwork) provides the shape through which other objects show. The masking object defines which areas are transparent and the degree of transparency. You can use any colored object or raster image as the masking object. Illustrator uses the grayscale equivalents of the colors in the masking object for the opacity levels in the mask. Where the opacity mask is white, the artwork is fully visible. Where the opacity mask is black, the artwork is hidden. Shades of gray in the mask result in varying degrees of transparency in the artwork.

Creating an opacity mask

A.
Underlying objects

B.
Opacity mask artwork

C.
Masking object filled with black-to-white gradient

D.
C moved over the area of B and masking B

When you create the opacity mask, a thumbnail of the masking object appears in the Transparency panel to the right of the thumbnail of the masked artwork. (If these thumbnails aren’t visible, choose Show Thumbnails from the panel menu.) By default, the masked artwork and the masking object are linked (as shown by a link between the thumbnails in the panel). When you move the masked artwork, the masking object moves along with it. However, when you move a masking object, the masked artwork doesn’t move. You can unlink the mask in the Transparency panel to lock the mask in place and move the masked artwork independently of it.

Transparency panel displays opacity mask thumbnails: left thumbnail represents the opacity mask, right thumbnail represents masking objects

You can move masks between Photoshop and Illustrator. Opacity masks in Illustrator convert to layer masks in Photoshop, and vice versa.

Note: You cannot enter isolation mode when working in mask-editing mode, or vice versa.

For a video on working with opacity masks, see www.adobe.com/go/vid0056.

Create an opacity mask

  1. Select a single object or group, or target a layer in the Layers panel.
  2. Open the Transparency panel and, if necessary, choose Show Options from the panel menu to see the thumbnail images.
  3. Double-click directly to the right of the thumbnail in the Transparency panel.

    An empty mask is created and Illustrator automatically enters mask-editing mode

  4. Use the drawing tools to draw a mask shape.
  5. Click the masked artwork’s thumbnail (left thumbnail) in the Transparency panel to exit mask-editing mode.
Note: The Clip option sets the mask background to black. Therefore, black objects, such as black type, used to create an opacity mask with the Clip option selected will not be visible. To see the objects, use a different color or deselect the Clip option.

Convert an existing object into an opacity mask

 Select at least two objects or groups, and choose Make Opacity Mask from the Transparency panel menu. The topmost selected object or group is used as the mask.

Edit a masking object

You can edit a masking object to change the shape or transparency of the mask.

  1. Click the masking object’s thumbnail (right thumbnail) in the Transparency panel.
  2. Alt‑click (Windows) or Option-click (Mac OS) the mask thumbnail to hide all other artwork in the document window. (If the thumbnails aren’t visible, choose Show Thumbnails from the panel menu.)
  3. Use any of the Illustrator editing tools and techniques to edit the mask.
  4. Click the masked artwork’s thumbnail (left thumbnail) in the Transparency panel to exit mask-editing mode.

Unlink or relink an opacity mask

  • To unlink a mask, target the masked artwork in the Layers panel, and then click the link symbol  between the thumbnails in the Transparency panel. Alternatively, select Unlink Opacity Mask from the Transparency panel menu.

    The masking object is locked in position and size, and the masked objects can be moved and resized independently of the mask.

  • To relink a mask, target the masked artwork in the Layers panel, and then click the area between the thumbnails in the Transparency panel. Alternatively, select Link Opacity Mask from the Transparency panel menu.

Deactivate or reactivate an opacity mask

You can deactivate a mask to remove the transparency it creates.

  • To deactivate a mask, target the masked artwork in the Layers panel, and then Shift-click the masking object’s thumbnail (right thumbnail) in the Transparency panel. Alternatively, select Disable Opacity Mask from the Transparency panel menu. When the opacity mask is deactivated, a red x appears over the mask thumbnail in the Transparency panel.
  • To reactivate a mask, target the masked artwork in the Layers panel, and then Shift-click the masking object’s thumbnail in the Transparency panel. Alternatively, select Enable Opacity Mask from the Transparency panel menu.

Remove an opacity mask

 Target the masked artwork in the Layers panel, and then select Release Opacity Mask from the Transparency panel menu.

The masking object reappears on top of the objects that were masked.

Clip or invert an opacity mask

  1. Target the masked artwork in the Layers panel.
  2. Select either of the following options in the Transparency panel:
    Clip
    Gives the mask a black background which crops the masked artwork to the boundaries of the masking object. Deselect the Clip option to turn off the clipping behavior. To select clipping for new opacity masks by default, select New Opacity Masks Are Clipping from the Transparency panel menu.

    Invert Mask
    Reverses the luminosity values of the masking object, which reverses the opacity of the masked artwork. For example, areas that are 90% transparent become 10% transparent after the mask is inverted. Deselect the Invert Mask option to return the mask to the original state. To invert all masks by default, select New Opacity Masks Are Inverted from the Transparency panel menu.

    If these options aren’t visible, select Show Options from the panel menu.