Activity 5


For spotlight effects and transitions, use a mask layer to create a hole through which underlying layers are visible. A mask item can be a filled shape, a type object, an instance of a graphic symbol, or a movie clip. Group multiple layers under a single mask layer to create sophisticated effects.

To create dynamic effects, animate a mask layer. For a filled shape used as a mask, use shape tweening; for a type object, graphic instance, or movie clip, use motion tweening. When using a movie clip instance as a mask, animate the mask along a motion path.

To create a mask layer, place a mask item on the layer to use as a mask. Instead of having a fill or stroke, the mask item acts as a window that reveals the area of linked layers beneath it. The rest of the mask layer conceals everything except what shows through the mask item. A mask layer can contain only one mask item. A mask layer cannot be inside a button, and you cannot apply a mask to another mask.

Work with mask layers

You can use mask layers to reveal portions of a picture or graphic in the layer below. To create a mask, you specify that a layer is a mask layer, and either draw or place a filled shape on that layer. You can use any filled shape, including groups, text, and symbols, as a mask. The mask layer reveals the area of linked layers beneath the filled shape.

Create a mask layer

  1. Select or create a layer containing the objects to appear inside the mask.
  2. Select Insert > Timeline > Layer to create a new layer above it. A mask layer always masks the layer immediately below it; create the mask layer in the proper place.
  3. Place a filled shape, text, or an instance of a symbol on the mask layer. Flash Professional ignores bitmaps, gradients, transparency, colors, and line styles in a mask layer. Any filled area is completely transparent in the mask; any non-filled area is opaque.
  4. Right-click (Windows) or Control?click (Macintosh) the mask layer’s name in the Timeline, and select Mask. A mask layer icon indicates the mask layer. The layer immediately below it is linked to the mask layer, and its contents show through the filled area on the mask. The masked layer name is indented, and its icon changes to a masked layer icon.
  5. To display the mask effect in Flash Professional, lock the mask layer and the masked layer.


  • Save your work as: firstlastname_activty5.fla
  • Export movie as: firstlastname_activty5.swf

Part 2– Saving, Exporting and Posting your work:

  • Save as: firstlastname_activity5.fla in your Unit 3/Activity 5 folder
  • export as:  firstlastname_activity5.swf in your Unit 3/Activity 5 folder


Teacher Tutorials and Resources:

Animation Unit, Looping backgrounds and masks from Digital Voices on Vimeo.

Animation Unit, Tweening a looping background using multiple layers from Digital Voices on Vimeo.

animation unit, globe activity – focus on the timeline from Digital Voices on Vimeo.

Teacher’s example of gradient colours:

Teacher’s Timeline: