Masking effect is used to highlight a particular portion of an image or text and mask the other portions.

Video Tutorial:

The above video teaches you how to mask a portion of image or text in Flash.

• First select the "Keyframe" in the default Layer , mentioned as "Layer3" in the above example.
• Simply drag an image from the library to the Stage.
• Add a new layer say, "Layer4", for displaying the spotlight effects and Select the "keyframe" in that Layer .
• Draw a circle on the image using "Oval tool" to mark the masking area.
• Select the circle object using the "Selection Tool".
• Simply right click in "Layer4" to choose option "Mask"
• Again to animate, right click in the same layer "Layer4" to choose "Create Motion Tween".
• At the end point of animation in "Layer4", right click and choose "Insert Keyframe"
• And, at the same point in "Layer3", right click to choose "Insert Frame".
• Select the endpoint of mask animation in "Layer4".
• Now place the masking circle at the position where the masking ends.
• Press "Ctrl+Enter" to view the flash movie.
• We have masked the image or created a spotlight effect to the image, so that only the text is visible in the movie.