Target specific areas using shape masks

A shape mask defines an area in the image so that you can apply color corrections either inside or outside that area. For example, you might want to emphasize an object in a shot by darkening the area around the object.

Viewer showing shape mask around an image of car with everything outside of mask darkened

You can add multiple shape masks to define multiple areas, and you can also animate the shapes with keyframes so that they follow an area while a camera pans or an object moves as the clip plays. For information about animating shape masks, see Animate an effect shape mask. For information about working with keyframes, see Video animation overview and Adjust video effects using keyframes.

Add a shape mask

  1. Add a color correction to a clip in the Timeline.

  2. If the Video inspector is not already visible, do one of the following:

    • Choose Window > Show Inspector (or press Command-4).

    • Click the Inspector button in the toolbar.

      Inspector button
  3. Click the Video button at the top of the Inspector pane to open the Video inspector.

    The Video inspector appears with the Color Correction in the Effects section.

  4. In the Effects section of the Video inspector, move the pointer over the effect name and click the Apply Effect Masks button .

    Effects section of Video inspector showing Apply Effect Masks button
  5. In the pop-up menu that appears, choose Add Shape Mask.

    The onscreen controls appear in the Viewer, superimposed over the video image. By default, the shape mask is set to a partially feathered circle in the center of the frame. The Shape Mask parameter appears in the effect’s section of the Video inspector.

  6. Adjust the onscreen controls to specify which part of the video image is affected by the color correction.

    Default shape mask and onscreen controls in Viewer
    • To position the shape: Drag the center.

    • To adjust the shape’s width or height: Drag any of the four handles at the 90-degree points (top, bottom, left, or right) of the inner circle. You can hold down the Shift key while dragging to force all sides to scale proportionally.

    • To control the roundness of the shape: Drag the handle to the left of the inner circle’s top handle.

    • To rotate the shape: Drag the rotation handle (extending from the center).

    • To control the softness of the shape’s edge: Drag the outer circle. Setting the outer circle close to the inner circle creates a hard edge and an abrupt transition to the corrections you apply, and dragging the outer circle away from the inner circle creates a softer edge and a more gradual transition.

    To show or hide the mask’s controls, click the Shape Mask Onscreen Controls button to the right of the shape mask name in the mask list.

  7. To view the mask alpha channel, click View Masks (next to the effect name).

    The mask’s alpha channel appears in the Viewer. White indicates fully opaque mask areas, black indicates areas outside the mask, and levels of gray indicate transparent mask areas.

  8. To adjust the color correction settings for masked area of the image, click the Color Board button in the Video inspector.

  9. Do one of the following:

    • To apply a color correction to the shape area: Click Inside.

      Inside and Outside Mask buttons in Color Board
    • To apply a color correction to everything except the shape area: Click Outside.

    You can make corrections to both the inside and outside areas of the mask—each area effectively has its own complete set of Color Board controls. For example, you could select Inside Mask and enhance the shape’s area, and then select Outside Mask to darken everything else.

  10. Adjust the Color Board controls to create the effect you want.

    For more information about working with the Color Board, see Color correct the whole image.

  11. To add additional shape masks to the correction, repeat steps 4 and 5 above.

    Another default shape appears in the Viewer, and the original shape is dimmed. You can select and continue configuring the original shape by clicking its center.

For information about how masks can interact, see Combine multiple masks on a video effect.

Delete a shape mask

  1. In the Video inspector, select the Shape Mask item you want to delete.

    Color section of Video inspector showing selected Shape Mask item
  2. Press Delete.