Quick & Easy Sky Replacement Effect in Final Cut Pro (Tutorial)

Final Cut Pro 21/10/2021 4 min read

A popular effect in digital marketing is the incredible sky replacement composition; an image/clip of a person, place, or object is overlaid with a sky background. These stunning compositions are ideal for social media updates and can be used as the base background for typography videos. Today, we’re going to show you this trendy sky replacement effect in Final Cut Pro.

Part 1: Top 3 Tips for Filming for Sky Replacement

The first step in creating these awesome sky replacement compositions is to film your subject or performer. This effect will work with both photos and video clips, so it’s up to you the media you choose. 

1. Choose the Right Angle

The replacement effect works by removing the original background and adding a new one. Choosing the right angle is essential for positioning your camera and performer for the effect to work. Position your camera low to the ground, shooting at an upward angle, so the horizon is hidden; you just want the performer and sky in your shot.

Another possible option is to use a Green Screen, but if you can shoot outside in a similar light condition to your replacement sky, you’ll get a much better result.

2. Clothing Choices

As with recording on Green or Blue Screen, your performers’ clothing choices need to be considered. When using the Keyer Sample Color option, all the selected colors will be removed; if your clothes are the same color as the sky, you’ll end up with a floating head. If you intend to use the masking option, your clothing choices can still help create a defined line between the foreground and background.

3. Use Stock Footage

Of course, you can film sky shots of your own for the replacement, but Stock footage is a fantastic option for your replacement Sky. You can find everything from nighttime milky way timelapse shots to perfectly fluffy clouds floating across a blue sky. Whatsmore, you often customize your stock footage with downloadable LUTs and Light Leaks.

Part 2: Easy Sky Replacement in Final Cut Pro

There are two options for Sky Replacement in Final Cut Pro; using the Keyer or a Mask. Each has its advantages, but generally, the Sample Color option is best used when you’ve used a Green Screen or your background is one block color that contrasts to the rest of your shot.

Option 1: Using the Keyer Effect

  1. Place your clip in the timeline and trim as needed.
  2. In the Effects panel, search for Keyer, add it to your clip.
  3. In the Inspector, click on the Keyer effect dropdown to reveal the settings.
  4. Click on the Sample Color option and draw a box on the screen over the color you want to remove. Pay close attention to the point where your Performer begins to lose definition.
  5. You can add multiple color sample boxes by clicking on the Inspector again.
  6. Next, go to the Fill Holes, Edge Distance, and Split Level settings. Play around with the levels until you’re happy with the result.
  7. Drag your new sky background to the timeline and position it below your Performer layer.
  8. In the Effects Control panel, search for Color Correction and add it to your Performer layer.
  9. In the Inspector, play around with the color board settings to adjust your Performer to match the tone of your Background.

Option 2: Using the Draw Mask Effect

The draw mask effect can be used to create a similar stylized composition, as well as replacing dull skies in landscape shots. The key to straightforward sky masking is to ensure you have a clearly defined line at your horizon; the straighter the lines, the easier it will be to draw the mask.

  1. Place your clip on your timeline and trim as required.
  2. In the Effects panel, search for Draw Mask and add it to your clip.
  3. In the Inspector, ensure the Bezier option is selected in the Shape Type dropdown menu.
  4. In the media viewer, begin drawing the mask around your sky area; you can fine-tune this a little later.
  5. Join the ends of the mask up to create a complete shape.
  6. In the Inspector, check the Invert box and reduce the Fill Opacity to about 75%. You’ll now be able to see the mask in action.
  7. Zoom in to the media viewer using Cmd and + or Ctrl and + on your keyboard.
  8. In the media viewer, drag the small red box to one side so you can see the edge of the mask.
  9. Click on the mask line to access the path points and adjust them to match the horizon.
  10. Double-click on the line to add a new path point, or click on it and hit delete to remove it.
  11. Continue across your horizon, adjusting the mask to match. The more detail you add, the better the result.
  12. When you are happy with your mask, increase the Fill Opacity back to 100%.
  13. Drag your new Background layer to the timeline and position it below the foreground clip.
  14. Select the foreground and in the Inspector, play with the Mask Feather and Fall Off settings to blend the edges.
  15. In the Effects panel, search for Color Correction and add the Color Board effect to your foreground clip. 
  16. Adjust the color settings in the Inspector.

Bonus: Blend Your Scene with LUTs

A LUT file is a preset color style for your clips, and they can be super handy when it comes to blending your composition. While you have added some color correction to your foreground layer, a LUT can be added to your entire composition giving a consistent level of light, color, and grain to your video.

  1. First, choose and download a LUT pack of your choice. We’re using the Film Looks LUT Pack from Motion Array, but they have a huge range to choose from.
  2. Select both layers in the timeline and right-click > New Compound Clip. Give the comp a name and hit OK.
  3. In the Effects panel, search for Custom LUT, and add it to your compound clip.
  4. In the Inspector, go to the LUT dropdown menu and select Choose Custom LUT.
  5. Navigate to your downloaded LUT pack and select it. Hit OK and FCP will add the LUTs.
  6. Once installed, the different color grades can be selected from the dropdown menu.

Pro Tip: Don’t forget that music plays a massive part in creating an atmosphere for your video. Try adding inspiring and awe-inspiring tracks like Motion Array’s Drifting Reflection.

Sky replacement in Final Cut Pro is pretty straightforward, especially when you have considered the process at the filming stage. Whether you’re looking to create an artistic, abstract composition or realistically replace a dull sky in your scene, Final Cut Pro’s keyer and mask tools are fantastic to have in your editing process.