Are you planning your next big video project or lecture? Would you like to replace the background with an image of an object, person, location, or perhaps a PowerPoint slide (saved as an image file)? Well, the first thing you need is access to a green screen and light kit. Lucky for you, TLT has both! We even have an iPad teleprompter–all available for faculty use, every Tuesday from 1-4 PM, in J.C. Long 317 – or – by appointment. Just email TLT to reserve the equipment and schedule training, if necessary.
Next, you will need to film your subject. The day before the shoot, contact your subject and instruct him/her NOT to wear green or yellow (which can green around the edges). Set up the light kit using the three-point lighting method (see diagram above). Place a piece of painter’s tape, on the ground, about two feet in front of the green screen. This will mark the exact spot where your subject should stand–keeping shots consistent with regard to lighting, focus, and sound.
Import your footage, and any background images (preferably .PNG or .JPG files), into a New Event. ***Remember to use high-resolution (i.e., 1280 x 720+) images to prevent pixelation.
Add the background image to the Timeline, first, then drag the video clip on top. The video clip will most likely be longer than the image file. Simply drag the image to match the video’s duration.
Select the video and click on the Video Overlay Settings icon. Change the option from Cutaway to Green/Blue Screen. This will change the green screen to your background image.
If your lighting is good, you shouldn’t have to remove any excess green. But, if you do, select the eraser (next to Clean-up) and click on any trouble spots.
Finally, you may notice your video moving in or out, during playback, due to the Ken Burns effect. To keep your video stationary, select the Cropping icon and select Fit or Crop to Fill (to eliminate black bars).
Chris: If I have a shot that includes a normal background–maybe outside in the yard or in a bedroom–is it possible in iMovie to replace the background with a solid black background–as if the shot were done against a black backdrop? Thanks
Thanks for the question, Murray! Unfortunately, iMovie will only replace blue and green backgrounds–solid backgrounds work best. If the background is not solid, for example, a yard with green grass, oaks trees, and a white picket fence, iMovie will replace the grass with a black backdrop, but not the trees (i.e., trunks and branches) or fence. I hope this helps!
Hey Chris! What if my video has a solid WHITE background? Will it still change effectively?
Sorry, Fate, iMovie is limited to blue and green backgrounds with respect to chroma keying.
What if I have a regular background but the sunlight changed from bright to dark. How do I change it if I can?
Kekoa, as long as the dark background is green or blue, you should still be able to key it. However, you will probably need to use the Clean-up eraser (described above) for trouble spots. Thanks!