Green screening in iMovie
‘Green screening’ is the process of filming a foreground against a green screen (it can also be blue I think!) then choosing a background – either video or image – and overlaying the foreground with anything appearing green being set to ‘allow’ through the background. The effect enables pupils to appear in videos to be transported to any imaginable location, including their own creations if they were to import photos of their own drawings!
Since the scope for using green screening as a tool to enhance engagement and learning across the curriculum is significant and it is pretty straightforward to do in iMovie, I thought I’d write a quick blog post to describe how:
The first thing to do is open iMovie and start a new project. We then need to turn on green screening capabilities which is achieved by selecting preferences from the iMovie menu and ticking the box ‘Show Advanced Tools’. See below.
We now need to import into our project the two components that’ll make up our finished background: a background image or video and a foreground video.
Considering first the case where the background is an image, this can easily be saved from an internet search, or, as mentioned above could be a picture captured of pupils’ own drawing. This should be imported into the iMovie project – one way to do this is to save it to the background and then drag it into the project window. Once into the project, by clicking on the image you can adjust the time that it appears for. Set this figure to a period of time long enough to remain in the background throughout the duration of the foreground video.
The second element of your green screening video, the foreground, is now required. When filming this, set up a ‘green screen’. These can be purchased from Amazon for £25 or can be constructed from green backing paper on a board etc. You should film against this with the knowledge that wherever green is recorded the background will appear through.
Like the picture, the film should then be imported into iMovie. Once in iMove it can now be dragged into the project window and placed over the image. As ‘Advanced tools’ are set to on, when you release the video you’ll get an options box as shown in the screen shot below.
From these options, select ‘Green screen’ and the video will be placed ‘over’ the image with the areas of green replaced with the background and that’s it! Green screening video completed which can now be exported as any other project can from iMovie.
Using video for a background: the process for green screening with a video background is identical with the only difference being that the first step involves you importing a video for the background. Such videos could be filmed yourself or you can use a website, such as www.keepvid.com, to download videos from Youtube or Vimeo.