Using Green Screens In The Classroom


By Grant Jones

In an increasingly fast paced education system, we can’t simply have new technologies as add-ons, we must think of innovative and creative ways to integrate technology into our future focused curriculum. There few things more annoying to a teacher than having yet another program thrown across the table and being told ‘this needs to be implemented into your program.’ We as teachers need to work smarter, not harder, when integrating technology into our learning and teaching programs. One of the most ingenious ways to achieve this is film making using green screen technology. Green screening technology used to be unattainable to the masses but now, with up to date technologies, you can create magic with the click of a button!

Green screen technology align with the ICT Capabilities in the strands of ‘Creating with ICT element of the Australian curriculmn and Communicating with ICT element. It also aligns with Digital Technologies Processes and Production Skills elements outlined in the Australian Curriculum. We, as teachers, have a unique opportunity in the wake of new syllabus documents whichhave come out in the past few years. Technology plays a big part in these new documents. Therefore, teachers should be using this opportunity to create new dynamic units of work with the integration of creative and innovative technologies such as green screening.

Through the magic of this technology, you can superimpose your students onto virtual backgrounds, place them over animated digital backdrops or transport them to a desert oasis. The secret to pulling your student out of the real world and placing him or her into a digital domain is Chroma key, and that means going green.  The reason for using green as a background colour (hence the term green screen) is because this colour does not appear naturally in the pigment of the human skin. Some people choose to use blue as a background colour (blue screen) however, green is used more often today because of the sensitivity and processing of the color channels in the digital cameras most people shoot with. I say sensitivity and processing (sampling), because these are two distinctly different factors. One affects the noise level, the other affects the actual resolution of that channel. And both are important to good keying results.

The green channel is the cleanest channel in most digital cameras today. The green channel has the highest luminance of all three (red, green and blue) digital channels, and thus the sensors deliver the least noise in that channel. The processing is three-fold: There is Bayer Pattern filtering (which occurs in single CMOS/CCD sensors, but not 3-CCD cameras), DSP (digital signal processing) and the processing in the actual recording format.

Bayer Pattern means that the sensor has a filter arrangement on its pixel array that actually records twice as many green pixels as red or blue. So the actual recording resolution of the green channel is double that of the other channels.

Digital Signal Processing, or usually referred to as the “matrix”, can (and should) in some cameras be turned off. In some cameras, it cannot be completely turned off, but at least the most detrimental feature for keying, image sharpening, can be turned off.

The recording format is another factor. However, this begins to get extremely technical and is probably well beyond the scope of this article.

A simple classroom set up would consist of a green screen for students to stand in front of, lighting to light the green screen as well as the subject, a tripod with an iPad mount, boom mic, an iPad with a green screening app and iMovie and most importantly, a creative mind!

Many green screening apps and websites talk about Chroma key. But what is it?

In simplest terms “Chroma” refers to colour and ‘key’ or ‘keying’ is a term used in the video editing world which means, “to remove.” Therefore, ‘keying out’ the green will leave you with a transparent background allowing you to place any background you want behind your student.
Green Screen technology is all about turning students into innovative and creative film makers. Any student can achieve success using green screen technology. Whether it be creating a digital recount of an excursion or a travel information documentary about a country being studied. Gone are the days of simply using a PowerPoint presentation to talk about landmarks around the world. Instead of a slideshow with sound and/or video, your student can produce a film where he or she is standing on the Great Wall of China. They could start their project on a plane for example, acting the role of a flight attendant talking about a place they want to take the viewer. Then, with green screen technology and the click of a button, the presenter is at the LANDMARK!

With ever changing technological advances, there is no need to film and download your footage onto a computer and use programs to take out the green and then superimpose the background. Everything can now be done on an iPad. Using apps such as Veescope and Green Screen Pro, you can now import desired backgrounds and videos you want in the background and, with use of the green screen, you can film your scene. Once your students have finished filming, they simply upload to iMovie and edit straight on the iPad that you used to film. The iPad is your one stop movie making device.
Not only does green screen film making promote technology, it also allows students to use their modern learning skills. Once this technology is incorporated into units of work, students can work in groups to collaborate and create short films on desired themes. According to Ian Jukes and Ted McCain, the 9 I’s of modern learning include intrapersonal skills, interpersonal skills, independent problem solving skills, interdependent collaboration skills, information investigation, information presentation, imagination creativity skills, innovation creativity skills and internet citizenship skills. Students would cover a majority of these skills when using this type of film making. From collaborating with each other, to creating the script, to using the internet to investigate and download backgrounds to go with their creative and imaginative film.

In conclusion, this technology which was once an awe-inspiring feat only attainable if you were working in the film industry on the backlots of Universal Studios is now readily available and easy and engaging for your classroom. Whether you teach preschool ages students or Year 12 students, green screen technology definitely has a place embedded into your learning and teaching program. If you already have iPads in your school, then you are well on your way to integrating green screen technology.

A wise man once said to me, “I can’t wait for the day when we say to our students that we are going to the tech hub to do an English lesson with the help of green screen technology rather than saying we are going to the tech hub to learn technology. Integration and embedding technology is the key.”

Grant Jones is a Technology Teacher and PBL Leader St Marys Public School in St Marys.

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Education Technology Solutions has been created to inspire and encourage the use of technology in education. Through its content, Education Technology Solutions seeks to showcase cutting edge products and practices with a view to expanding the boundaries and raising the standards of education curricula. It introduces teachers and IT staff to the latest products, services and developments in education technology with a view to providing practical how-to guidance designed to facilitate the integration of those products and services into the school environment in the most productive and beneficial manner possible.

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