Green screening

Posted on November 21, 2012 by Claire.
Categories: mobile technologies.

Surprisingly you might think, I had come across the concept of Green-screens prior to this session.  However I had only ever seen them used by professional companies, usually in the run up to Christmas when they set up in a shopping centre and try to convince you to part with your hard earned cash in exchange for a 90 second video/dvd of your child sitting in a sleigh against a green back drop which creates the effect of the sleigh going on a trip through snowfields and dense fir forests in search of Father Christmas etc.  My Dad has always said he would love to have a go on one of those but being the ‘goat’ that he is would love to pretend to fall off the back of the sleigh and then slowly but surely, one hand at a time and lots of effort later clamber back onto the sleigh looking somewhat worse for wear – sorry just thought I would throw that in as the idea of my dad doing that really makes me chuckle and I know he would do such a good job of it.

So we got to play with green-screen technology then.  This involved someone sitting/standing/dancing whatever in front of a green screen whilst the person with the recording equipment – in this case  an ipad – photographs them against a chosen background which can only be seen on the screen; it is important to make the floor green if you want to get their feet in the shot.

Once you have your photo you can up load it onto from a saved file.  It is important – as we found out through LOTS of trial and error – to rotate your photo so that it is the correct way up before uploading to the site as it cannot be done on there.  First you open the background and re-size it to what you are happy with.  Then click on the ‘layers’ button and choose to ‘import from file’.  You now select the photo of your actor/victim.  Your person against the green backdrop now appears on the screen.  Click on ‘effects’, ‘photo’ and ‘Chroma key’.  You can then adjust the background so that it disappears and you are left with your person against the intended backdrop.  You can also re-size the person making them larger/smaller as necessary.  The photo (right) is the outcome of our session.  If you look carefully at the pictures along the top you can sort of see the (disjointed) process we went through to get the overall effect.

Movie FX is a film making app available on ipads that uses background images or videos to place your person (who is standing against a green backdrop) in the scene.  You simply point the camera at the green-screen and select the colour background on the screen that you are using.  You then point the camera at your actor standing in front of the green screen, use the slider to adjust the contrast and press the red button to begin recording.  This app was very straightforward to use although we did have problems with the contrast cutting out too much of the person or not enough of the background.  Once you have a contrast you are happy with though all that is involved is directing and filming.  Here is a link to Jenny’s post which contains the video we made together.

In school green screens could be used for a number of purposes.  At the most basic level they could be used as a backdrop for making personalised Christmas, Easter, Valentines, Diwali, Halloween (the list is endless) cards for children to take home for family or as keepsakes.  It could be better used for presentational purposes.  Children could make documentaries about a trip to somewhere they have been learning about e.g Egypt, Ancient Rome, The Grand Canyon etc.  Pupils could even get creative by presenting on the Great Barrier Reef or from a river bed by finding a suitable background and then ‘donning’ the right grear e.g. a snorkel, mask and flippers.  The child could then make incomprehendible sounds through the snorkel whilst holding up scripted placards to deliver the information.  It would certainly create a few laughs.   This could even be given a whole school approach with each year group creating a short newsreel about the topic they have been studying and then putting this all together to create a whole school news report to be shown in an assembly, at parents evening, open days etc.  I saw something similar to this – but without the green-screen – in my daughter’s class assembly last year.  They had been learning about mega-structures and their class assembly was a newsreel shot in various locations around the school grounds using replicas of famous mega-structures that they had built.  This was very enjoyable but could have been enhanced greatly by using green-screens.  They could even have put their reporter and mega-structure against a completely incorrect backdrop e.g. the Eiffel tower in the Sahara Desert and then reported on how many mega-structures had been mysterious relocated overnight and then give the history of the mega-structures etc.  At the end they could have shown the reporters at the real sites declaring that all was well now as the mega-structures had been returned safely to their correct locations.  I am in no way insulting or belittling what was done by the school as it was very creative on the children’s parts, required a certain amount of artistic licence and imagination on the parents parts and was certainly highly amusing.  Its just a shame I didn’t record it.

Here then is a funny little clip I found of how green-screening can be used with amateurs to demonstrate the effect it can create.


This link takes you to a series of short films all about using green-screening with pupils and covers everything to do with film making really.  It is from a website containing a wealth of information for teachers on many aspects of using creative arts in school.


This final video is a fantastic example of how green-screening can be used with children.  Wouldn’t it be fantastic to be able to do something like this with pupils, perhaps for the Christmas production which parents could then come to and watch just like at the cinema.  The school could even raise money by selling hotdogs, popcorn and ice cream! (Okay so it would take an awful amount of time, planning, organisation, imagination/creativity, resources and staff and pupil collaboration but the final result would be amazing and surely something that would stick in pupils’, teachers’ and parents’ minds probably for the rest of their lives).


Happy green-screening!



Comment on November 22nd, 2012.

Hi! I really enjoyed reading this post! I saw people using the green screening but did not get to use it myself! i love that it can now be used in schools with children as they can enter and exit any world that they chose and really use I.c.t to make their imaginations become reality!


    Comment on November 23rd, 2012.

    It was a lot of fun. It does take a bit of getting your head around so I would suggest getting familiar with it at home before attempting it with pupils but it has so much potential to enhance learning across the curriculum


Comment on November 22nd, 2012.

p.s hope the dinosaur spat you back you!


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