Green Screens and Cbeebies (Digital Compositing Project)

This semester at Salford University I’ve been taking a course in Digital Compositing – using programmes like After Effects to create visual effects for film and video. For my I was given the brief to create a short promotional film for Cbeebies. I did some research on the Cbeebies brand, and picked up on the little yellow blobs, (which I believe are called bugs, at least this is how they are referred to in the picture files on their website.)

(Picture from

Since the short would need to finish with the Cbeebies logo against a white background, I came up with the idea of the bugs taking the words of the logo to the studio. This would involve live action shots in a montage with 2-D characters superimposed on the top. (I’ll make a post going into more detail about this soon)

Yesterday I got some time in the a Greenscreen TV studio at MediaCityUK to shoot a few elements of the film.

(Picture from

One is from the first scene is the film, when the bugs are gathered on a grassy lawn, and a football bounces through. This could have been achieved in the real life shoot if I had had extra people helping me when I filmed the lawn, but this wasn’t possible, and it also gave me the opportunity to show certain compositing effects.

The ball used was slightly shiny and reflected some of the green on the floor, but this isn’t a problem as it will be bouncing off grass in the actual film and instead actually made the shot look more realistic.

The other prop I needed to be greenscreened was a ladder, which the animated bugs need to climb to put up the letters of the logo. Unlike the ball, which was easily picked up in Tescos, this needed to be custom built.

The next few paragraphs are basically about woodworking – I wanted to talk about how I built the props. While prop sourcing and building is a very important part of film making it’s not terribly relevant to the rest of my blog, so feel free to skip ahead three paragraphs to where I talk about filming again.

I decided the the ladder didn’t need to be very big – only big enough that the camera could pick out the detail on it, so I built a prop ladder about eight inches tall, using some pieces of silk stretching frame (made of pine wood) for the vertical pieces, craft sticks (pieces of wood like small lollipop sticks) for the rungs and sides, and a square of balsa wood for the seat at the top

The vertical pieces were cut down to size using a small hacksaw and shaped diagonally at the top and bottom using a craft knife, then the laid down whilst the rungs were glued in place using strong wood adhesive.

(Gluing together the ladder)

(Warning: Sharp objects and fingers should not mix.)

When the rungs were dry, the top diagonal pieces were glued together with both sides clamped in place, then the side pieces were added separately. Finally, I cut a piece of balsa wood down to size and glued it to the top two rungs to create a top step.

(The Robert Jordan novels make good makeshift clamps!)

This Monday, I finally got into the green screen studio to shoot. The film was shot on a 1080 HD camera, against a green screen approximately 15 foot across, with a green floor extending out about 12 foot. The ball required a few attempts to film and as needed to bounce in a straight line – two of us spent about ten minutes bouncing it in and out of shot!

The model ladder was much easier as it essentially involved stills in three different position. There was some concern among the group of people in the studio that because the camera was zoomed in quite far, it was showing up problems with the Green screen floor such as tape, although I am confident that these can be resolved in post by masking in After Effects.

So at this point my next step is to drop the green screened items into the live footage. The ladder will be quite easy, as it will be placed against a white ‘virtual studio’ background – it will only need a shadow to make it convincing. The ball will be harder, not just because it’s shadow will need to move with it and change in size/opacity, but because it needs to look as it is disturbing the grass in the scene slightly. There are several small effects that could possibly be added to achieve this. One is deforming the ball as it hits the ground, a other is to use careful masking to make the ball appear to sink into the grass slightly. I’m mostly going to be experimenting from here on out, and I’ll try to remember to do updates on this project.


3 thoughts on “Green Screens and Cbeebies (Digital Compositing Project)

  1. Pingback: Sound Design and Music (Starting Out) | Internet Culture and Audio Attempts
  2. Pingback: Sound Design Updates – Going for ‘Simple’ | Internet Culture and Audio Attempts
  3. Pingback: First Foray into Animation – Cbeebies Short Project | Internet Culture and Audio Attempts

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