I love using my green screen for visual effects. If used properly, it allows for a vast number of cool effects to be created with relative ease :) However, if you are not careful during filming you could end up with a number of problems in post production that will hinder if not completely block the visual effect you had in mind.
To not let all my failed attempts go to waste, I decided to create a video tutorial on the most common green mistakes and how you can avoid them!
How to Avoid 5 Common Green Screen Mistakes – Visual Effects 101
Here is a quick summary of the 5 most common green screen mistakes and some tips on how to avoid or fix them :)
1. Shadows on the Green Screen
If your subject is too close to the green screen or the light from the front is too strong, a dark shadow might be cast onto your green screen.
This can cause unpleasant artefacts when you finally try to apply the chroma key. Because the dark areas on the green screen are too close in colour to the dark areas of your subject it may be hard to key them out cleanly.
On the right side it’s hard to tell where the arm ends and the shadow on the green scren begins.
Position your subject a little bit at a distance to the green screen to reduce the shadows.
Try to avoid a single hard light on your subject which will cause strong shadows.
Add lights behind your subject that are aimed at the green screen to brighten up the dark areas.
2. Unevenly lit Green Screen
This problem is very similar to the previous one. While the green screen is now better lit, the lighting is very uneven, creating dark and bright areas in the background.
Again, this can make the application of the chroma key difficult without clipping away parts of your subject. Here is an image of what the unmodified screen matte looks like.
Sometimes you can rectify the solution in post by carefully controlling the ‘deposit black’ and ‘deposit white’ parameters in your Keylight Effect (if in After Effects). Other compositing software chroma key effects will have similar options, so try this first :)
To prevent getting into this situation to begin wtih, try to add lights aimed at your green screen to even out the lighting before you shoot.
Keep reading to discover how to avoid other common green screen mistakes!